Dry etching method, cleaning method, semiconductor device production method, and etching device

Abstract

Provided are a dry etching method in which a film containing a metal element can be etched, a cleaning method, a semiconductor device production method, and an etching device. The present invention relates to a dry etching method in which an etching target film containing a metal element is etched with hydrocarbon group-containing phosphine and a Bronsted acid.

Description

Dry etching method, cleaning method, semiconductor device manufacturing method and etching apparatus

[0001] The present disclosure relates to a dry etching method, a cleaning method, a method for manufacturing a semiconductor device, and an etching apparatus.

[0002] In the manufacturing process of semiconductor devices, metal films formed on substrates as wiring materials, metal gate materials, electrode materials, or magnetic materials are often etched. For example, organic molecular materials that form complexes with metals and can be etched in the etching of such metal films have been developed.

[0003] As a method for etching such a metal film, for example, a method using trimethylphosphine and SO ２ Cl ２ There is known a method for etching Ni and Co by using a method such as the following (Non-Patent Documents 1 and 2).

[0004] Chem. Mater. 2021, 33, 9174-9183J. Vac. Sci. Technol. A 2023, 41 (3), 032603

[0005] There is a potential need for techniques other than those described in Non-Patent Documents 1 and 2 that are capable of etching films containing metal elements.

[0006] The present disclosure aims to solve the above-mentioned problems and to provide a dry etching method, a cleaning method, a semiconductor device manufacturing method, and an etching apparatus that are capable of etching a film containing a metal element.

[0007] As a result of extensive research, the present inventors have found that a film containing a metal element can be etched by using a Brønsted acid together with a hydrocarbon group-containing phosphine, and have thus completed the present disclosure.

[0008] That is, the present disclosure (1) relates to a dry etching method for etching a film containing a metal element using a hydrocarbon group-containing phosphine and a Bronsted acid.

[0009] The present disclosure (2) relates to the dry etching method according to the present disclosure (1), wherein the Bronsted acid is a compound that becomes at least one anion selected from the group consisting of an anion represented by the following formula (1), an anion represented by the following formula (2), and an anion represented by the following formula (3) after releasing a proton: X － (1) (In formula (1), X is a halogen atom or a hydroxy group.) RO － (2) (In formula (2), R is a monovalent hydrocarbon group or a monovalent halogenated hydrocarbon group.) RCOO － (3) (In formula (3), R is a hydrogen atom, a monovalent hydrocarbon group, or a monovalent halogenated hydrocarbon group.)

[0010] The present disclosure (3) relates to the formula (2) and the dry etching method according to the present disclosure (2), wherein R in the formula (3) is a monovalent hydrocarbon group having 5 or less carbon atoms or a monovalent halogenated hydrocarbon group having 5 or less carbon atoms.

[0011] The present disclosure (4) relates to the dry etching method according to the present disclosure (1), wherein the Bronsted acid is at least one selected from the group consisting of hydrogen halide, carboxylic acid, alcohol, and water.

[0012] The present disclosure (5) relates to the dry etching method according to the present disclosure (1), wherein the Bronsted acid is at least one selected from the group consisting of hydrogen chloride, hydrogen bromide, hydrogen iodide, hydrogen fluoride, water, acetic acid, methanol, ethanol, and isopropyl alcohol.

[0013] The present disclosure (6) relates to the dry etching method according to any one of the present disclosures (1) to (5), wherein the hydrocarbon group of the hydrocarbon-group-containing phosphine is at least one selected from the group consisting of a methyl group, an ethyl group, a cyclohexyl group, and a phenyl group.

[0014] The present disclosure (7) relates to the dry etching method according to any one of the present disclosures (1) to (5), wherein the hydrocarbon group-containing phosphine is at least one selected from the group consisting of trimethylphosphine, triethylphosphine, tricyclohexylphosphine, and triphenylphosphine.

[0015] The present disclosure (8) relates to the dry etching method according to any one of the present disclosures (1) to (7), wherein the film to be etched is a film to be etched that contains a metal including at least one selected from the group consisting of In, Sn, Zn, Ga, Hf, Zr, Al, Ta, Ti, Fe, Co, and Ni, an oxide of the metal, or a nitride of the metal.

[0016] The present disclosure (9) relates to the dry etching method according to any one of the present disclosures (1) to (7), wherein the film to be etched is a film to be etched that contains a metal containing at least one selected from the group consisting of In, Sn, Zn, Hf, Al, and Zr, an oxide of the metal, or a nitride of the metal.

[0017] The present disclosure (10) relates to the dry etching method according to any one of the present disclosures (1) to (9), in which the etching temperature is 100° C. or higher.

[0018] The present disclosure (11) relates to the dry etching method according to any one of the present disclosures (1) to (10), in which a gas A containing the hydrocarbon group-containing phosphine and the Bronsted acid is brought into contact with the film to be etched.

[0019] The present disclosure (12) relates to the dry etching method according to the present disclosure (11), wherein the amount of the hydrocarbon group-containing phosphine contained in the gas A is 5 to 99% by volume.

[0020] The present disclosure (13) relates to the dry etching method according to the present disclosure (11) or (12), wherein the amount of the Bronsted acid contained in the gas A is 0.1 to 65% by volume.

[0021] The present disclosure (14) relates to the dry etching method according to any one of the present disclosures (1) to (10), which includes a first step of contacting the film to be etched with a gas B containing the Bronsted acid, and a second step of contacting the film to be etched with a gas C containing the hydrocarbon group-containing phosphine.

[0022] The present disclosure (15) relates to the dry etching method according to any one of the present disclosures (1) to (14), which selectively etches a film to be etched that contains a metal element relative to a silicon-containing film.

[0023] The present disclosure (16) relates to a cleaning method for removing deposits containing metal elements deposited on the surface of a processing vessel of a substrate processing apparatus using a hydrocarbon group-containing phosphine and a Bronsted acid.

[0024] The present disclosure (17) relates to a method for manufacturing a semiconductor device, including a step of applying the dry etching method according to any one of the present disclosures (1) to (15) to a film containing a metal element on a substrate, thereby etching the film.

[0025] The present disclosure (18) relates to an etching apparatus including: a mounting table for mounting an object to be processed; a hydrocarbon group-containing phosphine gas supply unit for supplying a gas containing a hydrocarbon group-containing phosphine to the object to be processed; and a Brønsted acid gas supply unit for supplying a gas containing a Brønsted acid to the object to be processed.

[0026] The dry etching method of the present disclosure is a dry etching method in which a film to be etched containing a metal element is etched using a hydrocarbon group-containing phosphine and a Bronsted acid, and therefore can etch a film containing a metal element.

[0027] The cleaning method disclosed herein is characterized by removing deposits containing metal elements deposited on the surface of a processing vessel of a substrate processing apparatus using a hydrocarbon group-containing phosphine and a Brønsted acid, and therefore can remove deposits containing metal elements deposited on the surface of a processing vessel of a substrate processing apparatus.

[0028] The method for manufacturing a semiconductor device according to the present disclosure includes a step of applying the dry etching method according to the present disclosure to a film containing a metal element on a substrate to etch the film. Because the method for manufacturing a semiconductor device according to the present disclosure includes a step of etching using the dry etching method according to the present disclosure, it is possible to etch the film containing a metal element and produce a high-quality semiconductor device.

[0029] The etching apparatus of the present disclosure comprises a mounting table for mounting an object to be processed, a hydrocarbon group-containing phosphine gas supply unit for supplying a gas containing a hydrocarbon group-containing phosphine to the object to be processed, and a Brønsted acid gas supply unit for supplying a gas containing a Brønsted acid to the object to be processed, and therefore can etch a film containing a metal element.

[0030] FIG. 1 is a schematic diagram of an etching apparatus of the present disclosure.

[0031] The present disclosure will be described in detail below, but the following description of the constituent elements is an example of an embodiment of the present disclosure, and the present disclosure is not limited to these specific details. Various modifications can be made within the scope of the gist of the present disclosure.

[0032] In this specification, unless otherwise specified, the expression "X to Y" in the description of a numerical range means at least X and at most Y. For example, "1 to 5% by mass" means "at least 1% by mass and at most 5% by mass."

[0033] <Dry Etching Method> The dry etching method of the present disclosure is a dry etching method for etching a film to be etched that contains a metal element using a hydrocarbon group-containing phosphine and a Bronsted acid. This allows etching of a film that contains a metal element. The dry etching method of the present disclosure also allows etching of a film that contains silicon oxide (SiO ２ ), and can suppress damage to silicon-containing films such as silicon nitride (SiN), so that it is possible to etch a film containing a metal element while suppressing damage to the silicon-containing film.

[0034] Although the reason for the above-mentioned effect is not entirely clear, it is presumed to be due to the following mechanism. After releasing a proton, the Brønsted acid becomes an anion and coordinates with the metal element contained in the film to be etched. Subsequently, a hydrocarbon group-containing phosphine coordinates with the complex of the metal element and the Brønsted acid-derived anion, forming a complex of the metal element, the Brønsted acid-derived anion, and the hydrocarbon group-containing phosphine. Because this complex has a high vapor pressure, the film to be etched can be removed by vaporizing the complex. Furthermore, since the complex can be formed, etching can be performed without generating plasma. This eliminates the risk of electrical damage to the substrate caused by plasma gas. Furthermore, because the Brønsted acid has relatively weak oxidizing power, it cannot etch the silicon-containing film, thereby suppressing damage to the silicon-containing film.

[0035] On the other hand, SO is not a Brønsted acid. ２ Cl ２ and Cl ２ has a very strong oxidizing power and therefore etches the silicon-containing film, causing damage to the silicon-containing film. ２ Cl ２ and Cl ２ has a very strong oxidizing power, and even hydrocarbon group-containing phosphines are oxidized (chlorinated), causing the valence of the phosphine to change irreversibly from trivalent to pentavalent. When the valence of the phosphine is trivalent, it can be coordinated to a metal element, but when the valence of the phosphine is pentavalent, it cannot be coordinated to a metal element, and as a result, etching does not proceed. Therefore, SO ２ Cl ２ and Cl ２ When using SO ２ Cl ２ and Cl ２ It is not possible to simultaneously bring the etchant into contact with the film to be etched and the hydrocarbon group-containing phosphine, that is, to supply them simultaneously.

[0036] On the other hand, in the case of a Brønsted acid as disclosed herein, the Brønsted acid does not react with the hydrocarbon group-containing phosphine or merely forms a salt with the hydrocarbon group-containing phosphine, and the valence of the phosphine remains trivalent, so that the valence is easily dissociated by heating. As a result, the hydrocarbon group-containing phosphine can be coordinated to a metal element, and the hydrocarbon group-containing phosphine and the Brønsted acid can be simultaneously brought into contact with the film to be etched, i.e., simultaneously supplied.

[0037] Furthermore, in the technology using HFAc (hexafluoroacetylacetone), which is a β-diketone, a fluorine-containing compound is used, and therefore there is a concern that the film to be etched may be contaminated with fluorine atoms. On the other hand, since hydrocarbon group-containing phosphines do not contain fluorine atoms, concerns about fluorine atom contamination of the film to be etched can be eliminated as long as the Bronsted acid also does not contain fluorine atoms. Furthermore, since hydrocarbon group-containing phosphines do not contain fluorine atoms, concerns about fluorine atom contamination of the film to be etched can be reduced even if the Bronsted acid contains fluorine atoms.

[0038] The silicon-containing film is not particularly limited as long as it contains silicon, and examples thereof include a film containing at least Si and O (preferably a film containing at least Si and O but not N), a film containing at least Si and N, etc. These may be used alone or in combination of two or more.

[0039] As a film containing at least Si and O (preferably a film containing at least Si and O and not containing N), silicon oxide (SiO, where SiO does not indicate the stoichiometric ratio of each element, but refers to a film containing silicon atoms and oxygen atoms. For example, SiO ｘ (x is 1 or more and 2 or less) and SiO ２ In this specification, a film containing at least Si and O but not N means that the N content in 100% by mass of the film is 1% by mass or less, preferably 0.1% by mass or less, more preferably 0.01% by mass or less, and even more preferably 0.00% by mass.

[0040] As a film containing at least Si and N, silicon nitride (SiN, where SiN does not indicate the stoichiometric ratio of each element, but refers to a film containing silicon atoms and nitrogen atoms. For example, SiN ｘ (x is 0.3 or more and 9 or less) and Si ３ N ４ ) film, silicon oxide carbonitride (SiOCN, where SiOCN does not indicate the stoichiometric ratio of each element, but refers to a film containing silicon atoms, oxygen atoms, carbon atoms, and nitrogen atoms.) film, silicon oxynitride (SiON, where SiON does not indicate the stoichiometric ratio of each element, but refers to a film containing silicon atoms, oxygen atoms, and nitrogen atoms. For example, Si ４ O ｘ N ｙ (x is 3 or more and 6 or less, y is 2 or more and 4 or less) or Si ４ O ５ N ３ ) film, and silicon carbide nitride (SiCN; here, SiCN does not indicate the stoichiometric ratio of each element, but refers to a film containing silicon atoms, carbon atoms, and nitrogen atoms. For example, a material containing 20 to 50 atomic % of silicon, 5 to 30 atomic % of carbon, and 10 to 30 atomic % of nitrogen) film.

[0041] The silicon-containing film is preferably a film containing at least Si and O (preferably a film containing at least Si and O and not containing N), more preferably a silicon oxide film, and more preferably SiO ２ A membrane is more preferred.

[0042] In the dry etching method of the present disclosure, a silicon-containing film (preferably SiO ２ The etching rate for the film is preferably 0.5% by mass / min or less, and more preferably 0.1% by mass / min or less. The lower limit is not particularly limited, but is, for example, 0.001% by mass / min or more. In this specification, the etching rate is calculated by the method described in the Examples.

[0043] The dry etching method of the present disclosure is a method for converting a film to be etched that contains a metal element into a silicon-containing film (preferably SiO ２ In this specification, the term "etching a film containing a metal element to be etched with a silicon-containing film (preferably SiO２ The phrase "selectively etch a film containing a metal element and a silicon-containing film (preferably SiO ２ The ratio of the etching rate of the film to be etched containing a metal element / the silicon-containing film (preferably SiO ２ The etching rate ratio is preferably 5 or more, more preferably 10 or more, and even more preferably 50 or more. The upper limit is not particularly limited, but is, for example, 1000 or less.

[0044] <<Film to be etched>> The metal element contained in the film to be etched by the dry etching method of the present disclosure is not particularly limited, and examples include In (indium), Sn (tin), Zn (zinc), Ga (gallium), Hf (hafnium), Zr (zirconium), Al (aluminum), Ta (tantalum), Ti (titanium), Fe (iron), Co (cobalt), Ni (nickel), etc. These may be used alone or in combination of two or more.

[0045] The metal element contained in the film to be etched may be a metal, a metal oxide, or a metal nitride. Of course, it may also be an alloy containing two or more of the above-mentioned metals, an alloy oxide, or an alloy nitride. These may be used alone or in combination of two or more. Among these, metal oxides and alloy oxides are preferred, and metal oxides are more preferred.

[0046] The film to be etched preferably contains a metal containing at least one selected from the group consisting of In, Sn, Zn, Ga, Hf, Zr, Al, Ta, Ti, Fe, Co, and Ni, an oxide of the metal, or a nitride of the metal, more preferably a metal containing at least one selected from the group consisting of In, Sn, Zn, Ga, Hf, Zr, Al, and Ti, an oxide of the metal, or a nitride of the metal, still more preferably a metal containing at least one selected from the group consisting of In, Sn, Zn, Hf, Al, and Zr, an oxide of the metal, or a nitride of the metal, and particularly preferably a metal containing at least one selected from the group consisting of In, Sn, Zn, and Zr, an oxide of the metal, or a nitride of the metal.

[0047] The above metals are preferably In, Sn, Zn, Ga, Hf, Zr, Al, and Ti, more preferably In, Sn, Zn, Hf, Al, and Zr, and even more preferably In, Sn, Zn, and Zr.

[0048] Examples of the oxides of the above metals include indium oxide (InO ｑ (q is 1 or more and 2 or less), especially In ２ O ３ ), tin oxide, zinc oxide, gallium oxide (GaO ｐ (p is 1 or more and 2 or less), especially Ga ２ O ３ ), hafnium oxide (HfO ｘ (x is 1 or more and 3 or less), especially HfO ２ ), zirconium oxide (ZrO ｕ (u is 1 or more and 3 or less), especially ZrO ２ ), aluminum oxide (AlO ｖ (v is 1 or more and 2 or less), especially Al ２ O ３ ), tantalum oxide, titanium oxide (TiO ｗ (w is 1 or more and 3 or less), especially TiO ２ ), iron oxide, cobalt oxide, nickel oxide, indium gallium zinc oxide [In ａ Ga ｂ Zn ｃ O ｄ (a and b are 1 or more and 3 or less, c is 0.5 or more and 4 or less, and d is 4 or more and 10 or less, abbreviated as "IGZO"). InGaZnO ４ , In ２ Ga ２ ZnO ７ etc. (InGaO ３ ) ａ (ZnO) ｃ It is preferable that the compound is represented by the formula: ], indium tin oxide (indium oxide (In ２ O ３ ) and tin oxide (SnO ２ ), a mixture of silicon hafnium oxide, aluminum hafnium oxide, and zirconium hafnium oxide (HfZrO ｘ (x is 1 or more and 3 or less), especially HfZrO ４) and the like. These may be used alone or in combination of two or more. Among them, indium oxide, tin oxide, zinc oxide, gallium oxide, hafnium oxide, zirconium oxide, aluminum oxide, titanium oxide, indium gallium zinc oxide, indium tin oxide, silicon hafnium oxide, aluminum hafnium oxide, and zirconium hafnium oxide are preferred, indium oxide, tin oxide, zinc oxide, hafnium oxide, zirconium oxide, aluminum oxide, indium gallium zinc oxide, indium tin oxide, aluminum hafnium oxide, and zirconium hafnium oxide are more preferred, indium oxide, tin oxide, zinc oxide, zirconium oxide, indium gallium zinc oxide, indium tin oxide, and zirconium hafnium oxide are even more preferred, and indium oxide, tin oxide, zinc oxide, and zirconium oxide are particularly preferred. Note that other elements may be added to the metal oxide, and for example, rare earth elements such as lanthanum and yttrium may be added.

[0049] Examples of the nitrides of the above metals include indium nitride, tin (IV) nitride, zinc nitride, gallium nitride compounds, hafnium nitride, zirconium nitride, aluminum nitride, tantalum nitride, titanium nitride, iron nitride, cobalt nitride, nickel nitride, aluminum gallium nitride, and indium gallium nitride. These may be used alone or in combination of two or more. Among these, indium nitride, tin (IV) nitride, zinc nitride, gallium nitride compounds, hafnium nitride, zirconium nitride, aluminum nitride, titanium nitride, aluminum gallium nitride, and indium gallium nitride are preferred, indium nitride, tin (IV) nitride, zinc nitride, hafnium nitride, zirconium nitride, aluminum nitride, and indium gallium nitride are more preferred, indium nitride, tin (IV) nitride, zinc nitride, zirconium nitride, and indium gallium nitride are even more preferred, and indium nitride, tin (IV) nitride, zinc nitride, zirconium nitride, and indium gallium nitride are particularly preferred.

[0050] In the dry etching method of the present disclosure, examples of the object to be processed include a silicon substrate, a compound semiconductor substrate, a quartz substrate, and a glass substrate. In addition to the above-mentioned film to be etched, a silicon film, a silicon oxide film, a silicon nitride film, a metal wiring film other than the above-mentioned metals, etc. may be formed on the surface of the object to be processed. In particular, a film containing at least Si and O (preferably a film containing at least Si and O and not containing N, more preferably SiO ２ It is preferable that a film (film) is formed.

[0051] The method for forming the etching film on the surface of the workpiece is not particularly limited, but examples thereof include chemical vapor deposition (CVD) and sputtering. The thickness of the etching film is also not particularly limited, but may be, for example, 0.1 nm to 1 μm.

[0052] The dry etching method of the present disclosure uses a hydrocarbon group-containing phosphine and a Bronsted acid.

[0053] <<Hydrocarbon Group-Containing Phosphine>> The hydrocarbon group-containing phosphine is not particularly limited as long as it is a phosphine in which a hydrogen atom is substituted with a hydrocarbon group. The hydrocarbon group-containing phosphines may be used alone or in combination of two or more.

[0054] The number of hydrocarbon groups in the hydrocarbon group-containing phosphine is at least 1, preferably 2, and more preferably 3. When the hydrocarbon group-containing phosphine has two or more hydrocarbon groups, the types of the hydrocarbon groups may be the same or different, but it is preferable that they are the same.

[0055] Examples of the hydrocarbon group contained in the hydrocarbon group-containing phosphine include an alkyl group, an alkenyl group, an alkynyl group, and a phenyl group. These may be used alone or in combination of two or more. Of these, an alkyl group and a phenyl group are preferred. Specific preferred examples of the hydrocarbon group contained in the hydrocarbon group-containing phosphine include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a phenyl group, and a cyclohexyl group. These may be used alone or in combination of two or more. Of these, a methyl group, an ethyl group, a cyclohexyl group, and a phenyl group are preferred, with a methyl group and an ethyl group being more preferred, and a methyl group being particularly preferred. The number of carbon atoms in the hydrocarbon group contained in the hydrocarbon group-containing phosphine is preferably 1 to 6, more preferably 1 to 4, and even more preferably 1.

[0056] Examples of hydrocarbon group-containing phosphines include trimethylphosphine, triethylphosphine, tributylphosphine, triphenylphosphine, dimethylethylphosphine, diethylmethylphosphine, and tricyclohexylphosphine. These may be used alone or in combination of two or more. Among these, trimethylphosphine, triethylphosphine, triphenylphosphine, and tricyclohexylphosphine are preferred, trimethylphosphine and triethylphosphine are more preferred, and trimethylphosphine is even more preferred.

[0057] The gas containing a hydrocarbon group-containing phosphine is not particularly limited as long as it contains a hydrocarbon group-containing phosphine, but may also contain an inert gas in addition to the hydrocarbon group-containing phosphine.

[0058] Examples of inert gases include Ar and N ２ , He, Ne, Kr, etc. These may be used alone or in combination of two or more.

[0059] The content of the hydrocarbon group-containing phosphine in 100% by volume of the gas containing the hydrocarbon group-containing phosphine can be, for example, 10 to 100% by volume. In this case, the content of the inert gas in 100% by volume of the gas containing the hydrocarbon group-containing phosphine can be, for example, 0 to 90% by volume. In this specification, the content of each gas component is measured, for example, by infrared spectroscopy.

[0060] In 100% by volume of the gas containing a hydrocarbon group-containing phosphine, the total content of the hydrocarbon group-containing phosphine 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, particularly preferably 98% by volume or more, and may even be 100% by volume.

[0061] <<Brønsted Acid>> The Bronsted acid is a proton (H ＋ The acid is not particularly limited as long as it releases a proton and functions as a proton donor. A Bronsted acid is an acid having a proton, and is different from an acid without a proton such as a Lewis acid. Bronsted acids may be used alone or in combination of two or more.

[0062] The Bronsted acid may have one hydrogen atom that can be released as a proton.

[0063] The Bronsted acid is preferably a compound that, after releasing a proton, becomes at least one anion selected from the group consisting of an anion represented by the following formula (1), an anion represented by the following formula (2), and an anion represented by the following formula (3): X － (1) (In formula (1), X is a halogen atom or a hydroxy group.) RO － (2) (In formula (2), R is a monovalent hydrocarbon group or a monovalent halogenated hydrocarbon group.) RCOO － (3) (In formula (3), R is a hydrogen atom, a monovalent hydrocarbon group, or a monovalent halogenated hydrocarbon group.)

[0064] Examples of the halogen atom of X include a chlorine atom, a bromine atom, and an iodine atom. These may be used alone or in combination of two or more. Among these, a chlorine atom and a bromine atom are preferred, and a bromine atom is more preferred.

[0065] X is preferably a halogen atom.

[0066] The number of carbon atoms in the monovalent group (monovalent hydrocarbon group, monovalent halogenated hydrocarbon group) for R in formulas (2) and (3) is preferably 5 or less, more preferably 4 or less, and even more preferably 3 or less, for the reason that the Brønsted acid can be more suitably converted into a gas. The lower limit of the carbon atom number is not particularly limited, but is preferably 1 or more.

[0067] Examples of the monovalent hydrocarbon group represented by R in formulas (2) and (3) include alkyl groups, alkenyl groups, and alkynyl groups. Of these, alkyl groups are preferred.

[0068] The alkyl group of R preferably has 1 to 5 carbon atoms, more preferably 1 to 4 carbon atoms, and even more preferably 1 to 3 carbon atoms.

[0069] Examples of the alkyl group represented by R include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, etc. Among these, a methyl group, an ethyl group, an n-propyl group, and an isopropyl group are preferred, and a methyl group, an ethyl group, an n-propyl group, and an isopropyl group are more preferred.

[0070] In this specification, the term "halogenated hydrocarbon group" refers to a hydrocarbon group in which at least a portion of the hydrogen atoms are substituted with halogen atoms, and is the same as a hydrocarbon group, including preferred embodiments, except that at least a portion of the hydrogen atoms are substituted with halogen atoms. Here, the halogen atoms are the same as the halogen atoms of X, including preferred embodiments. Examples of halogenated alkyl groups include trifluoromethyl and difluoromethyl groups.

[0071] In formulas (2) and (3), R is preferably a monovalent hydrocarbon group.

[0072] As the Bronsted acid, hydrogen halide (a compound which becomes the anion represented by the formula (1) after releasing a proton), carboxylic acid (a compound which becomes the anion represented by the formula (3) after releasing a proton), alcohol (a compound which becomes the anion represented by the formula (2) after releasing a proton), and water (a compound which becomes the anion represented by the formula (1) after releasing a proton) are preferred, with hydrogen halide, carboxylic acid, and alcohol being more preferred, and hydrogen halide being even more preferred.

[0073] Examples of hydrogen halides include hydrogen chloride, hydrogen bromide, hydrogen iodide, and hydrogen fluoride. These may be used alone or in combination of two or more. Among these, hydrogen chloride, hydrogen bromide, and hydrogen iodide are preferred, hydrogen chloride and hydrogen bromide are more preferred, and hydrogen bromide is even more preferred.

[0074] Examples of carboxylic acids include formic acid, acetic acid, propionic acid, n-butyric acid, and isobutyric acid. These may be used alone or in combination of two or more. Of these, formic acid and acetic acid are preferred, and acetic acid is more preferred.

[0075] Examples of alcohols include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, trifluoromethanol, and trifluoroethanol. These may be used alone or in combination of two or more. Of these, methanol, ethanol, n-propyl alcohol, and isopropyl alcohol are more preferred.

[0076] As the Bronsted acid, hydrogen chloride, hydrogen bromide, hydrogen iodide, water, acetic acid, methanol, ethanol, and isopropyl alcohol are preferred, hydrogen chloride, hydrogen bromide, and hydrogen iodide are more preferred, hydrogen chloride and hydrogen bromide are still more preferred, and hydrogen bromide is particularly preferred.

[0077] The gas containing a Bronsted acid is not particularly limited as long as it contains a Bronsted acid, but may contain an inert gas in addition to the Bronsted acid. Examples of the inert gas are as described above.

[0078] The content of the Bronsted acid in 100% by volume of the gas containing the Bronsted acid can be, for example, 10 to 100% by volume. In this case, the content of the inert gas in 100% by volume of the gas containing the Bronsted acid can be, for example, 0 to 90% by volume.

[0079] In 100% by volume of the gas containing a Brønsted acid, the total content of the Brønsted acid 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, particularly preferably 98% by volume or more, and may be 100% by volume.

[0080] The volume ratio of the hydrocarbon group-containing phosphine to the Brønsted acid may be such that hydrocarbon group-containing phosphine:Brønsted acid = 1:0.01 or more and 1:100 or less, or hydrocarbon group-containing phosphine:Brønsted acid = 1:0.1 or more and 10 or less, or hydrocarbon group-containing phosphine:Brønsted acid = 1:0.1 or more and 1 or less. This tends to more suitably obtain the effects of the present disclosure.

[0081] In the dry etching method of the present disclosure, it is preferable to bring the hydrocarbon group-containing phosphine and the Bronsted acid into contact with the film to be etched in a non-plasma environment without a plasma state, 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.

[0082] The etching temperature is preferably 100° C. or higher, more preferably 150° C. or higher, even more preferably 200° C. or higher, and particularly preferably 300° C. or higher, because it allows for more suitable etching of the film containing a metal element, and is preferably 500° C. or lower, more preferably 400° C. or lower, and even more preferably 350° C. or lower, because it allows for more suitable suppression of damage to the silicon-containing film. The etching temperature may be 300° C. or lower, 275° C. or lower, 250° C. or lower, 225° C. or lower, 200° C. or lower, or 175° C. or lower.

[0083] [First Dry Etching Method] The following describes a first dry etching method of the present disclosure, in which a gas containing the hydrocarbon group-containing phosphine and a gas containing the Brønsted acid are simultaneously brought into contact with a film to be etched. In the first dry etching method, a gas A containing a gas containing the hydrocarbon group-containing phosphine and a gas containing the Brønsted acid is brought into contact with the film to be etched. Gas A contains at least a hydrocarbon group-containing phosphine and a Brønsted acid.

[0084] The hydrocarbon group-containing phosphine and Bronsted acid contained in gas A are as described above, including preferred embodiments.

[0085] The amount of hydrocarbon group-containing phosphine contained in Gas A (the content of hydrocarbon group-containing phosphine in 100% by volume of Gas A) is preferably 5 to 99% by volume, and more preferably 10 to 90% by volume. This tends to more suitably achieve the effects of the present disclosure.

[0086] The amount of Brønsted acid contained in gas A (the content of Brønsted acid in 100% by volume of gas A) is preferably 0.1 to 65% by volume, and more preferably 1 to 60% by volume. This tends to more suitably obtain the effects of the present disclosure.

[0087] The volume ratio of the hydrocarbon group-containing phosphine and the Bronsted acid contained in Gas A is as described above.

[0088] Gas A is not particularly limited as long as it contains a hydrocarbon group-containing phosphine and a Bronsted acid, but may also contain an inert gas in addition to the hydrocarbon group-containing phosphine and the Bronsted acid. Examples of the inert gas are as described above.

[0089] The total content of the hydrocarbon group-containing phosphine and the Bronsted acid in 100% by volume of Gas A can be, for example, 10 to 100% by volume. In this case, the content of the inert gas in 100% by volume of Gas A can be, for example, 0 to 90% by volume.

[0090] In 100% by volume of Gas A, the total content of the hydrocarbon group-containing phosphine, the Bronsted acid, 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, particularly preferably 98% by volume or more, and may be 100% by volume.

[0091] In the first dry etching method, the object to be etched is preferably placed in a processing vessel. In the first dry etching method, after contacting Gas A with the film to be etched, a step of reducing the pressure inside the processing vessel is preferably performed. This is because by-products generated during etching can be removed. The reduced pressure state refers to a state in which the pressure inside the processing vessel is lower than the pressure during etching, and generally refers to a pressure of 0.133 kPa or less.

[0092] The first dry etching method preferably includes a step of replacing the atmosphere in the processing vessel with an inert gas after contacting the gas A with the film to be etched. This is because by-products generated during etching can be removed. The first dry etching method may also include a step of replacing the atmosphere in the processing vessel with an inert gas after a step of reducing the pressure in the processing vessel.

[0093] [Second Dry Etching Method] Next, a second dry etching method according to the present disclosure will be described, which includes a first step of contacting the film to be etched with gas B containing the Brønsted acid and a second step of contacting the film to be etched with gas C containing the hydrocarbon group-containing phosphine. Gas B contains at least a Brønsted acid, and gas C contains at least a hydrocarbon group-containing phosphine.

[0094] The Bronsted acid contained in gas B and the hydrocarbon group-containing phosphine contained in gas C are as described above, including preferred embodiments.

[0095] Gas B is not particularly limited as long as it contains a Brønsted acid, but may also contain an inert gas or the like in addition to the Brønsted acid. Gas C is not particularly limited as long as it contains a hydrocarbon group-containing phosphine, but may also contain an inert gas or the like in addition to the hydrocarbon group-containing phosphine. The inert gas is as described above.

[0096] The content of the Bronsted acid in 100% by volume of Gas B can be, for example, 10 to 100% by volume. In this case, the content of the inert gas in 100% by volume of Gas B can be, for example, 0 to 90% by volume. The content of the hydrocarbon group-containing phosphine in 100% by volume of Gas C can be, for example, 10 to 100% by volume. In this case, the content of the inert gas in 100% by volume of Gas C can be, for example, 0 to 90% by volume.

[0097] In 100% by volume of Gas B, the total content of the Brønsted acid 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, particularly preferably 98% by volume or more, and may be 100% by volume. In 100% by volume of Gas C, the total content of the hydrocarbon group-containing phosphine 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, particularly preferably 98% by volume or more, and may be 100% by volume. The volume ratio of the hydrocarbon group-containing phosphine contained in Gas C to the Brønsted acid contained in Gas B is as described above.

[0098] In the second dry etching method, the object to be etched is preferably placed in a processing vessel. In the second dry etching method, after contacting Gas B and Gas C with the film to be etched, the processing vessel is preferably subjected to a reduced pressure state. This is because by-products generated during etching can be removed.

[0099] The second dry etching method preferably includes a step of substituting an inert gas for the atmosphere in the processing vessel after contacting Gas B and Gas C with the film to be etched. This is because by-products generated during etching can be removed. The second dry etching method may include a step of substituting an inert gas for the atmosphere in the processing vessel after a step of reducing the pressure in the processing vessel.

[0100] In the second dry etching method of the present disclosure, the above steps may be repeated multiple times to repeatedly etch the film to be etched. Since it is possible to etch the film to a certain thickness in one etching step cycle, by specifying the number of cycles, it is possible to precisely etch a layer to a desired thickness.

[0101] (First Dry Etching Method Using Etching Apparatus) The first dry etching method can be realized, for example, by using an etching apparatus shown in FIG. 1 . FIG. 1 is a schematic diagram of an etching apparatus used in the examples of the present disclosure. The first dry etching method will be specifically described below using the etching apparatus of FIG. 1 as an example. The etching apparatus of the present disclosure includes a mounting table on which a workpiece is placed, a hydrocarbon group-containing phosphine gas supply unit that supplies a gas containing a hydrocarbon group-containing phosphine to the workpiece, and a Brønsted acid gas supply unit that supplies a gas containing a Brønsted acid to the workpiece. The etching apparatus of the present disclosure may further include an inert gas supply unit that supplies an inert gas to the workpiece.

[0102] In the first dry etching method, a gas A containing a gas containing a hydrocarbon group-containing phosphine (also simply referred to as hydrocarbon group-containing phosphine gas) and a gas containing a Brønsted acid (also simply referred to as Brønsted acid gas) is brought into contact with a film to be etched. First, a workpiece 10 having a film to be etched containing a metal, an oxide of the metal, or a nitride of the metal formed thereon is placed on a mounting portion 111 in a processing vessel 110. Next, the interior of the processing vessel 110, the pipe 121, the pipes 131 and 132, the pipes 141 and 142, the pipes 151 and 152, the liquid nitrogen trap 194, and the pipe 191 are evacuated to a predetermined pressure by a vacuum pump 193, and then the workpiece 10 is heated by a heating means 190.

[0103] When the workpiece 10 reaches a predetermined temperature, the hydrocarbon group-containing phosphine gas supply unit 130 and the Brønsted acid gas supply unit 140 supply the hydrocarbon group-containing phosphine gas and the Brønsted acid gas at predetermined flow rates to the pipe 121. The hydrocarbon group-containing phosphine gas supply unit 130 adjusts the supply rate using valves V1 and V2 and flow rate adjustment unit MFC1, and supplies the hydrocarbon group-containing phosphine gas from pipes 131 and 132 to the pipe 121. The Brønsted acid gas supply unit 140 adjusts the supply rate using valves V3 and V4 and flow rate adjustment unit MFC2, and supplies the Brønsted acid gas from pipes 141 and 142 to the pipe 121.

[0104] Alternatively, the inert gas may be supplied at a predetermined flow rate from the inert gas supply unit 150 to the pipe 121. The inert gas supply unit 150 adjusts the supply amount using valves V5 and V6 and a flow rate adjustment unit MFC3, and supplies the inert gas from pipes 151 and 152 to the pipe 121.

[0105] In FIG. 1, PI1 and PI2 are pressure gauges, and the flow rate adjusting means and valves are controlled based on the indicated values.

[0106] The hydrocarbon group-containing phosphine gas and the Brønsted acid gas are mixed in a predetermined composition and supplied to the processing vessel 110. While the mixed gas is being introduced into the processing vessel 110, the pressure inside the processing vessel 110 is controlled to a predetermined value. The gas is reacted with a film to be etched, which contains a metal, an oxide of the metal, or a nitride of the metal, for a predetermined time to form a complex, and etching is performed. This first dry etching method enables plasma-less etching without a plasma state, and does not require excitation of the gas by plasma or the like during etching. The gas flow rate can be appropriately set based on the volume and pressure of the processing vessel, etc.

[0107] Etching accompanied by a plasma state refers to a process in which a gas or the like at, for example, about 0.01 to 1.33 kPa is introduced into a reaction chamber, high-frequency power is applied to an outer coil or an opposing electrode to generate low-temperature gas plasma in the reaction chamber, and etching is performed by the activated chemical species such as ions and radicals that are generated in the reaction chamber. In the dry etching method of the present disclosure, dry etching can be performed by contacting a gas without a plasma state and without generating the above-mentioned gas plasma.

[0108] After the etching is completed, the heating by the heating means 190 is stopped to lower the temperature, and the vacuum pump 193 is stopped and the atmosphere is replaced with an inert gas to release the vacuum. As described above, the dry etching method using the etching apparatus can etch a film to be etched that contains the metal, an oxide of the metal, or a nitride of the metal.

[0109] (Etching Conditions in the First Dry Etching Method) In the first dry etching method, the temperature of the film to be etched during etching is the same as the temperature during the etching described above. The surface temperature of the object to be etched is substantially equal to the temperature of the film to be etched; however, during the etching reaction, the temperature of the surface of the object to be etched or the temperature of the film to be etched may increase due to the heat of reaction. In the present disclosure, it is preferable that at least the temperature during etching, i.e., the temperature inside the processing vessel or the temperature of the mounting portion on which the object to be etched is placed, is within the above-mentioned temperature range. When the heated film to be etched is simultaneously contacted with a gas containing a hydrocarbon group-containing phosphine and a gas containing a Brønsted acid, the metal on the surface of the film to be etched becomes a complex of the metal element, the Brønsted acid-derived anion, and the hydrocarbon group-containing phosphine, and a complex is formed on the surface of the film to be etched. Because this complex has a high vapor pressure, the complex vaporizes, allowing the film to be removed.

[0110] The pressure inside the processing vessel during etching is not particularly limited, but is usually 0.1 kPa to 101.3 kPa.

[0111] In order to obtain a sufficient etching rate, the pressure inside the processing chamber during etching is preferably 2.67 kPa to 39.9 kPa, and more preferably 2.67 kPa to 26.7 kPa.

[0112] The etching time is not particularly limited, but is preferably within 60 minutes in consideration of the efficiency of the semiconductor device manufacturing process. Here, the etching time refers to the time from when a gas is introduced into a processing vessel in which a workpiece is placed until the mixed gas in the processing vessel is exhausted by a vacuum pump or the like to complete the etching process.

[0113] (Second Dry Etching Method Using Etching Apparatus) The second dry etching method can be realized, for example, by using the etching apparatus shown in Fig. 1. The second dry etching method will be specifically described below using the etching apparatus shown in Fig. 1 as an example.

[0114] In the second dry etching method, the gas B containing the Bronsted acid is brought into contact with the film to be etched, and then the gas C containing the hydrocarbon group-containing phosphine is brought into contact with the film to be etched.

[0115] First, the object 10 to be processed, on which a film to be etched containing a metal, an oxide of the metal, or a nitride of the metal is formed, is placed on the mounting portion 111 in the processing vessel 110. Next, the inside of the processing vessel 110, the pipe 121, the pipes 131 and 132, the pipes 141 and 142, the pipes 151 and 152, the liquid nitrogen trap 194, and the pipe 191 are evacuated to a predetermined pressure by the vacuum pump 193, and then the object 10 to be processed is heated by the heating means 190.

[0116] When the workpiece 10 reaches a predetermined temperature, first, a Brønsted acid gas, which is gas B, is supplied from the Brønsted acid gas supply unit 140 to the pipe 121 at a predetermined flow rate. Alternatively, an inert gas may be supplied from the inert gas supply unit 150 to the pipe 121 at a predetermined flow rate. While the Brønsted acid gas, which is gas B, is being introduced into the processing vessel 110, the pressure inside the processing vessel 110 is controlled to a predetermined pressure. By introducing the gas B into the processing vessel 110 for a predetermined time, the Brønsted acid gas is adsorbed onto the film to be etched.

[0117] After evacuating gas B containing a Bronsted acid gas, hydrocarbon group-containing phosphine gas, which is gas C, is supplied from hydrocarbon group-containing phosphine gas supply unit 130 to pipe 121 at a predetermined flow rate. Alternatively, an inert gas may be supplied from inert gas supply unit 150 to pipe 121 at a predetermined flow rate. While introducing hydrocarbon group-containing phosphine gas, which is gas C, into processing vessel 110, the pressure inside processing vessel 110 is controlled to a predetermined pressure. By introducing gas C into processing vessel 110 for a predetermined time, the film to be etched can be etched.

[0118] In the second dry etching method of the present disclosure, a cycle consisting of a first step of introducing a Brønsted acid gas into the processing vessel 110 and a second step of introducing a hydrocarbon group-containing phosphine gas into the processing vessel 110 can be repeated multiple times. In the second dry etching method of the present disclosure, the thickness of the film to be etched in one cycle can be controlled by setting the etching conditions for one cycle to predetermined conditions. Therefore, by setting the thickness of the film to be etched in one cycle to a thin value, the thickness to be etched can be precisely controlled. In the second dry etching method of the present disclosure, the first step is preferably performed followed by the second step. Furthermore, it is preferable to perform a step of reducing the pressure inside the processing vessel or a step of replacing the atmosphere inside the processing vessel with an inert gas after each cycle. After the first step, a step of reducing the pressure inside the processing vessel or a step of replacing the atmosphere inside the processing vessel with an inert gas may be performed.

[0119] The second dry etching method also allows for plasma-less etching, which does not involve a plasma state, and does not require excitation of the etching gas with plasma, etc. The flow rates of the hydrocarbon group-containing phosphine gas and the Brønsted acid gas can be appropriately set based on the volume and pressure of the processing vessel, etc.

[0120] In this way, in the second dry etching method using the above-mentioned etching apparatus, the gas can be brought into contact with the film to be etched without creating a plasma state, and dry etching can be performed without generating the above-mentioned gas plasma.

[0121] After the etching process is completed, the heating by the heating means 190 is stopped to lower the temperature, and the vacuum pump 193 is stopped and replaced with an inert gas to release the vacuum. In this way, the film to be etched can be etched.

[0122] (Etching Conditions in the Second Dry Etching Method) In the second dry etching method, the temperature of the film to be etched when the first step is performed and the temperature of the film to be etched when the second step is performed are the same as the temperatures during the etching described above.

[0123] Furthermore, when Gas B is brought into contact with the film to be etched, and when Gas C is brought into contact with the film to be etched, the pressure inside the processing vessel in which the object to be processed on which the film to be etched is formed is placed is not particularly limited, but is usually 0.1 kPa to 101.3 kPa.

[0124] From the viewpoint of obtaining a sufficient etching rate, the pressure inside the processing container when performing the first step and the pressure inside the processing container when performing the second step are preferably 2.67 kPa to 39.9 kPa, and more preferably 2.67 kPa to 26.7 kPa.

[0125] The processing times for the first step and the second step are not particularly limited, but the processing time for one cycle of the first step is preferably 60 minutes or less, and the processing time for one cycle of the second step is preferably 60 minutes or less. Here, the processing time for the etching step refers to the time from when a gas is introduced into a processing vessel in which a workpiece is placed until the gas in the processing vessel is subsequently evacuated by a vacuum pump or the like to complete the etching process.

[0126] <Method for manufacturing a semiconductor device> The dry etching method of the present disclosure described above can be used as an etching method for forming a predetermined pattern in a film containing a metal element in a semiconductor device. A semiconductor device can be manufactured by etching a film containing a metal element on a substrate using the dry etching method of the present disclosure. The method for manufacturing a semiconductor device of the present disclosure is characterized by including a step of applying the dry etching method of the present disclosure to a film containing a metal element on a substrate to etch the film. The step of supplying a gas containing a hydrocarbon group-containing phosphine and a gas containing a Brønsted acid to the film to etch the film can be performed by the dry etching method of the present disclosure described above.

[0127] <Cleaning Method> The cleaning method disclosed herein is characterized by removing metal-element-containing deposits deposited on the surface of a processing vessel of a substrate processing apparatus using a hydrocarbon group-containing phosphine and a Brønsted acid. The conditions and procedures for contacting the deposits deposited on the surface of the processing vessel in the processing vessel of the substrate processing apparatus with a gas containing a hydrocarbon group-containing phosphine and a gas containing a Brønsted acid, and the deposits, are similar to the conditions and procedures for contacting the film to be etched with a gas containing a hydrocarbon group-containing phosphine and a gas containing a Brønsted acid, and the film to be etched, in the above-mentioned dry etching method. In the cleaning method disclosed herein, it is preferable to contact the hydrocarbon group-containing phosphine and the Brønsted acid with the deposits without using a plasma state. The temperature of the deposits during gas contact is not particularly limited and is similar to the temperature during etching described above.

[0128] Examples of the present disclosure will be listed below together with comparative examples, but the present disclosure is not limited to the following examples.

[0129] [Examples 1 to 18] Using a simultaneous differential thermal analysis (TG-DTA) device, indium oxide (In ２ O ３ ), tin oxide (SnO), zinc oxide (ZnO), zirconium oxide (ZrO ２ ), hafnium oxide (HfO ２ ), aluminum oxide (Al ２ O ３ ), silicon oxide (SiO ２ After the powder sample was introduced into the apparatus, HCl was added at 5 sccm, P(Me) ３ Measurements were performed by flowing trimethylphosphine (Trimethylphosphine) at 10 sccm, controlling the pressure to a predetermined level, and raising the temperature to 400°C at a rate of 10°C / min. The results are shown in Table 1. The etching rate (mass % / min) was calculated from the slope of the tangent to the weight loss rate at each temperature, and was calculated from the measurement results at two points at a predetermined temperature using the following formula: Etching rate (mass % / min) = [(weight loss rate at point (2)) - (weight loss rate at point (1))] / [(elapsed time of measurement at point (2)) - (elapsed time of measurement at point (1)].

[0130]

[0131] From Table 1, HCl and P(Me) ３ By using In ２ O ３ , SnO, ZnO, ZrO ２ , HfO ２ , Al ２ O ３ It was found that etching proceeded for the powder sample of SiO. ２ Since etching does not proceed on SiO ２ It was found that etching can be performed without damaging the surface.

[0132] [Comparative Examples 1 to 13] Additive gas changed from HCl to SO ２ Cl ２ Silicon oxide (SiO ２ The results are shown in Table 2.

[0133]

[0134] As is clear from a comparison of Tables 1 and 2, P(Me) ３ and SO ２ Cl ２ When using SiO ２ Etching proceeds against SiO ２ It was found that it was not possible to etch the silicon dioxide without damaging the silicon dioxide.

[0135] Examples 19 to 21 were carried out using the same apparatus and procedures as in Examples 1 to 18, except that the additive gas was changed from HCl to HBr. The results are shown in Table 3.

[0136]

[0137] As is clear from a comparison of Tables 1 and 3, in the present disclosure, by using HBr as a Bronsted acid, the amount of In was reduced compared to when HCl was used. ２ O ３ It was found that the etching rate of

[0138] [Examples 22 to 29] Additive gas was CH３ COOH, CH ３ OH, CH ３ CH ２ The same equipment and procedures as in Examples 1 to 18 were used, except that the solvent was changed to ethanol (OH) or isopropyl alcohol (IPA). The results are shown in Table 4.

[0139]

[0140] From Table 4, CH is used as the Brønsted acid. ３ COOH, CH ３ OH, CH ３ CH ２ When OH or IPA is used, SiO ２ Without damaging the ２ O ３ It was found that etching of the same In was possible. ２ O ３ It was found that when hydrogen halide was used in Examples 1 to 3 and 19 to 21, etching proceeded at a low temperature of less than 300°C.

[0141] Examples 30 to 32 were carried out using the same equipment and procedures as in Examples 1 to 18, except that triethylphosphine was used instead of trimethylphosphine. The results are shown in Table 5.

[0142]

[0143] From Table 5, when triethylphosphine was used, SiO ２ Without damaging the ２ O ３ It was found that etching of

[0144] As described above, the dry etching method of the present disclosure is a dry etching method for etching a film containing a metal element using a hydrocarbon group-containing phosphine and a Brønsted acid, and therefore it has been found that it is possible to etch a film containing a metal element. Furthermore, it has also been found that the dry etching method of the present disclosure can etch a film containing a metal element while suppressing damage to a silicon-containing film.

[0145] REFERENCE SIGNS LIST 10 Object to be processed 100 Etching apparatus 110 Processing container 111 Mounting section 121 Pipe 130 Hydrocarbon group-containing phosphine gas supply section 131, 132 Pipe 140 Bronsted acid gas supply section 141, 142 Pipe 150 Inert gas supply section 151, 152 Pipe 190 Heating means 191, 192 Pipe 193 Vacuum pump 194 Liquid nitrogen trap MFC1, MFC2, MFC3 Flow rate adjusting means PI1, PI2 Pressure gauge V1, V2, V3, V4, V5, V6, V7, V8 Valve

Claims

1. A dry etching method in which a film containing a metal element is etched using a hydrocarbon group-containing phosphine and a Bronsted acid.

2. The dry etching method according to claim 1, wherein the Bronsted acid is a compound that, after releasing a proton, becomes at least one anion selected from the group consisting of an anion represented by the following formula (1), an anion represented by the following formula (2), and an anion represented by the following formula (3): X － (1) (In formula (1), X is a halogen atom or a hydroxy group.) RO － (2) (In formula (2), R is a monovalent hydrocarbon group or a monovalent halogenated hydrocarbon group.) RCOO － (3) (In formula (3), R is a hydrogen atom, a monovalent hydrocarbon group, or a monovalent halogenated hydrocarbon group.) 3. The dry etching method according to claim 2, wherein R in said formula (2) and said formula (3) is a monovalent hydrocarbon group having 5 or less carbon atoms or a monovalent halogenated hydrocarbon group having 5 or less carbon atoms.

4. The dry etching method according to claim 1, wherein the Bronsted acid is at least one selected from the group consisting of hydrogen halides, carboxylic acids, alcohols and water.

5. The dry etching method according to claim 1, wherein the Bronsted acid is at least one selected from the group consisting of hydrogen chloride, hydrogen bromide, hydrogen iodide, hydrogen fluoride, water, acetic acid, methanol, ethanol and isopropyl alcohol.

6. The dry etching method according to claim 1, wherein the hydrocarbon group contained in said hydrocarbon-group-containing phosphine is at least one selected from the group consisting of a methyl group, an ethyl group, a cyclohexyl group and a phenyl group.

7. The dry etching method according to claim 1, wherein the hydrocarbon group-containing phosphine is at least one selected from the group consisting of trimethylphosphine, triethylphosphine, tricyclohexylphosphine and triphenylphosphine.

8. The dry etching method according to claim 1, wherein the film to be etched is a film to be etched that contains a metal containing at least one selected from the group consisting of In, Sn, Zn, Ga, Hf, Zr, Al, Ta, Ti, Fe, Co, and Ni, an oxide of the metal, or a nitride of the metal.

9. The dry etching method according to claim 1, wherein the film to be etched is a film to be etched that contains a metal containing at least one selected from the group consisting of In, Sn, Zn, Hf, Al and Zr, an oxide of the metal, or a nitride of the metal.

10. The dry etching method according to claim 1, wherein the etching temperature is 100°C or higher.

11. The dry etching method according to claim 1, wherein a gas A containing the hydrocarbon group-containing phosphine and the Bronsted acid is brought into contact with the film to be etched.

12. A dry etching method according to claim 11, wherein the amount of said hydrocarbon group-containing phosphine contained in said gas A is 5 to 99% by volume.

13. A dry etching method according to claim 11, wherein the amount of said Bronsted acid contained in said gas A is 0.1 to 65% by volume.

14. A dry etching method according to claim 1, comprising a first step of contacting the film to be etched with gas B containing the Bronsted acid, and a second step of contacting the film to be etched with gas C containing the hydrocarbon group-containing phosphine.

15. The dry etching method according to claim 1, wherein the film to be etched containing a metal element is selectively etched relative to a silicon-containing film.

16. A cleaning method for removing deposits containing metal elements deposited on the surface of a processing vessel of a substrate processing apparatus using a hydrocarbon group-containing phosphine and a Bronsted acid.

17. A method for manufacturing a semiconductor device, comprising the step of applying the dry etching method according to any one of claims 1 to 15 to a film containing a metal element on a substrate, thereby etching the film.

18. An etching apparatus comprising: a mounting table for mounting an object to be processed; a hydrocarbon group-containing phosphine gas supply unit for supplying a gas containing a hydrocarbon group-containing phosphine to the object to be processed; and a Bronsted acid gas supply unit for supplying a gas containing a Bronsted acid to the object to be processed.

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