Etching method, method for producing semiconductor device, etching apparatus and etching gas

Abstract

The purpose of the present disclosure is to provide a technology which is capable of etching a film that contains at least Si and N in a substrate that comprises a film that contains at least Si and O and the film that contains at least Si and N, while suppressing the etching of the film that contains at least Si and O. The present disclosure provides an etching method for etching a film that contains Si and N by bringing (I) an HF gas and (II) at least one compound that is selected from the group consisting of a sulfonyl compound, a carbonyl compound, a sulfonyl isocyanate compound and an isocyanate compound into contact with a substrate which comprises a film that contains at least Si and O and a film that contains at least Si and N.

Description

Etching method, semiconductor device manufacturing method, etching apparatus, and etching gas

[0001] The present disclosure relates to an etching method using HF gas and at least one compound selected from the group consisting of sulfonyl compounds, carbonyl compounds, sulfonyl isocyanate compounds, and isocyanate compounds, a semiconductor device manufacturing method, an etching apparatus, and an etching gas.

[0002] In the manufacture of semiconductor devices, silicon nitride (SiN) is grown on a single crystal silicon substrate to form silicon oxide (SiO ２ ) and a step of selectively etching the SiN from adjacent structures.

[0003] As an etching method for SiN, wet etching using hot phosphoric acid or CF ４ Dry etching using plasma generated from compound gases such as halocarbons is known.

[0004] For example, Patent Document 1 discloses SiO ２ , for selective plasma etching of SiN in the presence of metal silicide or silicon, ｘ F ４－ｘ (x represents 2 or 3) and an etching gas containing oxygen gas or the like. ２ It is described that the SiN film is selectively etched from the openings in the film, and the underlying p-Si film is used as an etching stop layer.

[0005] However, wet etching using hot phosphoric acid and dry etching using plasma remove not only SiN but also SiO ２ The SiO of SiN is also etched. ２ There was a concern that it would be difficult to increase the selectivity to

[0006] Therefore, Patent Document 2 discloses a method for producing SiO by passing HF gas in a plasma-free heated atmosphere. ２However, the method described in Patent Document 2 has a drawback that when the SiN film is etched with HF gas, HF and a reaction product, NH ３ By this, SiO ２ The film may also be etched, and the SiN / SiO ２ In some cases, it was not possible to increase the selectivity.

[0007] Therefore, Patent Document 3 discloses a method for forming a SiN film using a mixed gas of HF and a fluorine-containing carboxylic acid. ２ The fluorine-containing carboxylic acid is a by-product of etching a SiN film with HF, and the NH ３ By trapping SiO ２ It is described that the compound has the property of not etching the film and not inhibiting etching of SiN by HF.

[0008] Japanese Patent Laid-Open No. 8-59215 Japanese Patent Laid-Open No. 2008-187105 Japanese Patent Laid-Open No. 2019-91890

[0009] An object of the present disclosure is to provide a technique that, in a substrate having a film containing at least Si and O and a film containing at least Si and N, can etch the film containing at least Si and N while suppressing etching of the film containing at least Si and O.

[0010] As a result of extensive research, the present inventors have found that a sulfonyl compound, a carbonyl compound, a sulfonyl isocyanate compound, or an isocyanate compound can effectively remove Si—NH on the surface of the SiN film. ２ By bonding to NH, which is originally a by-product of the reaction between HF and SiN, ３ The present inventors have found that the above problems can be solved by etching the SiN film without generating fluorine and by combining fluorine with HF, and have completed the present disclosure.

[0011] The method described in Patent Document 3 involves the reaction of a fluorine-containing carboxylic acid with a by-product, NH ３ By forming a salt with ３ and trapping SiO ２On the other hand, the sulfonyl compounds, carbonyl compounds, sulfonyl isocyanate compounds, and isocyanate compounds of the present disclosure have a proton (H ＋ ) on the surface of the SiN film. ２ By directly bonding to NH ３ Therefore, the generation of SiO ２ It is presumed that the etching suppression effect of the film has been further improved.

[0012] That is, the present disclosure provides an etching method, a semiconductor device manufacturing method, and an etching apparatus as set forth in the following [1] to

[18] . [1] An etching method for etching a film containing Si and N by contacting a substrate having a film containing at least Si and O and a film containing at least Si and N with (I) HF gas and (II) at least one compound selected from the group consisting of a sulfonyl compound represented by the following general formula [1], a carbonyl compound represented by the following general formula [2], a sulfonyl isocyanate compound represented by the following general formula [3], and an isocyanate compound represented by the following general formula [4]. R １ -S(=O) ２ -X [1] (In general formula [1], R １ is a linear or branched alkyl group having 1 to 6 carbon atoms, some or all of whose hydrogen atoms may be substituted with fluorine atoms, or a halogen atom. X is a halogen atom. ２ -C(=O)-R ３ [2] (In general formula [2], R ２ and R ３ are each independently a linear or branched alkyl group having 1 to 6 carbon atoms, some or all of whose hydrogen atoms may be substituted with fluorine atoms, a hydrogen atom, a halogen atom, or an isocyanate group. ４ -S(=O) ２ N=C=O [3] (In general formula [3], R ４ R is a linear or branched alkyl group having 1 to 6 carbon atoms, some or all of whose hydrogen atoms may be substituted with fluorine atoms, or a halogen atom. ５-N=C=O [4] (In general formula [4], R ５ is a straight-chain or branched-chain alkyl group having 1 to 10 carbon atoms, some or all of whose hydrogen atoms may be substituted with fluorine atoms.) [2] The etching method according to [1] above, in which the film containing Si and N is etched without a plasma state. [3] The etching method according to [1] or [2] above, characterized in that the film containing Si and N is selectively etched. [4] The etching method according to [1] or [2] above, in which the etching is selectively performed on the film containing Si and N, and the etching of the film containing Si and O is performed at a rate of 1.0 nm / min or less. [5] R in the general formula [1] above １ [6] The etching method according to any one of the above [1] to [4], wherein X is a fluoroalkyl group or a fluorine atom, and X is a fluorine atom. [7] The sulfonyl compound represented by the above general formula [1] is trifluoromethanesulfonyl fluoride (CF ３ S (= O) ２ F), or sulfuryl fluoride (SO ２ F ２ [7] The etching method according to any one of the above [1] to [5], wherein the carbonyl compound represented by the general formula [2] is hexafluoroacetone (CF ３ C(=O)CF ３ ), trifluoroacetaldehyde (CF ３ [8] The etching method according to any one of the above items [1] to [6], wherein the isocyanate compound represented by the general formula [3] is fluorosulfonyl isocyanate (FS(=O) ２[9] The etching method according to any one of [1] to [8] above, wherein the etching is carried out by placing the substrate in a chamber, and includes a step of subjecting the chamber to a reduced pressure.

[10] The etching method according to any one of [1] to [9] above, wherein (I) HF gas and the compound (II) are simultaneously brought into contact with the substrate.

[11] The etching method according to any one of [1] to [9] above, comprising (I) a first etching step of bringing HF gas into contact with the substrate, and a second etching step of bringing the compound (II) into contact with the substrate.

[12] The etching method according to

[11] above, wherein etching is carried out by repeating the first etching step and the second etching step.

[13] The etching method according to

[11] or

[12] above, wherein the first etching step is carried out after the second etching step is carried out.

[14] The film containing Si and O is silicon oxide (SiO ２

[15] The etching method according to any one of [1] to

[14] above, wherein the film containing Si and N is a silicon nitride (SiN) film.

[16] In the substrate, the film containing Si and O is a silicon oxide (SiO ２

[16] An etching method according to any one of [1] to

[13] above, wherein the film containing Si and N is a silicon nitride (SiN) film, the silicon nitride film is adjacent to a silicon oxide film, and the silicon oxide film and the silicon nitride film are exposed.

[17] A method for manufacturing a semiconductor device, comprising the step of selectively etching a silicon nitride film by applying the etching method according to any one of [1] to

[16] above to a substrate having a silicon nitride film and a silicon oxide film.

[18] An etching apparatus comprising: a mounting table for mounting a substrate thereon; (I) an HF gas supply unit for supplying HF gas; and (II) a gas compound (II) supply unit for supplying a gas of at least one compound selected from the group consisting of a sulfonyl compound represented by the following general formula [1], a carbonyl compound represented by the following general formula [2], a sulfonyl isocyanate compound represented by the following general formula [3], and an isocyanate compound represented by the following general formula [4].１ -S(=O) ２ -X [1] (In general formula [1], R １ is a linear or branched alkyl group having 1 to 6 carbon atoms, some or all of whose hydrogen atoms may be substituted with fluorine atoms, or a halogen atom. X is a halogen atom. ２ -C(=O)-R ３ [2] (In general formula [2], R ２ and R ３ are each independently a linear or branched alkyl group having 1 to 6 carbon atoms, some or all of whose hydrogen atoms may be substituted with fluorine atoms, a hydrogen atom, a halogen atom, or an isocyanate group. ４ -S(=O) ２ N=C=O [3] (In general formula [3], R ４ R is a linear or branched alkyl group having 1 to 6 carbon atoms, some or all of whose hydrogen atoms may be substituted with fluorine atoms, or a halogen atom. ５ -N=C=O [4] (In general formula [4], R ５ is a straight-chain or branched-chain alkyl group having 1 to 10 carbon atoms in which some or all of the hydrogen atoms may be substituted with fluorine atoms.)

[19] An etching gas containing (I) HF gas, and (II) at least one compound selected from the group consisting of a sulfonyl compound represented by the following general formula [1], a carbonyl compound represented by the following general formula [2], a sulfonyl isocyanate compound represented by the following general formula [3], and an isocyanate compound represented by the following general formula [4]. R １ -S(=O) ２ -X [1] (In general formula [1], R １ is a linear or branched alkyl group having 1 to 6 carbon atoms, some or all of whose hydrogen atoms may be substituted with fluorine atoms, or a halogen atom. X is a halogen atom. ２ -C(=O)-R ３ [2] (In general formula [2], R ２ and R ３are each independently a linear or branched alkyl group having 1 to 6 carbon atoms, some or all of whose hydrogen atoms may be substituted with fluorine atoms, a hydrogen atom, a halogen atom, or an isocyanate group. ４ -S(=O) ２ N=C=O [3] (In general formula [3], R ４ R is a linear or branched alkyl group having 1 to 6 carbon atoms, some or all of whose hydrogen atoms may be substituted with fluorine atoms, or a halogen atom. ５ -N=C=O [4] (In general formula [4], R ５ is a linear or branched alkyl group having 1 to 10 carbon atoms in which some or all of the hydrogen atoms may be substituted with fluorine atoms.

[0013] According to the present disclosure, in a substrate having a film containing at least Si and O and a film containing at least Si and N, by using an etching gas containing HF gas and at least one compound selected from the group consisting of a sulfonyl compound represented by general formula [1], a carbonyl compound represented by general formula [2], a sulfonyl isocyanate compound represented by general formula [3], and an isocyanate compound represented by general formula [4], it is possible to achieve the effect of etching the film containing at least Si and N while suppressing etching of the film containing at least Si and O.

[0014] FIG. 1 is a schematic diagram illustrating an etching apparatus according to an embodiment of the present disclosure.

[0015] The present disclosure will be described in detail below. The present disclosure is not limited to the following embodiments, and can be appropriately implemented based on the common knowledge of those skilled in the art within the scope of the present disclosure.

[0016] <Etching Method> The etching method of the present disclosure is characterized in that a substrate having a film containing at least Si and O and a film containing at least Si and N is contacted with (I) HF gas and (II) at least one compound selected from the group consisting of a sulfonyl compound represented by the following general formula [1], a carbonyl compound represented by the following general formula [2], a sulfonyl isocyanate compound represented by the following general formula [3], and an isocyanate compound represented by the following general formula [4] (hereinafter also referred to as "compound (II)"), thereby etching the film containing Si and N. １ -S(=O) ２ -X [1] (In general formula [1], R １ is a linear or branched alkyl group having 1 to 6 carbon atoms, some or all of whose hydrogen atoms may be substituted with fluorine atoms, or a halogen atom. X is a halogen atom. ２ -C(=O)-R ３ [2] (In general formula [2], R ２ and R ３ are each independently a linear or branched alkyl group having 1 to 6 carbon atoms, some or all of whose hydrogen atoms may be substituted with fluorine atoms, a hydrogen atom, a halogen atom, or an isocyanate group. ４ -S(=O) ２ N=C=O [3] (In general formula [3], R ４ R is a linear or branched alkyl group having 1 to 6 carbon atoms, some or all of whose hydrogen atoms may be substituted with fluorine atoms, or a halogen atom. ５ -N=C=O [4] (In general formula [4], R ５ is a linear or branched alkyl group having 1 to 10 carbon atoms in which some or all of the hydrogen atoms may be substituted with fluorine atoms.

[0017] As a film containing at least Si and O, silicon oxide (SiO ２ An example of a film containing at least Si and N is a silicon nitride (SiN) film.

[0018] R in general formula [1] １Examples of the linear or branched alkyl group having 1 to 6 carbon atoms, some or all of whose hydrogen atoms may be substituted with fluorine atoms, include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a t-butyl group, an n-pentyl group, and an n-hexyl group. １ Examples of the halogen atom in R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. １ is preferably a fluoroalkyl group or a fluorine atom. １ is more preferably a trifluoromethyl group or a fluorine atom. As the halogen atom represented by X in the general formula [1], R １ X is preferably a fluorine atom.

[0019] Specific examples of the sulfonyl compound represented by the general formula [1] include trifluoromethanesulfonyl fluoride (CF ３ S (= O) ２ F), sulfuryl fluoride (SO ２ F ２ ), trifluoromethanesulfonyl chloride (CF ３ S (= O) ２ Cl), sulfuryl chloride (SO ２ Cl ２ The sulfonyl compound is trifluoromethanesulfonyl fluoride (CF ３ S (= O) ２ F), or sulfuryl fluoride (SO ２ F ２ ) is preferred.

[0020] R in general formula [2] ２ and R ３ A linear or branched alkyl group having 1 to 6 carbon atoms, in which some or all of the hydrogen atoms may be substituted with fluorine atoms, and a halogen atom are represented by R １ Examples of the examples are shown in R. ２ and R ３ R is preferably an alkyl group, a trifluoroalkyl group, or a hydrogen atom, and more preferably a methyl group, a trifluoromethyl group, or a hydrogen atom. ２ and R ３Carbonyl compounds in which one of the above is a halogen atom and the other is an isocyanate group are also preferred.

[0021] Specific examples of the carbonyl compound represented by the general formula [2] include hexafluoroacetone (CF ３ C(=O)CF ３ ), trifluoroacetaldehyde (CF ３ C(=O)H), acetone (CH ３ C(=O)CH ３ ), acetaldehyde (CH ３ Examples of the carbonyl compound include hexafluoroacetone (CF ３ C(=O)CF ３ ), trifluoroacetaldehyde (CF ３ C(=O)H), fluorocarbonyl isocyanate (FC(=O)N=C=O), and hexafluoroacetone (CF ３ C(=O)CF ３ ), trifluoroacetaldehyde (CF ３ Acetaldehyde and trifluoroacetaldehyde may exist in the form of stable equivalents such as self-polymers, hydrates, hemiacetals, acetals, and compounds combining these structural features. Therefore, in the present invention, these stable equivalents are also considered to be included in the carbonyl compound represented by the general formula [2].

[0022] R in general formula [3] ４ A linear or branched alkyl group having 1 to 6 carbon atoms, in which some or all of the hydrogen atoms may be substituted with fluorine atoms, and a halogen atom are represented by R １ Examples of the examples are shown in R. ４ A halogen atom is preferable, and a fluorine atom is more preferable. Specific examples of the sulfonyl isocyanate compound represented by the general formula [3] include fluorosulfonyl isocyanate (FS(═O) ２N=C=O), chlorosulfonyl isocyanate (ClS(=O) ２ The sulfonyl isocyanate compound may be fluorosulfonyl isocyanate (FS(=O) ２ It is preferred that the alkyl group is N=C=O.

[0023] R in general formula [4] ５ A linear or branched alkyl group having 1 to 10 carbon atoms, in which some or all of the hydrogen atoms may be substituted with fluorine atoms, is represented by R １ As well as an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, etc. Specific examples of the isocyanate compound represented by the general formula [4] include methyl isocyanate, ethyl isocyanate, n-propyl isocyanate, isopropyl isocyanate, n-butyl isocyanate, tert-butyl isocyanate, etc. From the viewpoint of reactivity with Si and a film containing N, methyl isocyanate, ethyl isocyanate, and n-propyl isocyanate are preferred as the isocyanate compound.

[0024] The process temperature for contacting the film formed on the substrate with (I) HF gas is preferably 20° C. or higher and 200° C. or lower, more preferably 30° C. or higher and 150° C. or lower, and even more preferably 40° C. or higher and 130° C. or lower. The process temperature for contacting the film formed on the substrate with the compound (II), and the process temperature for simultaneously contacting the film formed on the substrate with (I) HF gas and the compound (II), are also preferably within the above-mentioned range. When the process temperature is within the above-mentioned temperature range, the reactivity with the film containing Si and N is good, productivity is good, and damage to the substrate is small.

[0025] The etching method of the present disclosure preferably etches the film containing Si and N 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.

[0026] The etching method of the present disclosure is suitable for selectively etching the film containing Si and N. In the etching method of the present disclosure, etching is preferably performed selectively on the film containing Si and N, and etching on the film containing Si and O is preferably performed at a rate of 1.0 nm / min or less. More preferably, the rate is 0.5 nm / min or less. The etching rate is a value calculated based on the contact time of HF gas. In this specification, "selectively etching a film containing Si and N" means that the ratio of the etching rates of the film containing Si and N to the film containing Si and O (film containing Si and N / film containing Si and O) is 5 or more. The etching rate ratio is preferably 10 or more, more preferably 15 or more, and particularly preferably 30 or more.

[0027] 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 and the film containing Si and O and the film containing Si and N formed on the surface of the substrate.

[0028] 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.

[0029] 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. The etching method of the present disclosure more preferably includes a step of subjecting the chamber to a reduced pressure state after contacting the HF gas (I) and the compound (II) with a substrate having a film containing at least Si and O and a film containing at least Si and N in the chamber. 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, meaning approximately 0.133 kPa or less.

[0030] 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 the HF gas (I) with the compound (II). 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 the substrate with the HF gas (I) and the compound (II).

[0031] [First Etching Method] First, as an etching method of the present disclosure, a first etching method in which the above-mentioned (I) HF gas and the above-mentioned (II) compound are simultaneously brought into contact with the above-mentioned substrate will be described. Hereinafter, the etching gas used in the first etching method will be referred to as etching gas A, and etching gas A contains at least the above-mentioned (I) HF gas and the above-mentioned (II) compound.

[0032] In the following description, a film containing at least Si and O and a film containing at least Si and N are also referred to as a film to be etched. When the film to be etched in a heated state is simultaneously brought into contact with (I) HF gas and (II) compound, the compound (II) and Si—NH on the surface of the film containing Si and N (particularly a SiN film) are etched. ２ and are directly bonded to form NH ３ It is assumed that the production of NH ３ It is believed that etching of the film containing Si and O by the etching gas is suppressed, and the film containing Si and N can be selectively etched.

[0033] The compound (II) includes the same compounds as those described above.

[0034] The volume ratio of (I) HF gas to (II) compound is preferably HF gas:(II) compound = 10:0.01 or more and 10 or less, more preferably 10:0.01 or more and 6 or less. If the proportion of HF gas is too small, the etching rate tends to decrease, and if it is too high, it becomes too expensive. Also, if there is too much (II) compound, etching does not proceed easily. Since even a small amount of (II) compound is effective, the amount of (II) compound may be 1 ppm by volume or more, assuming that the total of HF gas, (II) compound, and the additive gas described below is 100% by volume.

[0035] The etching gas A may consist of only (I) HF gas and (II) compound, but may also contain O ２ , NO, N ２ O, CO, CO ２ , H ２ O ２ and alcohols, and ２ The inert gas may further contain at least one inert gas selected from the group consisting of Ar, He, Ne, and Kr. As the alcohol, methanol, ethanol, propanol, isopropyl alcohol, etc. may be used.

[0036] When an additive gas is used, the total content of the additive gas can be 10% by volume or more and 90% by volume or less, where the total of (I) HF gas, (II) compound, the additive gas, and the inert gas is 100% by volume.

[0037] When the etching gas A contains an inert gas, the content of the inert gas contained in the etching gas A is preferably 1% by volume or more and 90% by volume or less, more preferably 10% by volume or more and 80% by volume or less, and even more preferably 30% by volume or more and 50% by volume or less, where the total of (I) HF gas, (II) compound, the additive gas, and the inert gas is 100% by volume.

[0038] The amount of moisture in the etching gas A is preferably less than 1 mass %. If the amount of moisture is large, the etching gas A may produce H ２ O is produced, and HF+H ２ O to form a film containing Si and O (SiO ２ This is because etching of the film may occur.

[0039] The first etching method preferably includes a step of simultaneously contacting the substrate with the HF gas (I) and the compound (II) in a chamber, and a step of reducing the pressure in the chamber, and etching is performed by repeating these steps. Instead of reducing the pressure in 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 in the chamber. In one embodiment, the first etching method preferably includes a step of simultaneously contacting the substrate with the HF gas (I) and the compound (II) in a chamber, followed by a step of reducing the pressure in the chamber and / or a step of replacing the chamber with an inert gas.

[0040] [Second Etching Method] Next, as an etching method of the present disclosure, a second etching method will be described, which includes a first etching step of contacting the substrate with the HF gas described above (I) and a second etching step of contacting the substrate with the compound described above (II). Hereinafter, the etching gas used in the first etching step of the second etching method will be referred to as etching gas B, and the etching gas used in the second etching step will be referred to as etching gas C. The etching gas B contains at least the HF gas described above (I), and the etching gas C contains at least the compound described above (II).

[0041] In the second etching step, when the etching gas C containing the compound (II) is brought into contact with the film to be etched in a heated state, protons (H ＋ ), the compound (II) reacts with Si—NH on the surface of a film containing Si and N (particularly a SiN film). ２ Then, in the first etching step, (I) etching gas B containing HF gas is brought into contact with the SiO2 film, and NH ３ It is believed that the film containing Si and N can be selectively etched without generating ions. In the second 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 a constant thickness in one etching cycle, by specifying the number of cycles, it is possible to precisely etch a layer of a desired thickness.

[0042] As the compound (II), the same compounds as those described above can be used.

[0043] The etching gas B may consist of only (I) HF gas, and the etching gas C may consist of only (II) compound. However, the etching gas B and the etching gas C each contain O ２ , NO, N ２ O, CO, CO ２ , H ２ O ２ The etching gas B and the etching gas C may further contain at least one additive gas selected from the group consisting of N２ The inert gas may further contain at least one inert gas selected from the group consisting of Ar, He, Ne, and Kr. As the alcohol, methanol, ethanol, propanol, isopropyl alcohol, etc. may be used.

[0044] When etching gas B contains an additive gas, the total content of the additive gas contained in etching gas B can be 10% by volume or more and 90% by volume or less, where the total of (I) HF gas, the additive gas, and the inert gas is 100% by volume. When etching gas C contains an additive gas, the total content of the additive gas contained in etching gas C can be 10% by volume or more and 90% by volume or less, where the total of (II) compound, the additive gas, and the inert gas is 100% by volume.

[0045] When etching gas B contains an inert gas, the content of the inert gas contained in etching gas B is preferably 1% by volume or more and 90% by volume or less, more preferably 10% by volume or more and 80% by volume or less, and even more preferably 30% by volume or more and 50% by volume or less, based on 100% by volume of the total of (I) HF gas, the additive gas, and the inert gas. When etching gas C contains an inert gas, the content of the inert gas contained in etching gas C is preferably 1% by volume or more and 90% by volume or less, more preferably 10% by volume or more and 80% by volume or less, and even more preferably 30% by volume or more and 50% by volume or less, based on 100% by volume of the total of (II) compound, the additive gas, and the inert gas.

[0046] The moisture content in the etching gas B and the moisture content in the etching gas C are preferably less than 1 mass %. If the moisture content is high, the etching gas B may produce H ２ O is produced, and HF+H ２ O to form a film containing Si and O (SiO ２ This is because etching of the film may occur.

[0047] The second etching method preferably includes a first etching step and a second etching step performed in a chamber, and further includes a step of reducing the pressure inside the chamber. It is preferable to perform 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 includes a step of reducing the pressure inside the chamber and / or a step of replacing the atmosphere inside the chamber with an inert gas after performing the second etching step, and then a step of reducing the pressure inside the chamber and / or a step of replacing the atmosphere inside the chamber with an inert gas after performing the first etching step.

[0048] The present disclosure also provides an etching method for etching the film containing Si and N by contacting a substrate having a polycrystalline silicon film and a film containing at least Si and N with (I) HF gas and (II) at least one compound selected from the group consisting of a sulfonyl compound represented by the general formula [1] above, a carbonyl compound represented by the general formula [2] above, a sulfonyl isocyanate compound represented by the general formula [3] above, and an isocyanate compound represented by the general formula [4] above.

[0049] In addition to the polycrystalline silicon film and the film containing at least Si and N, a film containing at least Si and O, a film containing a metal nitride, a silicon film, a metal wiring film, etc. may be formed on the surface of the substrate.

[0050] The compound (II) to be brought into contact with the substrate and the etching conditions can be the same as those of the etching method performed on the substrate having the above-mentioned film containing at least Si and O and the above-mentioned film containing at least Si and N.

[0051] [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 includes a mounting table on which a substrate is placed, (I) an HF gas supply unit that supplies the above-mentioned HF gas, and (II) a gas compound (II) supply unit that supplies a gas of at least one compound selected from the group consisting of a sulfonyl compound represented by general formula [1], a carbonyl compound represented by general formula [2], a sulfonyl isocyanate compound represented by general formula [3], and an isocyanate compound represented by general formula [4] (hereinafter also referred to as gas compound (II)). The etching apparatus of the present disclosure may further include an inert gas supply unit that supplies an inert gas into the chamber.

[0052] Fig. 1 is a schematic diagram showing an etching apparatus according to an embodiment of the present disclosure. The etching apparatus 100 shown in Fig. 1 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 gas compound (II) supply unit 150 supplying a gas compound (II), an inert gas supply unit 130 supplying an inert gas, and a heating unit 111 for heating the chamber 110. Note that the etching apparatus 100 does not necessarily have to include the inert gas supply unit 130.

[0053] 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.

[0054] 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.

[0055] 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 .

[0056] The gas compound (II) supply unit 150 adjusts the supply amount using valves 153 and 154 and a flow rate adjusting means 152 , and supplies the gas compound (II) from pipes 151 and 155 to the pipe 121 .

[0057] 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 .

[0058] 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.

[0059] A gas exhaust means for exhausting post-reaction gas is provided on one side of the chamber 110. A vacuum pump 127 of the gas exhaust means exhausts the post-reaction gas from the chamber 110 via a pipe 122. The post-reaction gas can be recovered by providing a liquid nitrogen trap (not shown) between the pipe 122 and the vacuum pump 127. Valves 125 and 126 are provided on the pipes 121 and 122 to adjust the pressure. In addition, in FIG. 1, 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.

[0060] A specific etching method will be described using the etching apparatus 100 as an example. [First Etching Method Using the Above Etching Apparatus] In the first etching method of the present disclosure, an etching gas A containing (I) HF gas and (II) a compound is brought into contact with a film to be etched.

[0061] In the first etching method, first, a substrate 113 having a film to be etched, which includes a film containing at least Si and O and a film containing at least Si and N, is placed in a 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 a vacuum pump 127, and then the substrate 113 is heated by a heating means 111. Once the substrate 113 reaches a predetermined temperature, HF gas and gas compound (II) are supplied to the pipe 121 at predetermined flow rates from an HF gas supply unit 140 and a gas compound (II) supply unit 150. Note that an inert gas may be supplied to the pipe 121 from an inert gas supply unit 130 at a predetermined flow rate.

[0062] HF gas and gas compound (II) are mixed at a predetermined composition and supplied to the chamber 110. While the mixed etching gas 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 A with the film to be etched for a predetermined time. This etching method enables plasmaless etching without a plasma state, and does not require excitation of the etching gas A with plasma or the like during etching. The flow rate of the etching gas A can be set appropriately based on the volume and pressure of the chamber, etc.

[0063] 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 of the present disclosure, a gas is brought into contact without a plasma state, and dry etching is performed without generating the above-mentioned gas plasma.

[0064] 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 N of the film to be etched can be selectively etched.

[0065] (Etching Conditions in First Etching Method) In the first etching method of the present disclosure, the temperature of the film to be etched when the etching gas A is brought into contact with the film to be etched may be a temperature at which the etching gas A reacts with the film containing Si and N (SiN film). In particular, the temperature of the film to be etched to be removed is preferably 20°C or higher and 200°C or lower, more preferably 30°C or higher and 150°C or lower, and even more preferably 40°C or higher and 130°C or lower.

[0066] Furthermore, when the etching gas A is brought into contact with the film to be etched, the pressure in the chamber in which the substrate on which the film to be etched is formed is placed is not particularly limited, but is usually in the pressure range of 0.01 kPa or more and 101.3 kPa or less.

[0067] In order to obtain a sufficient etching rate, the pressure in the chamber during the etching step is preferably 0.01 kPa or more and 101.3 kPa or less, more preferably 0.1 kPa or more and 50 kPa or less, and even more preferably 1 kPa or more and 20 kPa or less.

[0068] The processing 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 processing time of the etching step refers to the time from when the etching gas A is introduced into the chamber in which the substrate is placed until the etching gas A in the chamber is subsequently evacuated by a vacuum pump or the like to complete the etching process.

[0069] [Second Etching Method Using the Etching Apparatus] The second etching method of the present disclosure includes a first etching step of bringing an etching gas B containing HF gas into contact with a film to be etched, and a second etching step of bringing an etching gas C containing the compound (II) into contact with the film to be etched.

[0070] 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.

[0071] When the substrate 113 reaches a predetermined temperature, first, the gas compound (II) is supplied from the gas compound (II) supply unit 150 to the pipe 121 at a predetermined flow rate. Alternatively, the inert gas may be supplied from the inert gas supply unit 130 to the pipe 121 at a predetermined flow rate. While the gas compound (II) or the gas compound (II) and the inert gas are introduced into the chamber 110, the pressure inside the chamber 110 is controlled to a predetermined value. By introducing the gas compound (II) into the chamber 110 for a predetermined time, the gas compound (II) is adsorbed to the film to be etched. After evacuating the gas containing the gas compound (II), HF gas is supplied from the HF gas supply unit 140 to the pipe 121 at a predetermined flow rate. Alternatively, the inert gas may be supplied from the inert gas supply unit 130 to the pipe 121 at a predetermined flow rate. While HF gas or HF gas and the inert gas are introduced into the chamber 110, the pressure inside the chamber 110 is controlled to a predetermined value. By introducing HF gas into the chamber 110 for a predetermined time, the film containing Si and N of the above-mentioned film to be etched can be selectively etched.

[0072] In the second etching method of the present disclosure, a cycle consisting of a first etching step of introducing HF gas into the chamber 110 and a second etching step of introducing the gas compound (II) into the chamber 110 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 second etching step, a step of subjecting the chamber to a reduced pressure state is preferably performed, and then the first etching step is performed. Furthermore, it is preferable to subject the chamber to a reduced pressure state for each cycle.

[0073] In addition, the second etching method can also be performed without plasma, and does not require excitation of the etching gas with plasma, etc. The flow rates of the HF gas and the gas compound (II) can be appropriately set based on the volume and pressure of the chamber, etc.

[0074] In this way, in the second etching method of the present disclosure using the above etching apparatus, the gas can be brought into contact without a plasma state, and dry etching can be performed without generating the above-mentioned gas plasma.

[0075] 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 replaced with an inert gas to release the vacuum. By the second etching method using the above etching apparatus, a film containing Si and N in the film to be etched can be selectively etched.

[0076] (Etching Conditions in Second Etching Method) In the second etching method of the present disclosure, the temperature of the film to be etched during the etching step may be a temperature at which etching gas B reacts with a film containing Si and N (SiN film) and a temperature at which etching gas C reacts with a film containing Si and N (SiN film), and in particular, the temperature of the film to be etched to be removed is preferably 20° C. or higher and 200° C. or lower, more preferably 30° C. or higher and 150° C. or lower, and even more preferably 40° C. or higher and 130° C. It is desirable that the temperature of the film to be etched in the first etching step and the second etching step be the same.

[0077] The pressure in the chamber during the etching step is not particularly limited, but is usually in the range of 0.01 kPa to 101.3 kPa.

[0078] From the viewpoint of obtaining a sufficient etching rate, the pressure in the chamber in the first etching step and the second etching step is preferably 0.01 kPa or more and 101.3 kPa or less, more preferably 0.1 kPa or more and 50 kPa or less, and even more preferably 1 kPa or more and 20 kPa or less. The pressure in the chamber in the second etching step is desirably higher than the pressure in the chamber in the first etching step.

[0079] The treatment times in the first etching step and the second etching step are not particularly limited, but the treatment time for one cycle of the first etching step is preferably 60 minutes or less, and the treatment time for one cycle of the second etching step is preferably 60 minutes or less. Here, the treatment time of 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 process.

[0080] [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 silicon nitride film by applying the etching method to a substrate having a silicon nitride film and a silicon oxide film. By selectively etching a silicon nitride 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 the silicon nitride film by applying the etching method to a substrate having a silicon nitride film and a silicon oxide film. The step of reacting HF gas and compound (II) with the substrate having a silicon nitride film and a silicon oxide film to selectively etch the silicon nitride film without a plasma state 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.

[0081] [Etching Gas] The present disclosure also provides an etching gas comprising (I) HF gas and (II) at least one compound selected from the group consisting of a sulfonyl compound represented by the general formula [1] above, a carbonyl compound represented by the general formula [2] above, a sulfonyl isocyanate compound represented by the general formula [3] above, and an isocyanate compound represented by the general formula [4] above. The etching gas of the present disclosure may be in the same form as the etching gas A described above. That is, the etching gas of the present disclosure is a mixture containing at least the HF gas (I) above and the compound (II) above.

[0082] 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 with a film formed thereon and a silicon wafer with a polycrystalline silicon (p-Si) film formed thereon were 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 amount of etching and the amount of SiO ２ , and the selectivity of SiN to p-Si (SiN / SiO ２The selectivity, and SiN / p-Si selectivity) were determined.

[0083] Example 1 The etching apparatus 100 shown in FIG. 1 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 2 was introduced into the chamber. ２ After that, HF gas and CF gas were introduced into the chamber. ３ S (= O) ２ F (trifluoromethanesulfonyl fluoride) gas was passed through for 1 min. The gas flow rates at this time were HF gas = 200 sccm, CF ３ S (= O) ２ The F gas was 100 sccm, and the pressure in the chamber was 6.66 kPa. 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 The silicon wafer on which the film was formed and the silicon wafer on which the polycrystalline silicon (p-Si) film was formed were all placed in the same chamber and etched simultaneously.

[0084] [Example 2] HF gas and CF ３ S (= O) ２ Instead of F gas, HF gas and CF ３ C(=O)CF ３ The test was carried out under the same conditions as in Example 1, except that the (hexafluoroacetone) gas was passed through for 15 minutes. The results are shown in Table 1.

[0085] [Example 3] HF gas and CF ３ S (= O) ２ Instead of F gas, HF gas and FS(=O) ２ The test was carried out under the same conditions as in Example 1, except that N═C═O (fluorosulfonyl isocyanate) gas was passed through for 15 minutes. The results are shown in Table 1.

[0086] [Example 4] HF gas and CF ３ S (= O) ２Instead of F gas, HF gas and S(=O) ２ F ２ The test was carried out under the same conditions as in Example 1, except that the (sulfuryl fluoride) gas was passed through for 15 minutes. The results are shown in Table 1.

[0087] Comparative Example 1 HF gas and CF ３ S (= O) ２ Instead of F gas, HF gas and N ２ The test was carried out under the same conditions as in Example 1, except that the gas was passed for 10 minutes. The results are shown in Table 1.

[0088] Example 5 First, a substrate to be processed was placed on a mounting table in a chamber, and the chamber was sufficiently evacuated, and then the temperature of the mounting table was set to 120° C. Next, N 2 was introduced into the chamber. ２ (A) After that, CF4 was introduced into the chamber. ３ S (= O) ２ After passing F gas, vacuum the area thoroughly and ２ The gas flow rate was CF ３ S (= O) ２ F gas = 100 sccm, pressure 6.66 kPa, CF ３ S (= O) ２ The F gas flow time was 2 min. (B) Next, HF gas was introduced into the chamber using N ２ After diluting with gas, the gas is circulated and then vacuumed thoroughly. ２ The gas flow rate was HF gas = 200 sccm, N ２ Gas = 100 sccm, pressure 6.66 kPa, HF gas / N ２ The gas flow time was 1 min. Here, cycle etching was performed by repeating (A) and (B) 10 times. Finally, the substrate to be treated was removed from the chamber. The results are shown in Table 2. The etching rate was calculated based on the ratio of HF gas to N ２ The value was calculated based on the gas flow time.

[0089] [Example 6] The pressure in the chamber was set to 5.33 kPa, and HF gas and CF ３ S (= O) ２The test was carried out under the same conditions as in Example 1, except that the F gas was passed for 3 minutes. The results are shown in Table 3.

[0090] [Example 7] The temperature of the mounting table was set to 50°C, and HF gas and CF ３ S (= O) ２ The test was carried out under the same conditions as in Example 1, except that the F gas was passed for 3 minutes. The results are shown in Table 3.

[0091] [Example 8] The pressure in the chamber was set to 4.00 kPa, and HF gas and CF ３ S (= O) ２ The test was carried out under the same conditions as in Example 7, except that F gas was passed through. The results are shown in Table 3.

[0092] [Example 9] The pressure in the chamber was set to 2.00 kPa, and HF gas and CF ３ S (= O) ２ The test was carried out under the same conditions as in Example 7, except that F gas was passed through. The results are shown in Table 3.

[0093] [Example 10] The temperature of the mounting table was set to 30°C, and HF gas and CF ３ S (= O) ２ The test was carried out under the same conditions as in Example 1, except that the F gas was passed for 3 minutes. The results are shown in Table 3.

[0094] [Example 11] The pressure in the chamber was set to 4.00 kPa, and HF gas and CF ３ S (= O) ２ The test was carried out under the same conditions as in Example 10, except that F gas was passed through. The results are shown in Table 3.

[0095] [Example 12] The pressure in the chamber was set to 2.00 kPa, and HF gas and CF ３ S (= O) ２ The test was carried out under the same conditions as in Example 10, except that F gas was passed through. The results are shown in Table 3.

[0096] [Comparative Example 2] The pressure in the chamber was set to 13.33 kPa, and HF gas and CF ３ S (= O) ２ Instead of F gas, HF gas and N ２The test was carried out under the same conditions as in Example 6, except that the gas was passed for 30 minutes. The results are shown in Table 3.

[0097] Comparative Example 3: The pressure in the chamber was set to 4.00 kPa, and HF gas and CF ３ S (= O) ２ Instead of F gas, HF gas and N ２ The test was carried out under the same conditions as in Example 6, except that the gas was passed for 30 minutes. The results are shown in Table 3.

[0098]

[0099]

[0100]

[0101] Table 1 shows the flow conditions of each gas in Examples 1 to 4 and Comparative Example 1, the etching rate of the substrate to be processed, and the SiN / SiO ２ Table 2 shows the results of the gas flow conditions in Example 5, the etching rate of the substrate to be processed, the SiN / SiO ２ Table 3 shows the results of the gas flow conditions, etching rate of the substrate to be processed, SiN / SiO selectivity, and SiN / p-Si selectivity for Examples 6 to 12 and Comparative Examples 2 and 3. ２ The results of the selectivity and SiN / p-Si selectivity are shown below. ２ The etching rate of the film was 0.0 to 0.2 nm in Examples 1 to 12, whereas it was ≧1.0 nm in Comparative Examples 1 to 3. In Examples 1 to 12, the SiO ２ The etching of the film was suppressed. SiN / SiO ２ The selectivity was ∞ in Examples 1, 3, 5, 8-9, and 11-12, 36 in Example 2, 18 in Example 4, 47 in Example 6, 73 in Example 7, and 32 in Example 10. The SiN / p-Si selectivity was ∞ in Examples 1 to 12. In Comparative Example 1, the SiN / p-Si selectivity was ∞, and the SiN / SiO ２ Although the selectivity is 1.9, SiO ２ As a result, the surface was scraped. From the results of Examples 1 to 12, it was found that HF ​​gas and CF ３ S (= O) ２By passing the compound (II) such as F gas through the catalyst, SiO ２ It has become clear that it is possible to etch SiN while suppressing etching of p-Si.

[0102] 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 Pipes 132 Flow rate adjustment means 133, 134 Valves 140 HF gas supply unit 141, 145 Pipes 142 Flow rate adjustment means 143, 144 Valves 150 Gas compound (II) supply unit 151, 155 Pipes 152 Flow rate adjustment means 153, 154 Valves

Claims

1. An etching method for etching a film containing Si and N on a substrate having a film containing at least Si and O and a film containing at least Si and N, by contacting (I) HF gas and (II) at least one compound selected from the group consisting of a sulfonyl compound represented by the following general formula [1], a carbonyl compound represented by the following general formula [2], a sulfonyl isocyanate compound represented by the following general formula [3], and an isocyanate compound represented by the following general formula [4]. R １ -S(=O) ２ -X [1] (In general formula [1], R １ X is a linear or branched alkyl group having 1 to 6 carbon atoms, or a halogen atom, in which some or all of the hydrogen atoms may be replaced by fluorine atoms. R ２ -C(=O)-R ３ [2] (In general formula [2], R ２ and R ３ Each of these is independently a linear or branched alkyl group, hydrogen atom, halogen atom, or isocyanate group having 1 to 6 carbon atoms, in which some or all of the hydrogen atoms may be substituted with fluorine atoms. R ４ -S(=O) ２ N=C=O [3] (In general formula [3], R ４ This refers to a linear or branched alkyl group or halogen atom having 1 to 6 carbon atoms, in which some or all of the hydrogen atoms may be replaced by fluorine atoms. R ５ -N=C=O [4] (In general formula [4], R ５ This refers to a linear or branched alkyl group having 1 to 10 carbon atoms, in which some or all of the hydrogen atoms may be substituted with fluorine atoms.

2. The etching method according to claim 1, wherein the film containing Si and N is etched without the creation of a plasma state.

3. The etching method according to claim 1, characterized by selectively etching the film containing Si and N.

4. The etching method according to claim 1, wherein the etching is performed selectively on the film containing Si and N, and the etching of the film containing Si and O is performed at a rate of 1.0 nm / min or less.

5. R in the general formula [1] １ The etching method according to claim 1, wherein is a fluoroalkyl group or a fluorine atom, and X is a fluorine atom.

6. The sulfonyl compound represented by the general formula [1] is trifluoromethanesulfonyl fluoride (CF ３ S (=O) ２ F), or sulfurylfluoride (SO ２ F ２ The etching method according to claim 1, wherein the etching method is as follows:

7. The carbonyl compound represented by the general formula [2] is hexafluoroacetone (CF ３ C(=O)CF ３ ), trifluoroacetaldehyde (CF ３ The etching method according to claim 1, wherein the material is C(=O)H, or fluorocarbonyl isocyanate (FC(=O)N=C=O).

8. The isocyanate compound represented by the general formula [3] is fluorosulfonyl isocyanate (FS(=O) ２ The etching method according to claim 1, wherein N=C=O.

9. The etching method according to claim 1, wherein the etching is performed by placing the substrate in a chamber, and the step of subjecting the chamber to a reduced pressure state.

10. The etching method according to claim 1, wherein the (I) HF gas and the (II) compound are simultaneously brought into contact with the substrate.

11. The etching method according to claim 1, comprising: (I) a first etching step of bringing the HF gas into contact with the substrate; and a second etching step of bringing the compound (II) into contact with the substrate.

12. The etching method according to claim 11, wherein etching is performed by repeating the first etching step and the second etching step.

13. The etching method according to claim 11, wherein the first etching step is performed after the second etching step is performed.

14. The aforementioned film containing Si and O is silicon dioxide (SiO ２ The etching method according to claim 1, wherein the film is a film.

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

16. In the aforementioned substrate, the film containing Si and O is silicon dioxide (SiO ２ The etching method according to claim 1, wherein the film containing Si and N is a silicon nitride (SiN) film, the silicon nitride film is adjacent to the silicon oxide film, and both the silicon oxide film and the silicon nitride film are exposed.

17. A method for manufacturing a semiconductor device, comprising the step of selectively etching a silicon nitride film on a substrate having a silicon nitride film and a silicon oxide film by applying the etching method described in any one of claims 1 to 15.

18. A mounting platform on which the circuit board is placed, (I) HF gas supply unit that supplies HF gas, (II) A gas compound (II) supply unit that supplies a gas of at least one compound selected from the group consisting of a sulfonyl compound represented by the following general formula [1], a carbonyl compound represented by the following general formula [2], a sulfonyl isocyanate compound represented by the following general formula [3], and an isocyanate compound represented by the following general formula [4], An etching apparatus equipped with the following: R １ -S(=O) ２ -X [1] (In general formula [1], R １ (where X is a linear or branched alkyl group or halogen atom having 1 to 6 carbon atoms, in which some or all of the hydrogen atoms may be replaced by fluorine atoms, and X is a halogen atom.) R ２ -C(=O)-R ３ [2] (In general formula [2], R ２ and R ３ Each of these is independently a linear or branched alkyl group, hydrogen atom, halogen atom, or isocyanate group having 1 to 6 carbon atoms, in which some or all of the hydrogen atoms may be substituted with fluorine atoms. R ４ -S(=O) ２ N=C=O [3] (In general formula [3], R ４ This refers to a linear or branched alkyl group or halogen atom having 1 to 6 carbon atoms, in which some or all of the hydrogen atoms may be replaced by fluorine atoms. R ５ -N=C=O [4] (In general formula [4], R ５ This refers to a linear or branched alkyl group having 1 to 10 carbon atoms, in which some or all of the hydrogen atoms may be substituted with fluorine atoms.

19. (I) HF gas and (II) At least one compound selected from the group consisting of a sulfonyl compound represented by the following general formula [1], a carbonyl compound represented by the following general formula [2], a sulfonyl isocyanate compound represented by the following general formula [3], and an isocyanate compound represented by the following general formula [4], Etching gas containing [this substance]. R １ -S(=O) ２ -X [1] (In general formula [1], R １ X is a linear or branched alkyl group having 1 to 6 carbon atoms, or a halogen atom, in which some or all of the hydrogen atoms may be replaced by fluorine atoms. R ２ -C(=O)-R ３ [2] (In general formula [2], R ２ and R ３ Each of these is independently a linear or branched alkyl group, hydrogen atom, halogen atom, or isocyanate group having 1 to 6 carbon atoms, in which some or all of the hydrogen atoms may be substituted with fluorine atoms. R ４ -S(=O) ２ N=C=O [3] (In general formula [3], R ４ This refers to a linear or branched alkyl group or halogen atom having 1 to 6 carbon atoms, in which some or all of the hydrogen atoms may be replaced by fluorine atoms. R ５ -N=C=O [4] (In general formula [4], R ５ This refers to a linear or branched alkyl group having 1 to 10 carbon atoms, in which some or all of the hydrogen atoms may be substituted with fluorine atoms.