Etching method, method for manufacturing semiconductor device, etching device, surface treatment gas composition, and etching gas composition containing surface treatment material

Abstract

The present invention provides: an etching method with which it is possible to selectively etch a film that contains Si and O but does not contain N; a method for manufacturing a semiconductor device, to the method the etching method being applied; an etching device; a surface treatment gas composition; and an etching gas composition containing a surface treatment material. The present invention relates to an etching method for selectively etching a film that contains Si and O but does not contain N, wherein (I) an etching gas composition that contains an HF gas, and (II) a surface treatment gas composition that contains a surface treatment material are brought into contact with a substrate which has a film that contains at least Si and O but does not contain N and a film that contains at least Si and N.

Description

Etching method, semiconductor device manufacturing method, etching apparatus, surface treatment gas composition, and etching gas composition containing surface treatment material

[0001] The present disclosure relates to an etching method, a method for manufacturing a semiconductor device, an etching apparatus, a surface treatment gas composition, and an etching gas composition containing a surface treatment material.

[0002] In the manufacturing process of semiconductor devices, there is a process of etching silicon oxide films present on the surface of semiconductor wafers, such as CVD oxide films, thermal oxide films, and native oxide films. Methods for etching such silicon oxide films include wet etching using chemical solutions and plasma etching using reactive gas plasma.

[0003] However, wet etching has the problem that chemicals can easily affect materials that are not the target of etching, and plasma etching has the problem that the plasma can cause electrical damage to the wafer.

[0004] To address these problems, attempts have been made to develop dry etching methods that do not use plasma. For example, Patent Document 1 discloses a dry etching method in which silicon oxide is reacted with gaseous hydrogen fluoride and gaseous organic amine compound without using a plasma state.

[0005] International Publication No. 2020 / 054476

[0006] The method described in Patent Document 1 is capable of dry etching silicon oxide without using a plasma state. However, as a result of extensive research by the present inventors, it has been found that there is room for improvement in terms of selectively etching a film that contains Si and O but does not contain N.

[0007] The present disclosure aims to solve the above-mentioned problems newly discovered by the present inventors, and to provide an etching method capable of selectively etching a film containing Si and O but not N, a semiconductor device manufacturing method applying the etching method, an etching apparatus, a surface treatment gas composition, and an etching gas composition containing a surface treatment material.

[0008] As a result of intensive research, the present inventors have found that by contacting a substrate having a film containing at least Si and O but not containing N and another film containing at least Si and N with (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material, it is possible to selectively etch the film containing Si and O but not containing N, and have completed the present disclosure.

[0009] That is, the present disclosure (1) relates to an etching method for selectively etching a film containing Si and O but not containing N, by contacting a substrate having a film containing at least Si and O but not containing N and a film containing at least Si and N with (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material.

[0010] The present disclosure (2) relates to the etching method according to the present disclosure (1), in which the surface treatment material chemically modifies the surface of the film containing Si and N.

[0011] The present disclosure (3) relates to the etching method according to the present disclosure (1), in which the surface treatment material chemically modifies the surface of the film containing Si and N and the surface of the film containing Si and O but not N.

[0012] The present disclosure (4) relates to the etching method according to any one of the present disclosures (1) to (3), wherein the surface treatment material is a compound represented by general formula [A]: R-X [A] (in general formula [A], R is a monovalent group, and X is Br, Cl, I, F, —C(O)Cl, —C(O)F, —C(O)H, or —NCO).

[0013] The present disclosure (5) relates to the etching method according to the present disclosure (4), in which R in the general formula [A] is a group that does not react with HF.

[0014] The present disclosure (6) relates to the etching method according to the present disclosure (5), in which R in the general formula [A] is a group that does not contain an amino group and / or a hydroxyl group.

[0015] The present disclosure (7) relates to the etching method according to the present disclosure (4), in which R in the general formula [A] is an electron-withdrawing group.

[0016] The present disclosure (8) is a compound in which R in the general formula [A] is XSO ２ - (X is a halogen atom), XCO- (X is a halogen atom), or C ｎ R １ ２ｎ＋１ SO ２ - (R １ are the same or different and are a hydrogen atom or a halogen atom, and n is an integer of 6 or less.

[0017] The present disclosure (9) is a compound in which R in the general formula [A] is FSO ２ -, FCO-, CF ３ SO ２ - or CH ３ SO ２ - The etching method according to the present disclosure (7).

[0018] The present disclosure (10) is a compound in which R in the general formula [A] is C ｎ R ２ ２ｎ＋１ - (R ２ are the same or different and are a hydrogen atom or a halogen atom, and n is an integer of 6 or less. ｎ R ３ ２ｎ＋１ ) ３ Si-(R ３ are the same or different and are a hydrogen atom or a halogen atom, and n is an integer of 6 or less.

[0019] The present disclosure (11) is a compound in which R in the general formula [A] is an alkyl group having 6 or less carbon atoms, or (CH ３ ) ３ The etching method according to the present disclosure (4) is Si-.

[0020] The present disclosure (12) is that the etching gas composition further contains an inert gas, NH ３ The present disclosure relates to an etching method according to any one of (1) to (11), which comprises at least one selected from the group consisting of an organic amine compound and an alcohol.

[0021] The present disclosure (13) relates to the etching method according to any one of the present disclosures (1) to (12), which selectively etches the film containing Si and O but not N without involving a plasma state.

[0022] The present disclosure (14) relates to the etching method according to any one of the present disclosures (1) to (13), in which the etching gas composition containing (I) HF gas and the surface treatment gas composition containing (II) a surface treatment material are simultaneously brought into contact with the substrate.

[0023] The present disclosure (15) relates to the etching method according to any one of the present disclosures (1) to (13), which includes: (II) a surface treatment step of bringing a surface treatment gas composition containing a surface treatment material into contact with the substrate; and (I) an etching step of bringing an etching gas composition containing HF gas into contact with the substrate after the surface treatment step.

[0024] The present disclosure (16) relates to the etching method according to any one of the present disclosures (1) to (15), in which the substrate temperature during etching is 20 to 300°C.

[0025] The present disclosure (17) relates to the etching method according to any one of the present disclosures (1) to (16), wherein the pressure during etching is 1 Pa to 10 kPa.

[0026] The present disclosure (18) relates to the etching method according to any one of the present disclosures (1) to (17), in which the pressure during etching is 1 Pa or more and less than 1 kPa.

[0027] The present disclosure (19) relates to the etching method according to any one of the present disclosures (1) to (18), in which the film containing Si and O but not N is a silicon oxide (SiO) film.

[0028] The present disclosure (20) relates to the etching method according to any one of the present disclosures (1) to (19), wherein the film containing Si and N is a silicon nitride (SiN) film.

[0029] The present disclosure (21) relates to the etching method according to any one of the present disclosures (1) to (20), wherein, on the substrate, the film containing Si and O but not N is a silicon oxide (SiO) film, the film containing Si and N is a silicon nitride (SiN) film, the silicon nitride film is adjacent to the silicon oxide film, and the silicon oxide film and the silicon nitride film are exposed.

[0030] The present disclosure (22) relates to a method for manufacturing a semiconductor device, comprising a step of selectively etching a film containing Si and O but not containing N by applying the etching method according to any one of the present disclosures (1) to (21) to a substrate having a film containing at least Si and O but not containing N and a film containing at least Si and N.

[0031] The present disclosure (23) relates to a method for manufacturing a semiconductor device, comprising a step of selectively etching a silicon oxide film by applying the etching method according to any one of the present disclosures (1) to (21) to a substrate having a silicon nitride film and a silicon oxide film.

[0032] The present disclosure (24) relates to an etching apparatus comprising: a mounting table for mounting a substrate; (I) an HF gas supply unit for supplying HF gas to the substrate; and (II) a surface treatment gas supply unit for supplying a surface treatment gas composition containing a surface treatment material to the substrate.

[0033] The present disclosure (25) relates to a surface treatment gas composition comprising a surface treatment material.

[0034] The present disclosure (26) relates to a surface treatment material-containing etching gas composition comprising HF gas and a surface treatment material.

[0035] The etching method of the present disclosure is an etching method in which a substrate having a film containing at least Si and O but not containing N and a film containing at least Si and N is contacted with (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material, thereby selectively etching the film containing Si and O but not containing N. Because the surface treatment gas composition containing (II) the surface treatment material is used together with the etching gas composition containing (I) HF gas, the film containing Si and O but not containing N can be selectively etched.

[0036] The method for manufacturing a semiconductor device according to the present disclosure includes a step of applying the etching method according to the present disclosure to a substrate having a film containing at least Si and O but not containing N and a film containing at least Si and N to selectively etch the film containing Si and O but not containing N, or a step of applying the etching method according to the present disclosure to a substrate having a silicon nitride film and a silicon oxide film to selectively etch a silicon oxide film. Because the method for manufacturing a semiconductor device according to the present disclosure includes a step of etching using the etching method according to the present disclosure, it is possible to selectively etch a film containing Si and O but not containing N (e.g., a silicon oxide film) on a semiconductor substrate, and to manufacture a high-quality semiconductor device.

[0037] The etching apparatus of the present disclosure includes a mounting table for mounting a substrate thereon, (I) an HF gas supply unit for supplying HF gas to the substrate, and (II) a surface treatment gas supply unit for supplying a surface treatment gas composition containing a surface treatment material to the substrate. By using (I) HF gas together with (II) the surface treatment gas composition containing the surface treatment material, a film containing Si and O but not N can be selectively etched.

[0038] The surface treatment gas composition of the present disclosure contains a surface treatment material, and therefore can selectively etch a film that contains Si and O but does not contain N.

[0039] The surface treatment material-containing etching gas composition of the present disclosure contains HF gas and a surface treatment material, and therefore can selectively etch a film that contains Si and O but does not contain N.

[0040] FIG. 1 shows the surface treatment material CF on the SiN film. ３ SO ２ 2 is a schematic diagram showing an example of test results when SiO F (TfF) was contacted. ２ The film is treated with CF, a surface treatment material. ３ SO ２ 3 is a schematic diagram showing an example of a test result when F(TfF) was brought into contact with the etching apparatus according to an embodiment of the present disclosure.

[0041] 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.

[0042] 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."

[0043] <Etching Method> The etching method disclosed herein is characterized in that a substrate having a film containing at least Si and O but not containing N and a film containing at least Si and N is contacted with (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material, thereby selectively etching the film containing Si and O but not containing N.

[0044] As a film containing at least Si and O but not N (also simply referred to as a film containing Si and O), 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), for example, 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.

[0045] As a film containing at least Si and N (also simply referred to as a film containing 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 oxynitride (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. Among these, a silicon nitride film is preferable.

[0046] The process temperature (substrate temperature) at which the film formed on the substrate is brought into contact with the etching gas composition containing (I) HF gas is preferably 20°C to 300°C, more preferably 20°C to 250°C, and even more preferably 20°C to 200°C. From the viewpoint of more suitably being able to selectively etch a film containing Si and O, the temperature is preferably 130°C to 250°C, and more preferably 160°C to 230°C. Furthermore, from the viewpoint of suppressing damage to the film formed on the substrate, the temperature may be 20°C to 200°C, 30°C to 150°C, or 50°C to 120°C. The process temperature at which the film formed on the substrate is brought into contact with the surface treatment gas composition containing (II) a surface treatment material, and the process temperature at which the film formed on the substrate is simultaneously brought into contact with the etching gas composition containing (I) HF gas and the surface treatment gas composition containing (II) a surface treatment material, are also preferably the above-mentioned temperatures.

[0047] The etching method of the present disclosure preferably selectively etches the film containing Si and O without using a plasma state, because if the substrate is a semiconductor device substrate, contact with the plasma gas may cause electrical damage to the substrate due to the plasma gas.

[0048] The etching method of the present disclosure is suitable for selectively etching a film containing Si and O. In the etching method of the present disclosure, etching is preferably performed selectively on a film containing Si and O, and etching on a film containing Si and N is preferably performed at a rate of 1.0 nm / min or less. More preferably, the rate is 0.5 nm / min or less. In this specification, "selectively etching a film containing Si and O" means that the ratio of the etching rates of a film containing Si and O to a film containing Si and N (film containing Si and O / film containing Si and N) is 2 or more. The etching rate ratio is preferably 5 or more, more preferably 10 or more, even more preferably 15 or more, particularly preferably 30 or more, most preferably 100 or more, more preferably 350 or more, and even most preferably 400 or more. The upper limit is not particularly limited, but is, for example, 10,000 or less. In this specification, the etching rate is a value calculated based on the flow time of the etching gas by measuring the film thickness before and after the etching process using a spectroscopic ellipsometer.

[0049] In the etching method of the present disclosure, etching of a film containing Si and O is preferably carried out at a rate of 1.5 nm / min or more, more preferably 10 nm / min or more, even more preferably 30 nm / min or more, and particularly preferably 50 nm / min or more, with no particular upper limit, for example, 10 μm / min or less. This tends to more suitably enable selective etching of a film containing Si and O.

[0050] In the etching method of the present disclosure, the substrate is preferably a semiconductor device substrate, and examples thereof include a silicon substrate, a compound semiconductor substrate, a quartz substrate, and a glass substrate. In addition to the film containing at least Si and O and the film containing at least Si and N, a polycrystalline silicon film, a film containing a metal nitride, a silicon film, a metal wiring film, and the like may be formed on the surface of the substrate. A preferred embodiment of the etching method of the present disclosure is one in which the silicon nitride film is adjacent to the silicon oxide film, and the silicon oxide film and the silicon nitride film are exposed. A preferred embodiment of the etching method of the present disclosure is one in which the silicon nitride film is adjacent to the silicon oxide film and the polycrystalline silicon film, and the silicon oxide film, the polycrystalline silicon film, and the silicon nitride film are exposed. The substrate is placed on, for example, a mounting table of an etching apparatus described below, and the mounting table is heated to heat the substrate, as well as the film containing Si and O and the film containing Si and N formed on the surface of the substrate.

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

[0052] In the etching method of the present disclosure, the substrate is preferably placed in a chamber and the etching is performed. The etching method of the present disclosure preferably includes a step of subjecting the chamber to a reduced pressure state. More preferably, the etching method of the present disclosure includes a step of contacting (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material with a substrate having a film containing at least Si and O and a film containing at least Si and N in the chamber, and then subjecting the chamber to a reduced pressure state. This is because by-products generated during etching can be removed. The reduced pressure state refers to a state in which the pressure in the chamber is lower than the pressure (process pressure) during etching, and generally means 0.133 kPa or less.

[0053] The etching method of the present disclosure preferably includes a step of replacing the atmosphere inside the chamber with an inert gas. The etching method of the present disclosure more preferably includes a step of replacing the atmosphere inside the chamber with an inert gas after contacting (I) an etching gas composition containing HF gas with (II) a surface treatment gas composition containing a surface treatment material. This is because by-products generated during etching can be removed. The etching method of the present disclosure may include a step of replacing the atmosphere inside the chamber with an inert gas after a step of subjecting the chamber to a reduced pressure state. For example, since oxide films, oxynitride films, etc. are usually formed on the surface of SiN, which is an example of a film containing Si and N, the etching method of the present disclosure may include a step of removing these films before contacting (I) an etching gas composition containing HF gas with (II) a surface treatment gas composition containing a surface treatment material with a substrate.

[0054] <<(I) Etching Gas Composition Containing HF Gas>> The etching gas composition (I) is not particularly limited as long as it contains HF gas, and may contain 100% by volume of HF gas in 100% by volume of the etching gas composition (I). However, the etching gas composition (I) may further contain an inert gas, NH ３ , an organic amine compound, and an alcohol, ３ It is more preferable that the etching solution contains at least one selected from the group consisting of an organic amine compound and an alcohol, and it is even more preferable that the etching solution contains at least one selected from the group consisting of an organic amine compound and an alcohol, and it is particularly preferable that the etching solution contains an organic amine compound. This tends to more suitably enable selective etching of a film containing Si and O. These may be used alone or in combination of two or more.

[0055] 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. Among these, Ar is preferred because it is stable and inexpensive.

[0056] As the organic amine compound, compounds represented by the following general formula (1) can be used. These may be used alone or in combination of two or more kinds. (In general formula (1), N is a nitrogen atom. R １ is a hydrocarbon group having 1 to 10 carbon atoms, which may have a ring, a hetero atom, or a halogen atom. ２ , R ３ is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, which may have a ring, a heteroatom, or a halogen atom. However, when the hydrocarbon group has 3 or more carbon atoms, it may have a branched or cyclic structure. The heteroatom of the hydrocarbon group is a nitrogen atom, an oxygen atom, a sulfur atom, or a phosphorus atom. Furthermore, R １ and R ２ When both are hydrocarbon groups having one or more carbon atoms, R １ and R ２ may be directly bonded to form a cyclic structure. １ or R ２ are directly bonded to each other via a double bond to form a cyclic structure, R ３ may be absent to form an aromatic ring. １ , R ２ and R ３ may be the same hydrocarbon group or different hydrocarbon groups.)

[0057] R １ Examples of R include a methyl group, an ethyl group, a propyl group, and a butyl group, and some of the hydrogen atoms constituting these organic groups may be substituted with halogens such as fluorine and chlorine. ２ and R ３ Examples of the organic amine include a hydrogen atom, a methyl group, an ethyl group, a propyl group, and a butyl group, and some or all of the hydrogen atoms constituting these organic groups may be substituted with halogen atoms such as fluorine and chlorine. The organic amine represented by the general formula (1) may be a heterocyclic amine having a five-membered ring structure or a six-membered ring structure.

[0058] Specific examples of the organic amine compound include monomethylamine, dimethylamine, trimethylamine, dimethylethylamine, diethylmethylamine, monoethylamine, diethylamine, triethylamine, mono-normal propylamine, di-normal propylamine, monoisopropylamine, diisopropylamine, monobutylamine, dibutylamine, mono-tertiary butylamine, di-tertiary butylamine, pyrrolidine, piperidine, piperazine, pyridine, pyrazine, etc. Further specific examples include compounds in which some or all of the C—H bonds of the above compounds are replaced with C—F bonds (trifluoromethylamine, 1,1,1-trifluorodimethylamine, perfluorodimethylamine, 2,2,2-trifluoroethylamine, perfluoroethylamine, bis(2,2,2-trifluoroethyl)amine, perfluorodiethylamine, 3-fluoropyridine, etc.). These organic amine compounds are preferred in that the pKa of the conjugate acid is 3.2 or more that of HF, they can form salts with hydrogen fluoride, they have a constant vapor pressure in the temperature range of 20 to 100°C, and further they do not decompose in this temperature range and can be supplied as a gas.

[0059] In particular, from the viewpoint of easy availability, monomethylamine, dimethylamine, trimethylamine, monoethylamine, monopropylamine, isopropylamine, 1,1,1-trifluorodimethylamine, 2,2,2-trifluoroethylamine, and bis(2,2,2-trifluoroethyl)amine are preferred as the organic amine compound.

[0060] In addition, secondary amines and tertiary amines are preferred as the organic amine compound because they have a high etching rate for films containing Si and O, such as silicon oxide. Specific examples of secondary amines include dimethylamine, diethylamine, di-normal propylamine, diisopropylamine, dibutylamine, and di-tertiary butylamine. Specific examples of tertiary amines include trimethylamine, dimethylethylamine, diethylmethylamine, and triethylamine.

[0061] Examples of alcohols include methanol, ethanol, 1-propanol, isopropyl alcohol, etc. These may be used alone or in combination of two or more.

[0062] The content of HF gas in 100% by volume of the etching gas composition (I) may be 100% by volume, but is preferably 10 to 90% by volume, more preferably 20 to 80% by volume, further preferably 30 to 70% by volume, and particularly preferably 40 to 60% by volume. ３ , organic amine compounds, or alcohol content (when two or more of these are used in combination, inert gas, NH ３ The total content of the organic amine compound and the alcohol is preferably 10 to 90% by volume, more preferably 20 to 80% by volume, even more preferably 30 to 70% by volume, and particularly preferably 40 to 60% by volume. When the gas composition of the etching gas composition (I) is within the above range, there is a tendency that a film containing Si and O can be selectively etched more suitably. In 100% by volume of the etching gas composition (I), HF gas, an inert gas, NH ３ The total content of the organic amine compound and the alcohol 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 this specification, the content of each gas component in the gas composition can be measured by infrared spectroscopy.

[0063] <<Surface Treatment Gas Composition Comprising (II) Surface Treatment Material>> The (II) surface treatment material is not particularly limited as long as it is a compound that can treat the surface of a substrate, but is preferably a compound that can chemically modify the surface of a film containing Si and N, and more preferably a compound that can chemically modify the surface of a film containing Si and N and the surface of a film containing Si and O. The surface treatment material may be used alone or in combination of two or more types. In this specification, chemical modification means chemical bonding.

[0064] The surface treatment material preferably chemically modifies the surface of a film containing Si and N, and more preferably chemically modifies the surface of a film containing Si and N and the surface of a film containing Si and O. ３ SO ２ 1 is a schematic diagram showing an example of a test result when the SiN film is contacted with CF (TfF), which is a surface treatment material. ３ SO ２ It can be seen that the surface of the SiN film is chemically modified by contacting it with F (TfF). ２ The film is treated with CF, a surface treatment material. ３ SO ２ 2 is a schematic diagram showing an example of test results when F (TfF) is brought into contact with the SiO ２ The film is treated with CF, a surface treatment material. ３ SO ２ By contacting with F (TfF), SiO ２ It can be seen that the surface of the film is chemically modified. As a result of the study by the present inventors, it is assumed that the surface of a film containing Si and N is chemically modified to reduce its reactivity to HF, thereby inhibiting etching, while the surface of a film containing Si and O is chemically modified to increase its reactivity to HF, thereby promoting etching. Note that even if the surface of a film containing Si and N is chemically modified to a greater extent with a surface treatment material than the surface of a film containing Si and O, it is believed that etching of the film containing Si and O proceeds more rapidly than that of the film containing Si and N due to the etching inhibition and promotion effects described above.

[0065] Specific examples of compounds capable of chemically modifying the surface of a film containing Si and N and the surface of a film containing Si and O include compounds represented by the following general formula [A]. These may be used alone or in combination of two or more: R-X [A] (In general formula [A], R is a monovalent group, and X is Br, Cl, I, F, -C(O)Cl, -C(O)F, -C(O)H, or -NCO.)

[0066] R in the general formula [A] is not particularly limited as long as it is a monovalent group, but is preferably a group that does not react with HF, and more preferably a group that does not contain an amino group and / or a hydroxyl group. This tends to enable chemical modification of the surface of the film containing Si and N and the surface of the film containing Si and O without inhibiting etching of the film containing Si and O by HF gas.

[0067] R in the general formula [A] is preferably an electron-withdrawing group, because it allows for more suitable selective etching of a film containing Si and O. Specific examples of the electron-withdrawing group include XSO. ２ - (X is a halogen atom), XCO- (X is a halogen atom), C ｎ R １ ２ｎ＋１ SO ２ - (R １ are the same or different and each represents a hydrogen atom or a halogen atom, and n is an integer of 6 or less. １ Examples of the halogen atom in R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Of these, a fluorine atom is preferred. １ is preferably a hydrogen atom or a fluorine atom. n is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1. A preferred example of the electron-withdrawing group is FSO ２ -, FCO-, CF ３ SO ２ -, CH ３ SO ２ Among them, FSO ２ -, CF ３ SO ２ - is preferred.

[0068] For the reason that a film containing Si and O can be selectively etched more preferably, R in the general formula [A] is preferably C ｎ R ２ ２ｎ＋１ - (R ２ are the same or different and are a hydrogen atom or a halogen atom, and n is an integer of 6 or less. ｎ R ３ ２ｎ＋１ ) ３ Si-(R ３are the same or different and are a hydrogen atom or a halogen atom, and n is an integer of 6 or less. Specific preferred examples of the group include an alkyl group having 6 or less carbon atoms, (CH ３ ) ３ Si- is an example of R ２ , R ３ The halogen atoms in X, R, and the preferred embodiments thereof are １ The halogen atoms are the same as those in R. ２ , R ３ is preferably a hydrogen atom or a fluorine atom, and more preferably a hydrogen atom. n is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.

[0069] X in general formula [A] is Br, Cl, I, F, —C(O)Cl, —C(O)F, —C(O)H, or —NCO. This allows a chemical reaction to occur with the surface of a film containing Si and N and the surface of a film containing Si and O, thereby enabling chemical modification. Among these, Cl, I, F, —C(O)Cl, and —NCO are preferred, —C(O)Cl and —NCO are more preferred, and —NCO is even more preferred.

[0070] Examples of the compound represented by the general formula [A] include CH ３ I, CH ３ Br, CH ３ Cl, CH ３ F, tBu-NCO, CH ３ NCO, FSO ２ NCO, CF ３ SO ２ NCO, CH ３ COCl, CH ３ COF, CH ３ COH, CF ３ SO ２ F, CF ３ SO ２ Cl, CF ３ SO ２ Br, CF ３ SO ２ I, CH ３ SO ２ F, CH ３ SO ２ Cl, CH ３ SO ２ Br, CH ３ SO２ I, FCOF, FCOCl, FCOBr, FCOI, etc. These may be used alone or in combination of two or more. Among them, CH ３ I, tBu-NCO, FSO ２ NCO, CH ３ COCl, CF ３ SO ２ F, CF ３ SO ２ Cl is preferred, FSO ２ NCO is more preferred.

[0071] The surface treatment gas composition (II) is not particularly limited as long as it contains a surface treatment material, and may contain 100% by volume of the surface treatment material in 100% by volume of the surface treatment gas composition (II). However, the surface treatment gas composition (II) may further contain an inert gas, NH ３ The etching gas composition may contain at least one selected from the group consisting of an HF gas, an organic amine compound, and an alcohol (preferably an inert gas). These may be used alone or in combination of two or more. The inert gas, the organic amine compound, and the alcohol are as described in <<(I) Etching Gas Composition Containing HF Gas>>.

[0072] The content of the surface treatment material in 100% by volume of the surface treatment gas composition (II) is preferably 60% by volume or more, more preferably 80% by volume or more, even more preferably 90% by volume or more, particularly preferably 95% by volume or more, and may be 100% by volume. When the gas composition of the surface treatment gas composition (II) is within the above range, there is a tendency that a film containing Si and O can be more suitably selectively etched.

[0073] [First Etching Method] First, as the etching method of the present disclosure, a first etching method will be described in which the etching gas composition containing (I) HF gas and the surface treatment gas composition containing (II) the surface treatment material are simultaneously brought into contact with the substrate. Hereinafter, the etching gas used in the first etching method will be referred to as a surface treatment material-containing etching gas composition, and the surface treatment material-containing etching gas composition is a mixture of the etching gas composition containing (I) HF gas and the surface treatment gas composition containing (II) the surface treatment material, and contains at least HF gas and the surface treatment material.

[0074] In the following description, the film containing at least Si and O and the film containing at least Si and N are also referred to as the film to be etched. When a heated film to be etched is simultaneously contacted with (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material, the surface treatment material (II) chemically modifies the surface of the film containing Si and N and the surface of the film containing Si and O, whereby the reactivity of the surface of the film containing Si and N to HF is reduced due to the chemical modification, and etching is inhibited, while the reactivity of the surface of the film containing Si and O to HF is improved due to the chemical modification, and etching is promoted, and it is thought that the film containing Si and O of the film to be etched can be selectively etched.

[0075] (I) The etching gas composition containing HF gas, and (II) the surface treatment gas composition containing a surface treatment material are the same as those described above, including preferred embodiments.

[0076] The volume ratio of the etching gas composition containing (I) HF gas to the surface treatment gas composition containing (II) a surface treatment material is preferably 10:0.01-10, more preferably 10:0.05-6, and even more preferably 10:0.3-3, where (I) is the etching gas composition containing HF gas and (II) is the surface treatment gas composition containing a surface treatment material. If the proportion of HF gas is too low, the etching rate tends to decrease, while if it is too high, the etching becomes too expensive. Furthermore, if the proportion of the surface treatment gas composition containing the (II) surface treatment material is too high, etching tends to proceed slowly. Since the surface treatment gas composition containing the (II) surface treatment material is effective even in small amounts, the surface treatment gas composition containing the (II) surface treatment material may be present in an amount of 1 ppm by volume or more per 100% by volume of the etching gas composition containing the surface treatment material.

[0077] The etching gas composition containing a surface treatment material is a mixture of the etching gas composition containing (I) HF gas and the surface treatment gas composition containing (II) a surface treatment material, and contains at least HF gas and a surface treatment material.

[0078] The content of HF gas in 100% by volume of the etching gas composition containing a surface treatment material is preferably 10 to 80% by volume, more preferably 20 to 70% by volume, even more preferably 30 to 60% by volume, and particularly preferably 40 to 50% by volume. The content of the surface treatment material in 100% by volume of the etching gas composition containing a surface treatment material is preferably 1 to 35% by volume, more preferably 2 to 25% by volume, even more preferably 3 to 20% by volume, and particularly preferably 5 to 15% by volume. The content of the inert gas, NH ３ , organic amine compounds, or alcohol content (when two or more of these are used in combination, inert gas, NH ３ The total content of the HF gas, the surface treatment material, the inert gas, the NH 3 gas, and the organic amine compound and the alcohol is preferably 10 to 80% by volume, more preferably 20 to 70% by volume, further preferably 30 to 60% by volume, and particularly preferably 40 to 50% by volume, in 100% by volume of the etching gas composition containing the surface treatment material. ３The total content of the organic amine compound and the alcohol 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. When the gas composition of the etching gas composition containing a surface treatment material is within the above range, there is a tendency that a film containing Si and O can be more suitably selectively etched.

[0079] The first etching method preferably includes a step of simultaneously contacting the substrate with the etching gas composition containing (I) HF gas and the surface treatment gas composition containing (II) the surface treatment material in a chamber, and a step of reducing the pressure inside the chamber, and etching is performed by repeating these steps. Instead of reducing the pressure inside the chamber, a step of replacing the chamber with an inert gas may be performed, or a step of replacing the chamber with an inert gas may be performed after reducing the pressure inside the chamber. In one aspect, the first etching method preferably includes a step of simultaneously contacting the substrate with the etching gas composition containing (I) HF gas and the surface treatment gas composition containing (II) the surface treatment material in a chamber, followed by a step of reducing the pressure inside the chamber and / or a step of replacing the chamber with an inert gas.

[0080] [Second Etching Method] Next, as an etching method of the present disclosure, a second etching method will be described, which includes (II) a surface treatment step of bringing a surface treatment gas composition containing a surface treatment material into contact with the substrate, and (I) an etching step of bringing an etching gas composition containing HF gas into contact with the substrate after the surface treatment step.

[0081] In the surface treatment process, a surface treatment gas composition containing the (II) surface treatment material is contacted with the heated film to be etched. The (II) surface treatment material chemically modifies the surface of the Si- and N-containing film and the surface of the Si- and O-containing film, thereby reducing the reactivity of the Si- and N-containing film to HF and inhibiting etching, while the chemical modification of the Si- and O-containing film increases its reactivity to HF, promoting etching. Then, in the etching process, an etching gas composition containing the (I) HF gas is contacted with the substrate, which is thought to selectively etch the Si- and O-containing film of the film to be etched. In the second etching method of the present disclosure, the process may be repeated multiple times to repeatedly etch the film to be etched. Since etching can be performed to a constant thickness in one etching cycle, a layer of a desired thickness can be precisely etched by specifying the number of cycles.

[0082] (I) The etching gas composition containing HF gas, and (II) the surface treatment gas composition containing a surface treatment material are the same as those described above, including preferred embodiments.

[0083] The second etching method preferably includes a surface treatment step and an etching step performed in a chamber, and further includes a step of reducing the pressure inside the chamber. It is preferable to perform the etching by repeating these steps. Instead of reducing the pressure inside the chamber, a step of replacing the atmosphere inside the chamber with an inert gas may be performed, or a step of replacing the atmosphere inside the chamber with an inert gas may be performed after reducing the pressure inside the chamber. In one embodiment, the second etching method preferably performs a surface treatment step, a step of reducing the pressure inside the chamber and / or a step of replacing the atmosphere inside the chamber with an inert gas, and then performs an etching step, followed by a step of reducing the pressure inside the chamber and / or a step of replacing the atmosphere inside the chamber with an inert gas.

[0084] [Etching Apparatus] The etching method of the present disclosure can be realized, for example, by using the following etching apparatus. Such an etching apparatus also constitutes one aspect of the present disclosure. The etching apparatus of the present disclosure comprises a mounting table for mounting a substrate thereon, an HF gas supply unit for supplying the (I) HF gas to the substrate, and a surface treatment gas supply unit for supplying the (II) surface treatment gas composition containing a surface treatment material to the substrate. The etching apparatus of the present disclosure may further comprise an inert gas supply unit for supplying an inert gas into the chamber. The etching apparatus of the present disclosure may also comprise an NH ３ The apparatus may further include an additional gas supply unit that supplies an organic amine compound or an alcohol into the chamber.

[0085] 3 is a schematic diagram showing an etching apparatus according to an embodiment of the present disclosure. The etching apparatus 100 shown in FIG. 3 includes a chamber 110 in which a substrate 113 is placed, an HF gas supply unit 140 connected to the chamber 110 and supplying HF gas, a surface treatment gas supply unit 150 supplying a surface treatment gas composition containing a surface treatment material, an inert gas supply unit 130 supplying an inert gas, and an NH ３ , an organic amine compound, or an alcohol, and a heating means 111 for heating the chamber 110. Note that the etching apparatus 100 does not necessarily have to include the inert gas supply unit 130 and the additional gas supply unit 160.

[0086] The etching apparatus 100 further includes a control unit (not shown). This control unit is, for example, a computer, and includes a program, a memory, and a CPU. The program incorporates steps for performing a series of operations in the first etching method or the second etching method, and performs the following operations in accordance with the program: adjusting the temperature of the substrate 113, opening and closing the valves of each supply unit, adjusting the flow rate of each gas, adjusting the pressure inside the chamber 110, etc. This program is stored on a computer storage medium, such as a compact disc, a hard disk, a magneto-optical disc, or a memory card, and is installed in the control unit.

[0087] The chamber 110 includes a mounting table 112 for mounting a substrate 113 thereon. The chamber 110 is not particularly limited as long as it is resistant to the HF gas used and can be depressurized to a predetermined pressure, but typically, a general chamber provided in a semiconductor etching apparatus is used. Furthermore, the supply pipe for supplying the etching gas and other piping are also not particularly limited as long as they are resistant to HF gas, and general piping can be used.

[0088] The HF gas supply unit 140 adjusts the supply amount using valves 143 and 144 and a flow rate adjusting means 142 , and supplies HF gas from pipes 141 and 145 to the pipe 121 .

[0089] The surface treatment gas supply unit 150 adjusts the supply amount using valves 153 and 154 and a flow rate adjusting means 152 , and supplies the surface treatment gas composition from pipes 151 and 155 to the pipe 121 .

[0090] The inert gas supply unit 130 adjusts the supply amount using valves 133 and 134 and a flow rate adjusting means 132 , and supplies the inert gas from pipes 131 and 135 to the pipe 121 .

[0091] The additional gas supply unit 160 adjusts the supply amount using valves 163 and 164 and a flow rate adjusting means 162 to supply NH ３ , an organic amine compound, or an alcohol is supplied from pipes 161 and 165 to pipe 161. The additional gas supply unit 160 supplies NH ３ The etching apparatus 100 may have a plurality of additional gas supply units 160.

[0092] A heating means 111 for heating the chamber 110 is disposed outside the chamber 110. A heater (not shown) may be provided inside the mounting table 112 as a second heating means. When multiple mounting tables are disposed in the chamber 110, a heater may be provided for each mounting table, thereby allowing the temperature of the substrates on each mounting table to be individually set to a predetermined temperature.

[0093] A gas exhaust means for exhausting the gas after the reaction is disposed on one side of the chamber 110. A vacuum pump 127 of the gas exhaust means exhausts the gas after the reaction from the chamber 110 via a pipe 122. The gas after the reaction can be recovered by disposing a liquid nitrogen trap (not shown) between the pipe 122 and the vacuum pump 127. Valves 125 and 126 are disposed on the pipes 121 and 122, respectively, to adjust the pressure. In addition, in FIG. 3, PIs 123 and 124 are pressure gauges, and a control unit can control the flow rate adjustment means and the valves based on the indicated values.

[0094] The etching method will be specifically described using the etching apparatus 100 as an example. [First Etching Method Using the Etching Apparatus] In the first etching method of the present disclosure, the substrate is simultaneously contacted with the etching gas composition containing (I) HF gas and the surface treatment gas composition containing (II) the surface treatment material. That is, the HF gas and the surface treatment material-containing etching gas composition containing the surface treatment material are contacted with the film to be etched.

[0095] In the first etching method, first, a substrate 113 on which a film to be etched, including a film containing at least Si and O and a film containing at least Si and N, is formed is placed in the chamber 110. Next, the interior of the chamber 110, pipes 121 and 122, pipes 131 and 135, pipes 141 and 145, and pipes 151 and 155 is evacuated to a predetermined pressure by the vacuum pump 127, and then the substrate 113 is heated by the heating means 111. Once the substrate 113 reaches a predetermined temperature, HF gas and a surface treatment gas composition are supplied to the pipe 121 at predetermined flow rates from the HF gas supply unit 140 and the surface treatment gas supply unit 150. Note that an inert gas may be supplied to the pipe 121 at a predetermined flow rate from the inert gas supply unit 130. Also, NH ３ Alternatively, an organic amine compound or an alcohol may be supplied to the pipe 121 at a predetermined flow rate.

[0096] HF gas and a surface treatment gas composition are mixed at a predetermined composition and supplied to the chamber 110. While the mixed etching gas composition containing a surface treatment material is introduced into the chamber 110, the pressure inside the chamber 110 is controlled to a predetermined value. Etching is performed by reacting the etching gas composition containing a surface treatment material with the film to be etched for a predetermined time. This etching method enables plasma-less etching without a plasma state, and does not require excitation of the etching gas composition containing a surface treatment material with plasma or the like during etching. The flow rate of the etching gas composition containing a surface treatment material can be appropriately set based on the volume and pressure of the chamber, etc.

[0097] 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 reactor, high-frequency power is applied to an outer coil or an opposing electrode to generate low-temperature gas plasma in the reactor, and etching is performed by the activated chemical species such as ions and radicals that are generated in the reactor. In the etching method disclosed herein, a gas is brought into contact without a plasma state, and dry etching is performed without generating the gas plasma.

[0098] After the etching process is completed, the heating by the heating means 111 is stopped to lower the temperature, and the vacuum pump 127 is stopped and the atmosphere is replaced with an inert gas to release the vacuum. As described above, by the first etching method using the etching apparatus, a film containing Si and O of the film to be etched can be selectively etched.

[0099] (Etching Conditions in the First Etching Method) In the first etching method of the present disclosure, the temperature of the film to be etched when the etching gas composition containing a surface treatment material is brought into contact with the film to be etched may be a temperature at which the etching gas composition containing a surface treatment material reacts with a film containing Si and O. In particular, it is preferable that the temperature of the film to be etched to be removed is the above-mentioned process temperature (substrate temperature). The substrate temperature is substantially equal to the temperature of the film to be etched, but during the etching reaction, the temperature of the substrate or the film to be etched may rise due to the heat of reaction. In the present disclosure, it is preferable that at least the process temperature (substrate temperature), i.e., the temperature inside the chamber or the temperature of the mounting table on which the substrate is placed, is within the above-mentioned temperature range.

[0100] Furthermore, when the etching gas composition containing a surface treatment material is brought into contact with a film to be etched, the pressure in a chamber in which a substrate on which the film to be etched has been formed (pressure during etching) is not particularly limited, but is usually in the pressure range of 0.1 Pa to 101.3 kPa.

[0101] Since there is a tendency that a film containing Si and O can be selectively etched more suitably, the pressure in the chamber in the etching step is preferably 1 Pa to 100 kPa, more preferably 1 Pa to 10 kPa, even more preferably 10 Pa or more but less than 1 kPa, and most preferably 100 Pa or more but less than 1 kPa.

[0102] The treatment time of the etching step is not particularly limited, but is preferably within 60 minutes in consideration of the efficiency of the semiconductor device manufacturing process. Here, the treatment time of the etching step refers to the time from when the etching gas composition containing the surface treatment material is introduced into a chamber in which a substrate is placed until the etching gas composition containing the surface treatment material is subsequently evacuated from the chamber by a vacuum pump or the like to complete the etching treatment.

[0103] [Second Etching Method Using the Etching Apparatus] The second etching method of the present disclosure includes (II) a surface treatment step of bringing a surface treatment gas composition containing a surface treatment material into contact with the substrate, and (I) an etching step of bringing an etching gas composition containing HF gas into contact with the substrate after the surface treatment step.

[0104] In the second etching method, first, a substrate 113 having a film containing at least Si and O and a film containing at least Si and N formed thereon is placed in a chamber 110. Next, the inside of the chamber 110, the pipes 121 and 122, the pipes 131 and 135, the pipes 141 and 145, and the pipes 151 and 155 are evacuated to a predetermined pressure by a vacuum pump 127, and then the substrate 113 is heated by a heating means 111.

[0105] When the substrate 113 reaches a predetermined temperature, first, a surface treatment gas composition is supplied from the surface treatment gas supply unit 150 to the pipe 121 at a predetermined flow rate. Alternatively, an inert gas may be supplied from the inert gas supply unit 130 to the pipe 121 at a predetermined flow rate. While the surface treatment gas composition or the surface treatment gas composition and an inert gas are introduced into the chamber 110, the pressure inside the chamber 110 is controlled to a predetermined pressure. By introducing the surface treatment gas composition into the chamber 110 for a predetermined time, the surface treatment gas composition is adsorbed (reacted) with the film to be etched. After evacuating the gas containing the surface treatment gas composition, HF gas is supplied from the HF 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 130 to the pipe 121 at a predetermined flow rate. Alternatively, NH ３ Alternatively, an organic amine compound or alcohol may be supplied to the pipe 121 at a predetermined flow rate. While HF gas or HF gas and another gas are introduced into the chamber 110, the pressure inside the chamber 110 is controlled to a predetermined pressure. By introducing HF gas into the chamber 110 for a predetermined time, a film containing Si and O of the film to be etched can be selectively etched.

[0106] In the second etching method of the present disclosure, a surface treatment step of introducing a surface treatment gas composition into the chamber 110 and an etching step of introducing HF gas into the chamber 110 constitute one cycle, and the steps can be repeated multiple times. In the second 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 etching method of the present disclosure, after the surface treatment step, a step of subjecting the chamber to a reduced pressure state is preferably performed, and then the etching step is performed. Furthermore, a step of subjecting the chamber to a reduced pressure state is preferably performed for each cycle.

[0107] In addition, the second etching method also allows for plasma-less etching without a plasma state, and does not require excitation of the etching gas with plasma, etc. The flow rates of the HF gas and the surface treatment gas composition can be appropriately set based on the volume and pressure of the chamber, etc.

[0108] In this way, in the second etching method of the present disclosure using the etching apparatus, the gas can be brought into contact without a plasma state, and dry etching can be performed without generating the gas plasma described above.

[0109] After the etching process is completed, the heating by the heating means 111 is stopped to lower the temperature, and the vacuum pump 127 is stopped and the atmosphere is replaced with an inert gas to release the vacuum. By the second etching method using the etching apparatus, a film containing Si and O of the film to be etched can be selectively etched.

[0110] (Etching Conditions in the Second Etching Method) In the second etching method of the present disclosure, the temperature of the film to be etched may be (II) the temperature at which a surface treatment gas composition containing a surface treatment material reacts with a film containing Si and N and a film containing Si and O, and (I) the temperature at which an etching gas composition containing HF gas reacts with a film containing Si and O. In particular, it is preferable that the temperature of the film to be etched to be removed is the above-mentioned process temperature (substrate temperature). It is desirable that the temperatures of the film to be etched in the surface treatment step and the etching step are the same. The substrate temperature is substantially equal to the temperature of the film to be etched, but during the etching reaction, the temperature of the substrate or the film to be etched may rise due to the heat of reaction. In the present disclosure, it is preferable that at least the process temperature (substrate temperature), i.e., the temperature in the chamber or the temperature of the mounting table on which the substrate is placed, is within the above-mentioned temperature range.

[0111] The pressure in the chamber in the etching step is the same as the conditions described in the etching conditions for the first etching method. On the other hand, the pressure in the chamber in the surface treatment step is preferably 1 Pa to 100 kPa, more preferably 10 Pa to 10 kPa, and even more preferably 10 Pa to 2 kPa. It may also be 1 kPa to 20 kPa. This tends to more suitably enable selective etching of films containing Si and O.

[0112] The treatment times for the surface treatment step and the etching step are not particularly limited, but the treatment time for one cycle of the surface treatment step is preferably 60 minutes or less, and the treatment time for one cycle of the etching step is preferably 60 minutes or less. Here, the treatment time for the etching step refers to the time from when an etching gas is introduced into a chamber in which a substrate is placed until the etching gas in the chamber is subsequently evacuated by a vacuum pump or the like to complete the etching treatment.

[0113] [Method for manufacturing a semiconductor device] The etching method of the present disclosure described above can be used as a method for selectively etching a film containing Si and O (preferably a silicon oxide film) by applying the etching method to a substrate having a film containing at least Si and O and a film containing at least Si and N (preferably a substrate having a silicon nitride film and a silicon oxide film). By selectively etching a film containing Si and O (preferably a silicon oxide film) on a substrate using the etching method of the present disclosure, semiconductor devices can be manufactured inexpensively. The method for manufacturing a semiconductor device of the present disclosure is characterized by comprising a step of selectively etching a film containing Si and O (preferably a silicon oxide film) by applying the etching method to a substrate having a film containing at least Si and O and a film containing at least Si and N (preferably a substrate having a silicon nitride film and a silicon oxide film). The process of selectively etching the film containing Si and O (preferably the silicon oxide film) without plasma by reacting HF gas and the surface treatment material (II) on a substrate having a film containing at least Si and O and a film containing at least Si and N (preferably a substrate having a silicon nitride film and a silicon oxide film) can be performed by the etching method of the present disclosure described above. The substrate may further have a polycrystalline silicon film. The substrate is preferably a silicon substrate.

[0114] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to these examples. ２ A silicon wafer on which a film was formed was prepared. The film thickness of the substrate to be treated was measured before and after etching using a spectroscopic ellipsometer (manufactured by Nippon Semilab Co., Ltd., product name: SE-2000), and the etching amount and SiO ２ The / SiN selectivity was calculated.

[0115] (Simultaneous Flow Method) [Example 1-1] The etching apparatus 100 shown in FIG. 3 was used. First, a substrate to be processed was placed on a stage in a chamber, and after the chamber was sufficiently evacuated, the temperature of the stage was set to 120°C. The temperature of the substrate was the same as that of the stage, which was essentially equal to the temperature of the film to be etched. Next, N was introduced into the chamber. ２ The gas was passed through the chamber to dry it thoroughly. Then, HF gas, trimethylamine gas, and CH ３ COCl gas was passed through for 1 min. The gas flow rate and pressure inside the chamber were as shown in Table 1. Finally, the chamber was evacuated and N ２ The substrates were removed after the gas was replaced with the gas. The results are shown in Table 1. The substrates were silicon wafers with SiN films formed thereon, SiO ２ All the silicon wafers on which the films were formed were placed in the same chamber and simultaneously etched. The etching gas composition (I) was composed of HF gas and trimethylamine gas, and the CH ３ The surface treatment gas composition (II) is composed of COCl gas, HF gas, trimethylamine gas, and CH ３ The COCl gas constitutes the surface treatment material-containing etching gas composition.

[0116] [Examples 1-2] to [Examples 1-4] and [Comparative Example 1-1] Tests were carried out under the same conditions as in Example 1-1, except that the conditions were changed as shown in Table 1. The results are shown in Table 1.

[0117] (Alternating Flow Method) [Example 2-1] First, a substrate to be processed was placed on a stage in a chamber, and the chamber was fully evacuated, and then the temperature of the stage was set to 120° C. Next, N 2 was introduced into the chamber. ２ (A) After that, CH 3 was introduced into the chamber under the conditions shown in Table 2. ３ After the I gas is circulated, sufficient vacuum is drawn and N ２ (B) Next, HF gas and trimethylamine gas were passed through the chamber under the conditions shown in Table 2, and then the chamber was evacuated sufficiently and replaced with N ２Finally, the substrate to be treated was removed from the chamber. The results are shown in Table 2. The etching rate was determined based on the flow time of the etching gas. The substrates to be treated were silicon wafers with SiN films formed thereon, SiO ２ All the silicon wafers on which the films were formed were placed in the same chamber and processed simultaneously. Conditions not specified were the same as those in Example 1-1.

[0118] [Example 2-2] to [Example 2-24] and [Comparative Example 2-1] to [Comparative Example 2-3] Tests were conducted under the same conditions as in Example 2-1, except that the conditions were changed as shown in Table 2. The results are shown in Table 2.

[0119]

[0120]

[0121] As can be seen from Tables 1 and 2, in the examples in which a substrate having a film containing at least Si and O and a film containing at least Si and N was contacted with (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material, the film containing Si and O could be selectively etched. This demonstrates that the film containing Si and O can be selectively etched by using (I) an etching gas composition containing HF gas together with (II) a surface treatment gas composition containing a surface treatment material.

[0122] REFERENCE SIGNS LIST 100 Etching apparatus 110 Chamber 111 Heating means 112 Mounting table 113 Substrate 121, 122 Pipes 123, 124 PI (pressure gauge) 125, 126 Valves 127 Vacuum pump 130 Inert gas supply unit 131, 135 Pipe 132 Flow rate adjustment unit 133, 134 Valves 140 HF gas supply unit 141, 145 Pipe 142 Flow rate adjustment unit 143, 144 Valves 150 Surface treatment gas supply unit 151, 155 Pipe 152 Flow rate adjustment unit 153, 154 Valves 160 Additional gas supply unit 161, 165 Pipe 162 Flow rate adjustment unit 163, 164 Valves

Claims

1. An etching method for selectively etching a film containing Si and O but not containing N, and a film containing at least Si and N, by contacting a substrate having the film with (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material.

2. The etching method according to claim 1, wherein the surface treatment material chemically modifies the surface of the film containing Si and N.

3. The etching method according to claim 1, wherein the surface treatment material chemically modifies the surface of the film containing Si and N and the surface of the film containing Si and O but not N.

4. The etching method according to claim 1, wherein the surface treatment material is a compound represented by general formula [A]: R-X [A] (In general formula [A], R is a monovalent group, and X is Br, Cl, I, F, -C(O)Cl, -C(O)F, -C(O)H, or -NCO.) 5. The etching method according to claim 4, wherein R in the general formula [A] is a group that does not react with HF.

6. The etching method according to claim 5, wherein R in the general formula [A] is a group that does not contain an amino group and / or a hydroxyl group.

7. The etching method according to claim 4, wherein R in the general formula [A] is an electron-withdrawing group.

8. R in the general formula [A] is XSO ２ - (X is a halogen atom), XCO- (X is a halogen atom), or C ｎ R １ ２ｎ＋１ SO ２ - (R １ The etching method according to claim 7 , wherein are the same or different and are a hydrogen atom or a halogen atom, and n is an integer of 6 or less.

9. R in the general formula [A] is FSO ２ -, FCO-, CF ３ SO ２ - or CH ３ SO ２ The etching method according to claim 7, wherein 10. R in the general formula [A] is C ｎ R ２ ２ｎ＋１ - (R ２ are the same or different and each is a hydrogen atom or a halogen atom, and n is an integer of 6 or less. ｎ R ３ ２ｎ＋１ ) ３ Si-(R ３ The etching method according to claim 4 , wherein, are the same or different, each of which is a hydrogen atom or a halogen atom, and n is an integer of 6 or less.

11. In the general formula [A], R is an alkyl group having 6 or less carbon atoms, or (CH ３ ) ３ The etching method of claim 4, wherein the silicon-containing layer is Si-.

12. The etching gas composition further comprises an inert gas, NH ３ 2. The etching method according to claim 1, further comprising at least one selected from the group consisting of an organic amine compound and an alcohol.

13. The etching method according to claim 1, wherein the film containing Si and O but not N is selectively etched without the use of a plasma state.

14. The etching method according to claim 1, wherein (I) the etching gas composition containing HF gas and (II) the surface treatment gas composition containing a surface treatment material are simultaneously contacted with the substrate.

15. The etching method according to claim 1, comprising: (II) a surface treatment step of contacting the substrate with a surface treatment gas composition containing a surface treatment material; and (I) an etching step of contacting the substrate with an etching gas composition containing HF gas after the surface treatment step.

16. The etching method according to claim 1, wherein the substrate temperature during etching is 20 to 300° C.

17. The etching method according to claim 1, wherein the pressure during etching is 1 Pa to 10 kPa.

18. The etching method according to claim 1, wherein the pressure during etching is 1 Pa or more and less than 1 kPa.

19. The etching method according to claim 1, wherein the film containing Si and O but no N is a silicon oxide (SiO) film.

20. The etching method according to claim 1, wherein the film containing Si and N is a silicon nitride (SiN) film.

21. The etching method according to claim 1, wherein, on the substrate, the film containing Si and O but not N is a silicon oxide (SiO) film, the film containing Si and N is a silicon nitride (SiN) film, the silicon nitride film is adjacent to the silicon oxide film, and the silicon oxide film and the silicon nitride film are exposed.

22. A method for manufacturing a semiconductor device, comprising a step of applying the etching method according to any one of claims 1 to 21 to a substrate having a film containing at least Si and O but not containing N and a film containing at least Si and N, to selectively etch the film containing Si and O but not containing N.

23. A method for manufacturing a semiconductor device, comprising the step of selectively etching a silicon oxide film by applying the etching method according to any one of claims 1 to 21 to a substrate having a silicon nitride film and a silicon oxide film.

24. An etching apparatus comprising: a mounting table for mounting a substrate; (I) an HF gas supply unit for supplying HF gas to the substrate; and (II) a surface treatment gas supply unit for supplying a surface treatment gas composition containing a surface treatment material to the substrate.

25. A surface treatment gas composition comprising a surface treatment material.

26. A surface treatment material-containing etching gas composition comprising HF gas and a surface treatment material.

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