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

Abstract

The invention provides an etching method capable of selectively etching a film containing Si and O and not containing N, a method for manufacturing a semiconductor device using the etching method, an etching apparatus, a surface treatment gas composition, and an etching gas composition containing a surface treatment material. The present invention relates to an etching method in which (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material are brought into contact with a substrate having a film containing at least Si and O and not containing N and a film containing at least Si and N, and the film containing at least Si and N is selectively etched.

Description

Technical Field

[0001] This invention relates to etching methods, methods for manufacturing semiconductor devices, etching apparatus, surface treatment gas compositions, and etching gas compositions containing surface treatment materials. Background Technology

[0002] In the manufacturing process of semiconductor devices, there is a process of etching silicon oxide films that exist on the surface of semiconductor wafers in the form of CVD-based oxide films, thermal oxide films, or natural oxide films. As etching methods for such silicon oxide films, wet etching using chemical solutions or plasma etching using reactive gas plasma are performed.

[0003] However, wet etching can easily cause adverse effects from the etching solution on components that are not the object being etched. Additionally, plasma etching can cause electrical damage to the wafer due to the plasma.

[0004] To address these issues, attempts have been made to perform dry etching without using plasma. For example, Patent Document 1 discloses a method that performs dry etching by reacting gaseous hydrogen fluoride and gaseous organic amine compounds with silicon oxide without a plasma state.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2020 / 054476 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] While the method described in Patent Document 1 enables dry etching of silicon oxide without the presence of a plasma state, the inventors have found through intensive research that there is room for improvement in selectively etching films containing Si and O but not N.

[0010] In order to solve the aforementioned problems newly discovered by the inventors, the object of the present invention is to provide an etching method capable of selectively etching a film containing Si and O but not N, a method for manufacturing a semiconductor device using the etching method, an etching apparatus, a surface treatment gas composition, and an etching gas composition containing a surface treatment material.

[0011] Technical means to solve the problem

[0012] The inventors discovered through intensive research that by 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 but not N, and a film containing at least Si and N, the film containing Si and O but not N can be selectively etched, thus completing the present invention.

[0013] That is, the present invention (1) relates to an etching method in which (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material are brought into contact with a substrate having a film containing at least Si and O and not containing N and a film containing at least Si and N, and the film containing Si and O and not containing N is selectively etched.

[0014] This invention (2) relates to the etching method of this invention (1), wherein the surface treatment material chemically modifies the surface of the film containing Si and N.

[0015] This invention (3) relates to the etching method of this invention (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.

[0016] The present invention (4) relates to the etching method of any one of the present invention (1) to (3), wherein the surface treatment material is a compound represented by general formula [A].

[0017] RX [A]

[0018] (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).

[0019] This invention (5) relates to the etching method described in this invention (4), wherein R in the general formula [A] is a group that does not react with HF.

[0020] The present invention (6) relates to the etching method described in the present invention (5), wherein R in the general formula [A] is a group that does not contain amino and / or hydroxyl groups.

[0021] This invention (7) relates to the etching method described in this invention (4), wherein R in the general formula [A] is an electron-withdrawing group.

[0022] This invention (8) relates to the etching method described in this invention (7), wherein R in the general formula [A] is XSO2- (X is a halogen atom), XCO- (X is a halogen atom) or C. n R 1 2n＋1 SO2-(R1 Whether they are the same or different, they are hydrogen atoms or halogen atoms, and n is an integer less than 6.

[0023] This invention (9) relates to the etching method described in this invention (7), wherein R in the general formula [A] is FSO2-, FCO-, CF3SO2- or CH3SO2-.

[0024] This invention (10) relates to the etching method described in this invention (4), wherein R in the general formula [A] is C n R 2 2n＋1 -(R 2 Whether they are the same or different, whether they are hydrogen atoms or halogen atoms, n is an integer less than 6) or (C n R 3 2n＋1 )3Si-(R 3 Whether they are the same or different, they are hydrogen atoms or halogen atoms, and n is an integer less than 6.

[0025] This invention (11) relates to the etching method described in this invention (4), wherein R in the general formula [A] is an alkyl group having 6 or fewer carbon atoms or (CH3)3Si-.

[0026] The present invention (12) relates to the etching method of any one of the present invention (1) to (11), wherein the etching gas composition further comprises at least one selected from the group consisting of inactive gases, NH3, organic amine compounds and alcohols.

[0027] The present invention (13) relates to the etching method of any one of the present inventions (1) to (12), wherein the film containing Si and O and not containing N is selectively etched without the presence of a plasma state.

[0028] The present invention (14) relates to an etching method according to any one of the present invention (1) to (13), wherein the etching gas composition (I) containing HF gas and the surface treatment gas composition (II) containing surface treatment material are simultaneously in contact with the substrate.

[0029] The present invention (15) relates to an etching method according to any one of the present invention (1) to (13), comprising: a surface treatment step of contacting the surface treatment gas composition comprising the surface treatment material of (II) with the substrate; and an etching step of contacting the etching gas composition comprising HF gas of (I) with the substrate after performing the surface treatment step.

[0030] The present invention (16) relates to the etching method of any one of the present invention (1) to (15), wherein the substrate temperature during etching is 20 to 300°C.

[0031] The present invention (17) relates to the etching method of any one of the present invention (1) to (16), wherein the pressure during etching is 1 Pa to 10 kPa.

[0032] The present invention (18) relates to the etching method of any one of the present inventions (1) to (17), wherein the pressure during etching is 1 Pa or more and less than 1 kPa.

[0033] The present invention (19) relates to the etching method of any one of the present inventions (1) to (18), wherein the film containing Si and O but not N is a silicon oxide (SiO) film.

[0034] The present invention (20) relates to the etching method of any one of the present inventions (1) to (19), wherein the film containing Si and N is a silicon nitride (SiN) film.

[0035] The present invention (21) relates to an etching method according to any one of the present inventions (1) to (20), wherein, in 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.

[0036] The present invention (22) relates to a method for manufacturing a semiconductor device, comprising the following steps: for a substrate having a film containing at least Si and O but not N and a film containing at least Si and N, selectively etching the film containing Si and O but not N by applying the etching method of any one of the present invention (1) to (21).

[0037] The present invention (23) relates to a method for manufacturing a semiconductor device, comprising the following steps: selectively etching the silicon oxide film by applying the etching method described in any one of the present invention (1) to (21) to a substrate having a silicon nitride film and a silicon oxide film.

[0038] The present invention (24) relates to an etching apparatus comprising:

[0039] A stage on which a substrate is placed;

[0040] (I) An HF gas supply unit that supplies HF gas to the substrate; and

[0041] (II) A surface treatment gas supply unit that supplies the substrate with a surface treatment gas composition containing a surface treatment material.

[0042] The present invention (25) relates to a surface treatment gas composition comprising a surface treatment material.

[0043] The present invention (26) relates to an etching gas composition containing a surface treatment material, comprising: HF gas and a surface treatment material.

[0044] The effects of the invention

[0045] The etching method of the present invention is as follows: (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material are brought into contact with a substrate having a film containing at least Si and O but not N, and the film containing at least Si and N, thereby selectively etching the aforementioned film containing Si and O but not N. Because the surface treatment gas composition containing (II) a surface treatment material is used in conjunction with (I) the etching gas composition containing HF gas, it is possible to selectively etch the film containing Si and O but not N.

[0046] The semiconductor device manufacturing method of the present invention includes the following steps: for a substrate having a film containing at least Si and O but not N, and a film containing at least Si and N, selectively etching the film containing Si and O but not N using the etching method of the present invention; or the semiconductor device manufacturing method includes the following steps: for a substrate having a silicon nitride film and a silicon oxide film, selectively etching the silicon oxide film using the etching method of the present invention. Because the semiconductor device manufacturing method of the present invention includes the etching step of applying the etching method of the present invention, it is possible to selectively etch the film containing Si and O but not N (e.g., a silicon oxide film) on the semiconductor substrate, thereby enabling the manufacture of high-quality semiconductor devices.

[0047] The etching apparatus of the present invention comprises:

[0048] A stage on which a substrate is placed;

[0049] (I) An HF gas supply unit that supplies HF gas to the substrate; and

[0050] (II) A surface treatment gas supply unit that supplies the substrate with a surface treatment gas composition containing a surface treatment material.

[0051] Because of the use of (I) HF gas with (II) a surface treatment gas composition containing surface treatment materials, it is possible to selectively etch films containing Si and O but not N.

[0052] Since the surface treatment gas composition of the present invention contains surface treatment materials, it is possible to selectively etch films containing Si and O but not N.

[0053] Since the etching gas composition containing surface treatment material of the present invention includes HF gas and surface treatment material, it is possible to selectively etch films containing Si and O but not N. Attached Figure Description

[0054] Figure 1 This is a schematic diagram illustrating an example of the test results when CF3SO2F (TfF), used as a surface treatment material, is brought into contact with a SiN film.

[0055] Figure 2 This is a schematic diagram illustrating an example of the test results when CF3SO2F (TfF), used as a surface treatment material, is brought into contact with a SiO2 film.

[0056] Figure 3 This is a schematic diagram illustrating an etching apparatus according to one embodiment of the present invention. Detailed Implementation

[0057] The present invention will now be described in detail, but the description of the constituent elements described below is only one example of an embodiment of the present invention and is not limited to these specific contents. Various changes can be made within its scope.

[0058] In this specification, unless otherwise specified, the notation "X~Y" in the description of numerical ranges means above X and below Y. For example, "1~5 mass%" means "more than 1 mass% and less than 5 mass%".

[0059] <Etching Method>

[0060] The etching method of the present invention is characterized in that (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material are brought into contact with a substrate having a film containing at least Si and O and not containing N, and the film containing at least Si and N, and the film containing Si and O and not containing N is selectively etched.

[0061] As a film that contains at least Si and O but no N (also simply referred to as a film containing Si and O), silicon oxide (SiO₂, where SiO does not represent the stoichiometry of the elements, but refers to a film containing silicon atoms and oxygen atoms) can be listed as an example. x (x is 1 or more and 2 or less, for example, SiO2 film).

[0062] In this specification, a membrane containing at least Si and O but not N means that, in 100% by mass of the membrane, the N content 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.

[0063] As a film containing at least Si and N (or simply referred to as a film containing Si and N), silicon nitride (SiN, where SiN does not refer to the stoichiometry of the elements, but rather to a film containing silicon atoms and nitrogen atoms). For example, SiN x (x is 0.3 or higher and 9 or lower) and Si3N4) films, silicon oxycarbonate (SiOCN, where SiOCN does not represent the stoichiometry of the elements, but refers to films containing silicon atoms, oxygen atoms, carbon atoms, and nitrogen atoms), silicon oxynitride (SiON, where SiON does not represent the stoichiometry of the elements, but refers to films containing silicon atoms, oxygen atoms, and nitrogen atoms. For example, Si4O x N y (x is 3 or more and 6 or less, y is 2 or more and 4 or less) or Si4O5N3 film, silicon carbonitride (SiCN, where SiCN does not represent the stoichiometry of the elements, but refers to a film containing silicon atoms, carbon atoms, and nitrogen atoms. Examples include materials containing 20-50 atomic% silicon, 5-30 atomic% carbon, and 10-30 atomic% nitrogen). Among these, silicon nitride film is preferred.

[0064] The process temperature (substrate temperature) at which the film formed on the substrate comes into contact with (I) the etching gas composition containing 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 being able to selectively etch films containing Si and O more suitably, 130°C to 250°C is preferred, and more preferably 160°C to 230°C. In addition, from the viewpoint of suppressing damage to the film formed on the substrate, 20°C to 200°C, 30°C to 150°C, or 50°C to 120°C may be used. The process temperature at which the film formed on the substrate comes into contact with (II) the surface treatment gas composition containing surface treatment material, and the process temperature at which the film formed on the substrate comes into contact simultaneously with (I) the etching gas composition containing HF gas and (II) the surface treatment gas composition containing surface treatment material are also preferably the above temperatures.

[0065] The etching method of the present invention preferably selectively etches the film containing Si and O without the presence of a plasma state. This is because, in the case of a semiconductor device substrate, there is a concern that exposing it to plasma gas could cause electrical damage to the substrate due to the plasma gas.

[0066] The etching method of the present invention is suitable for selectively etching films containing Si and O. Preferably, the etching method of the present invention selectively etches films containing Si and O, and etches films containing Si and N at a rate of 1.0 nm / min or less. More preferably, the rate is 0.5 nm / min or less.

[0067] In this specification, "selectively etching films containing Si and O" means that the ratio of the etching rate of the film containing Si and O to that of the film containing Si and N (film containing Si and O / film containing Si and N) is 2 or more. The aforementioned 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, even more preferably 350 or more, and even more preferably 400 or more. There is no particular upper limit; for example, it can be 10,000 or less.

[0068] In this specification, the etching rate is a value calculated based on the travel time of the etching gas by measuring the film thickness before and after the etching process using a spectroscopic ellipsometry.

[0069] In the etching method of the present invention, it is preferable to etch the film containing Si and O at a speed of 1.5 nm / min or higher, more preferably 10 nm / min or higher, even more preferably 30 nm / min or higher, particularly preferably 50 nm / min or higher, and the upper limit is not particularly limited, for example, 10 μm / min or lower. Therefore, there is a tendency to be able to selectively etch the film containing Si and O more appropriately.

[0070] In the etching method of the present invention, the substrate is preferably a semiconductor device substrate, such as a silicon substrate, a compound semiconductor substrate, a quartz substrate, or a glass substrate. On the surface of the substrate, in addition to films containing at least Si and O and films containing at least Si and N, polycrystalline silicon films, metal nitride films, silicon films, metal wiring films, etc., may also be formed. A form in which the silicon nitride film is adjacent to the silicon oxide film and both the silicon oxide and silicon nitride films are exposed is suitable for the etching method of the present invention. A form in which the silicon nitride film is adjacent to both the silicon oxide film and the polycrystalline silicon film and both the silicon oxide film, polycrystalline silicon film, and silicon nitride film are exposed is suitable for the etching method of the present invention.

[0071] The substrate is placed, for example, on the stage of the etching apparatus described later, and the substrate, as well as the films containing Si and O and the films containing Si and N formed on the surface of the substrate, are heated by heating the stage.

[0072] There are no particular limitations on the method for forming the film on the substrate surface; examples include chemical vapor deposition (CVD) and sputtering. Furthermore, there are no particular limitations on the thickness of the film containing Si and O, or the thickness of the film containing Si and N; for example, it can be set to a thickness of 0.1 nm to 1 μm.

[0073] The etching method of the present invention preferably involves etching the substrate within a cavity. The etching method of the present invention preferably includes a step of subjecting the cavity to a reduced pressure. The etching method of the present invention further preferably includes the following step: within the cavity, 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, thereby subjecting the cavity to a reduced pressure. This is because byproducts generated during etching can be removed.

[0074] The depressurization state is the state in which the pressure inside the chamber is lower than the pressure during etching (process pressure), which is approximately below 0.133 kPa.

[0075] The etching method of the present invention preferably includes a step of replacing the chamber with an inactive gas. The etching method of the present invention further preferably includes the following step: after contacting (I) an etching gas composition containing HF gas with (II) a surface treatment gas composition containing a surface treatment material, the chamber is replaced with an inactive gas. This is because byproducts generated during etching can be removed.

[0076] The etching method of the present invention can also perform a process of replacing the chamber with an inactive gas after performing a process of putting the chamber under reduced pressure.

[0077] For example, on the surface of SiN, which is an example of a film containing Si and N, an oxide film or a nitrogen oxide film is usually formed. Therefore, in the etching method of the present invention, the process of removing such films can be performed before (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing surface treatment material are brought into contact with the substrate.

[0078] <<(I) Etching Gas Composition Containing HF Gas>>

[0079] The etching gas composition (I) is not particularly limited, as long as it contains HF gas. 100% by volume of the etching gas composition (I) may contain 100% by volume of HF gas. However, the etching gas composition (I) preferably also contains at least one element selected from the group consisting of inactive gases, NH3, organic amine compounds, and alcohols. More preferably, it contains at least one element selected from the group consisting of NH3, organic amine compounds, and alcohols. Even more preferably, it contains at least one element selected from the group consisting of organic amine compounds and alcohols. Particularly preferred is the inclusion of organic amine compounds. This allows for more suitable and selective etching of films containing Si and O. These can be used alone or in combination of two or more.

[0080] Examples of inert gases include Ar, N2, He, Ne, and Kr. These can be used individually or in combination of two or more. Among them, Ar is preferred for its stability and economic efficiency.

[0081] As organic amine compounds, compounds represented by the following general formula (1) can be used. These can be used alone or in combination of two or more.

[0082]

[0083] (In general formula (1), N is a nitrogen atom. R) 1 It is a hydrocarbon group, optionally containing a ring, heteroatom, or halogen atom, with 1 to 10 carbon atoms. R 2 R 3 It is a hydrocarbon group consisting of hydrogen atoms or 1 to 10 carbon atoms, optionally containing a ring, heteroatom, or halogen atom. However, when the number of carbon atoms is 3 or more, the hydrocarbon group may optionally 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, in R... 1 and R 2 When all groups are hydrocarbon groups with 1 or more carbon atoms, R 1 With R 2 It can be directly bonded using a ring structure. Furthermore, in R... 1 Or R 2 In the case of a ring structure with direct double bond bonding, R may not exist. 3 And thus form an aromatic ring. Additionally, R 1 R 2 and R 3 (Optional: either the same hydrocarbon group or different hydrocarbon groups).

[0084] As R 1 Examples include methyl, ethyl, propyl, and butyl groups, where some of the hydrogen atoms constituting these organic groups can be replaced by halogens such as fluorine and chlorine. As R... 2 and R 3 Examples of such organic groups include hydrogen atoms, methyl, ethyl, propyl, butyl, etc., and some or all of the hydrogen atoms constituting these organic groups may be replaced by halogens such as fluorine and chlorine. The organic amines represented by the general formula (1) are optionally heterocyclic amines having a five-membered ring structure or a six-membered ring structure.

[0085] Specific examples of organic amine compounds include: monomethylamine, dimethylamine, trimethylamine, dimethylethylamine, diethylmethylamine, monoethylamine, diethylamine, triethylamine, mono-n-propylamine, di-n-propylamine, monoisopropylamine, diisopropylamine, monobutylamine, dibutylamine, monotert-butylamine, di-tert-butylamine, pyrrolidine, piperidine, piperazine, pyridine, pyrazine, etc. Other specific examples include compounds in which some or all of the CH bonds are CF 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 have conjugate acid pKa of 3.2 or higher than that of HF, can form salts with hydrogen fluoride, and have a certain vapor pressure in the temperature range of 20 to 100°C, thus not decomposing in this temperature range, and can be supplied in gaseous form, which is preferred in this respect.

[0086] In particular, in terms of availability, the organic amine compound is preferably monomethylamine, dimethylamine, trimethylamine, monoethylamine, monopropylamine, isopropylamine, 1,1,1-trifluorodimethylamine, 2,2,2-trifluoroethylamine, or bis(2,2,2-trifluoroethyl)amine.

[0087] Furthermore, regarding the faster etching rate of films containing Si and O, such as silicon oxides, secondary and tertiary amines are preferred as the organic amine compounds. Specific examples of secondary amines include: dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, dibutylamine, and di-tert-butylamine. Specific examples of tertiary amines include: trimethylamine, dimethylethylamine, diethylmethylamine, and triethylamine.

[0088] Examples of alcohols include methanol, ethanol, 1-propanol, and isopropanol. These can be used alone or in combination of two or more.

[0089] In 100 vol% of the etching gas composition (I), the content of HF gas can be 100 vol%, preferably 10 to 90 vol%, more preferably 20 to 80 vol%, even more preferably 30 to 70 vol%, and particularly preferably 40 to 60 vol%.

[0090] In 100% by volume of the etching gas composition (I), the content of inactive gas, NH3, organic amine compound or alcohol (when two or more of them are used in combination, the total content of inactive gas, NH3, organic amine compound and 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.

[0091] If the gas composition of the etching gas composition (I) is within the above range, there is a tendency to be able to selectively etch films containing Si and O more appropriately.

[0092] In the etching gas composition (I) of 100 vol%, the total content of HF gas, inactive gas, NH3, organic amine compound and alcohol is preferably 80 vol% or more, more preferably 90 vol% or more, more preferably 95 vol% or more, particularly preferably 98 vol% or more, and may also be 100 vol%.

[0093] In this specification, the content of each gaseous component in the gas composition can be determined by infrared spectroscopy.

[0094] <<(II) Surface treatment gas compositions containing surface treatment materials>>

[0095] The surface treatment material (II) is not particularly limited, as long as it is a compound capable of treating the surface of a substrate. Preferably, it is a compound capable of chemically modifying the surface of a film containing Si and N, and more preferably, it is a compound capable of chemically modifying the surface of a film containing Si and N as well as the surface of a film containing Si and O. The surface treatment material can be used alone or in combination of two or more.

[0096] In this specification, chemical modification refers to chemical bonding.

[0097] The surface treatment material is preferably a chemically modified surface of a film containing Si and N, and more preferably a chemically modified surface of both a film containing Si and N and a film containing Si and O.

[0098] Figure 1 This is a schematic diagram illustrating an example of the experimental results of contacting a SiN film with CF3SO2F (TfF), which is used as a surface treatment material. According to... Figure 1 It can be seen that by bringing CF3SO2F (TfF), which is a surface treatment material, into contact with the SiN film, the surface of the SiN film is chemically modified.

[0099] in addition, Figure 2 This is a schematic diagram illustrating an example of test results when CF3SO2F (TfF), used as a surface treatment material, is brought into contact with a SiO2 film. According to... Figure 2 It can be seen that by contacting CF3SO2F (TfF), which is a surface treatment material, with the SiO2 film, the surface of the SiO2 film is chemically modified.

[0100] Based on the results of the research conducted by the inventors, it is assumed that the surface of a film containing Si and N has reduced reactivity to HF due to chemical modification, which hinders etching, while the surface of a film containing Si and O has increased reactivity to HF due to chemical modification, which promotes etching.

[0101] It should be noted that, compared to the surface of a film containing Si and O, even after further chemical modification with surface treatment materials, the etching process of a film containing Si and N is intensified due to the aforementioned etching hindering and promoting effects.

[0102] Specific examples of compounds capable of chemically modifying the surfaces of films containing Si and N, as well as the surfaces of films containing Si and O, include compounds represented by the following general formula [A]. These can be used alone or in combination of two or more.

[0103] RX [A]

[0104] (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).

[0105] The R in the general formula [A] is not particularly limited, as long as it is a monovalent group, preferably a group that does not react with HF, and more preferably a group that does not contain amino and / or hydroxyl groups. This allows for the chemical modification of the surfaces of films containing Si and N, as well as films containing Si and O, without hindering the etching of Si and O films using HF gas.

[0106] For the reason that it allows for more suitable and selective etching of films containing Si and O, R in general formula [A] is preferably an electron-withdrawing group. Specific examples of electron-withdrawing groups include XSO2- (X is a halogen atom), XCO- (X is a halogen atom), C... n R 1 2n＋1 SO2-(R 1 Whether they are the same or different, they are hydrogen atoms or halogen atoms, and n is an integer less than 6.

[0107] As X, R 1 Halogen atoms can be fluorine, chlorine, bromine, or iodine. Among them, fluorine atoms are preferred.

[0108] As R 1 Preferably, hydrogen atoms or fluorine atoms.

[0109] The value of n is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.

[0110] Preferred examples of electron-withdrawing groups include FSO2-, FCO-, CF3SO2-, and CH3SO2-. Among these, FSO2- and CF3SO2- are preferred.

[0111] For the reason that it is possible to more appropriately and selectively etch films containing Si and O, R in general formula [A] is also preferably C. n R 2 2n＋1 -(R 2 Whether they are the same or different, whether they are hydrogen atoms or halogen atoms, n is an integer less than 6) or (C n R 3 2n＋1 )3Si-(R 3 Whether the groups are the same or different, they are either hydrogen atoms or halogen atoms, and n is an integer of 6 or less. Preferred specific examples of this group include alkyl groups with 6 or less carbon atoms and (CH3)3Si-.

[0112] R 2 R 3 The halogen atoms also include preferred forms with X, R 1 The halogen atoms are the same.

[0113] As R 2 R 3 Preferably, hydrogen atoms or fluorine atoms, and more preferably hydrogen atoms.

[0114] The value of n is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1.

[0115] In the general formula [A], X is Br, Cl, I, F, -C(O)Cl, -C(O)F, -C(O)H, or -NCO. Therefore, it can chemically react with and modify the surface of films containing Si and N, as well as the surface of films containing Si and O. Preferably, it contains Cl, I, F, -C(O)Cl, or -NCO; more preferably, it contains -C(O)Cl or -NCO; and even more preferably, it contains -NCO.

[0116] Examples of compounds represented by general formula [A] include: CH3I, CH3Br, CH3Cl, CH3F, tBu-NCO, CH3NCO, FSO2NCO, CF3SO2NCO, CH3COCl, CH3COF, CH3COH, CF3SO2F, CF3SO2Cl, CF3SO2Br, CF3SO2I, CH3SO2F, CH3SO2Cl, CH3SO2Br, CH3SO2I, FCOF, FCOCl, FCOBr, FCOI, etc. These can be used alone or in combination of two or more. Among them, CH3I, tBu-NCO, FSO2NCO, CH3COCl, CF3SO2F, and CF3SO2Cl are preferred, and FSO2NCO is even more preferred.

[0117] The surface treatment gas composition (II) is not particularly limited, as long as it contains surface treatment material. 100% by volume of the surface treatment gas composition (II) may contain 100% by volume of surface treatment material, but the surface treatment gas composition (II) may also further contain at least one (preferably an inactive gas) selected from the group consisting of inactive gases, NH3, organic amine compounds, and alcohols. It can be used alone or in combination of two or more. Inactive gases, organic amine compounds, and alcohols are as described in <<(I) Etching Gas Composition Containing HF Gas>>.

[0118] In 100 vol% of the surface treatment gas composition (II), the content of the surface treatment material is preferably 60 vol% or more, more preferably 80 vol% or more, even more preferably 90 vol% or more, particularly preferably 95 vol% or more, and may also be 100 vol%. If the gas composition of the surface treatment gas composition (II) is within the above range, there is a tendency to be able to selectively etch films containing Si and O more appropriately.

[0119] [Etching Method 1]

[0120] First, as an etching method of the present invention, a first etching method in which an etching gas composition containing HF gas (I) and a surface treatment gas composition containing a surface treatment material are simultaneously brought into contact with the substrate will be described. Hereinafter, the etching gas used in the first etching method will be described as an etching gas composition containing a surface treatment material, which is a mixture of the etching gas composition containing HF gas (I) and the surface treatment gas composition containing a surface treatment material (II), and contains at least HF gas and a surface treatment material.

[0121] In the following description, films containing at least Si and O, as well as films containing at least Si and N, will be referred to as etched films.

[0122] It is believed that if (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material are simultaneously brought into contact with the etched film in a heated state, then the surface treatment material of (II) can selectively etch the Si and O film by chemically modifying the surface of the film containing Si and N and the surface of the film containing Si and O. The surface of the film containing Si and N becomes less reactive to HF due to the chemical modification, thus hindering etching, while the surface of the film containing Si and O becomes more reactive to HF due to the chemical modification, thus promoting etching.

[0123] (I) Etching gas compositions containing HF gas, and (II) Surface treatment gas compositions containing surface treatment materials, including preferred forms, are the same as described above.

[0124] The preferred volume ratio of the etching gas composition containing HF gas (I) to the surface treatment gas composition containing the surface treatment material (II) is (I) etching gas composition containing HF gas : (II) surface treatment gas composition containing the surface treatment material = 10 : 0.01 to 10, more preferably 10 : 0.05 to 6, and even more preferably 10 : 0.3 to 3. If the HF gas ratio is too low, the etching rate tends to decrease; if it is too high, it becomes too expensive. Furthermore, even if the amount of the surface treatment gas composition containing the surface treatment material (II) is too high, etching may not be easily achieved.

[0125] Since the surface treatment gas composition containing surface treatment materials (II) is effective even in trace amounts, in 100% by volume of the etching gas composition containing surface treatment materials, the surface treatment gas composition containing surface treatment materials (II) only needs to be 1% by volume or more.

[0126] The etching gas composition containing surface treatment material is a mixture of the etching gas composition containing HF gas (I) and the surface treatment gas composition containing surface treatment material (II), and contains at least HF gas and surface treatment material.

[0127] In the etching gas composition containing surface treatment material, the content of HF gas is preferably 10-80% by volume, more preferably 20-70% by volume, even more preferably 30-60% by volume, and particularly preferably 40-50% by volume.

[0128] In the etching gas composition containing 100% by volume of surface treatment material, the content of 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.

[0129] In 100% by volume of the etching gas composition containing surface treatment material, the content of inactive gas, NH3, organic amine compound or alcohol (when two or more of these are used in combination, the total content of inactive gas, NH3, organic amine compound and alcohol) 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.

[0130] In the etching gas composition containing surface treatment material, the total content of HF gas, surface treatment material, inactive gas, NH3, organic amine compound and alcohol is preferably 80% or more by volume, more preferably 90% or more by volume, more preferably 95% or more by volume, particularly preferably 98% or more by volume, and may also be 100% by volume.

[0131] If the gas composition of the etching gas composition containing the surface treatment material is within the above range, there is a tendency to more appropriately and selectively etch films containing Si and O.

[0132] The first etching method preferably includes: a step of simultaneously contacting the substrate with (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material in a chamber; and a step of placing the chamber under reduced pressure; and etching is performed by repeating these steps. The step of placing the chamber under reduced pressure can be performed instead of the step of replacing the chamber with an inactive gas, or the step of replacing the chamber with an inactive gas can be performed after the step of placing the chamber under reduced pressure. As one embodiment, in the first etching method, it is preferable to perform the step of simultaneously contacting the substrate with (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material in a chamber, followed by the step of placing the chamber under reduced pressure and / or the step of replacing the chamber with an inactive gas.

[0133] [Second Etching Method]

[0134] Secondly, as an etching method of the present invention, a second etching method comprising the following steps will be described: a surface treatment step in which the surface treatment gas composition comprising the surface treatment material of (II) is brought into contact with the substrate; and an etching step in which the etching gas composition comprising HF gas of (I) is brought into contact with the substrate after the surface treatment step.

[0135] If, as a surface treatment step, the surface treatment gas composition containing the surface treatment material (II) is brought into contact with the etched film in a heated state, the following situation occurs: the surface treatment material (II) chemically modifies the surfaces of the films containing Si and N and the films containing Si and O. The surface of the film containing Si and N becomes less reactive to HF due to the chemical modification, hindering etching; the surface of the film containing Si and O becomes more reactive to HF due to the chemical modification, promoting etching. It is believed that subsequently, if, as an etching step, the etching gas composition containing HF gas (I) is brought into contact with the substrate, the Si and O films of the etched film can be selectively etched.

[0136] In the second etching method of the present invention, the above-described process can be repeated multiple times to repeatedly etch the film to be etched. In one etching cycle, since etching can be performed at a certain thickness, by specifying a certain number of cycles, a layer of the required thickness can be precisely etched.

[0137] (I) Etching gas compositions containing HF gas, and (II) Surface treatment gas compositions containing surface treatment materials, including preferred forms, are the same as described above.

[0138] The second etching method preferably involves performing a surface treatment process and an etching process within a chamber, further including a process of bringing the chamber under reduced pressure. Etching is preferably performed by repeatedly performing these processes. A process of replacing the chamber with an inert gas can be performed instead of bringing the chamber under reduced pressure, or the process of replacing the chamber with an inert gas can be performed after bringing the chamber under reduced pressure. As one embodiment, in the second etching method, it is preferable to perform a process of bringing the chamber under reduced pressure and / or replacing the chamber with an inert gas after the surface treatment process, followed by the etching process, and then the process of bringing the chamber under reduced pressure and / or replacing the chamber with an inert gas.

[0139] [Etching apparatus]

[0140] The etching method of the present invention can be implemented, for example, by using the etching apparatus described below. These etching apparatuses are also part of the present invention.

[0141] The etching apparatus of the present invention includes: a stage on which a substrate is placed; an HF gas supply unit that supplies the substrate with (I) HF gas; and a surface treatment gas supply unit that supplies the substrate with (II) a surface treatment gas composition comprising a surface treatment material. The etching apparatus of the present invention may further include an inert gas supply unit that supplies an inert gas into the chamber. Furthermore, the etching apparatus of the present invention may further include an additional gas supply unit that supplies NH3, organic amine compounds, or alcohols into the chamber.

[0142] Figure 3 This is a schematic diagram illustrating an etching apparatus according to one embodiment of the present invention.

[0143] Figure 3 The etching apparatus 100 shown includes: a chamber 110 for mounting a substrate 113; 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; an additional gas supply unit 160 supplying NH3, an organic amine compound, or an alcohol; and a heating mechanism 111 for heating the chamber 110. It should be noted that the etching apparatus 100 may not include the inert gas supply unit 130 and the additional gas supply unit 160.

[0144] Furthermore, the etching apparatus 100 includes a control unit (not shown). This control unit may include, for example, a computer, and includes a program, memory, and CPU. The program includes a series of actions performed by a process group to execute the first etching method or the second etching method. According to the program, the temperature of the substrate 113 is adjusted, the valves of each supply unit are opened and closed, the flow rate of each gas is adjusted, and the pressure in the chamber 110 is adjusted. This program is stored in a computer storage medium, such as an optical disc, hard disk, magneto-optical disk, or memory card, and is installed in the control unit.

[0145] The chamber 110 includes a mounting stage 112 for placing the substrate 113. The chamber 110 is not particularly limited, as long as it is resistant to the HF gas used and can be depressurized to a specified pressure; a typical chamber used in semiconductor etching apparatus is acceptable. Furthermore, the supply pipes and other piping for supplying the etching gas are also not particularly limited, as long as they are resistant to HF gas; general types can be used.

[0146] The HF gas supply unit 140 adjusts the supply amount through valves 143 and 144 and flow adjustment mechanism 142, supplying HF gas from piping 141 and 145 to piping 121.

[0147] The surface treatment gas supply unit 150 adjusts the supply amount through valves 153 and 154 and flow adjustment mechanism 152 to supply the surface treatment gas composition from pipes 151 and 155 to pipe 121.

[0148] The inactive gas supply unit 130 adjusts the supply amount through valves 133 and 134 and flow adjustment mechanism 132, supplying inactive gas from piping 131 and 135 to piping 121.

[0149] The supplementary gas supply unit 160 adjusts the supply amount via valves 163 and 164 and a flow adjustment mechanism 162, supplying NH3, organic amine compounds, or alcohols from pipes 161 and 165 to pipe 161. The supplementary gas supply unit 160 can also supply a mixture of NH3, organic amine compounds, and alcohols. The etching apparatus 100 may have multiple supplementary gas supply units 160.

[0150] A heating mechanism 111 for heating the chamber 110 is disposed outside the chamber 110. Additionally, a heater (not shown) may be disposed inside the mounting stage 112 as a second heating mechanism. It should be noted that when multiple mounting stages are disposed in the chamber 110, by providing a heater to each mounting stage, the temperature of the substrate on each mounting stage can be individually set to a predetermined temperature.

[0151] A gas discharge mechanism for discharging the reacted gas is provided in one of the chambers 110. The vacuum pump 127 of the gas discharge mechanism discharges the reacted gas from the chamber 110 via piping 122. The reacted gas can be recovered by installing a liquid nitrogen cold trap (not shown) between piping 122 and the vacuum pump 127. Valves 125 and 126 can be installed on piping 121 and 122 to adjust the pressure. Additionally, in Figure 3 In this system, the PI123 and 124 series pressure gauges, based on their indicated values, enable the control unit to control each flow adjustment mechanism and each valve.

[0152] Taking the etching apparatus 100 as an example, the etching method will be explained in detail.

[0153] [First etching method using the above-described etching apparatus]

[0154] In the first etching method of the present invention, the etching gas composition (I) containing HF gas and the surface treatment gas composition (II) containing a surface treatment material are simultaneously brought into contact with the substrate. That is, the etching gas composition containing HF gas and the surface treatment material is brought into contact with the film to be etched.

[0155] In the first etching method, firstly, a substrate 113 with an etchable film formed thereon is placed in a chamber 110. The etchable film includes a film containing at least Si and O and a film containing at least Si and N. Secondly, after the vacuum inside 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, the substrate 113 is heated by a heating mechanism 111.

[0156] When the substrate 113 reaches a predetermined temperature, a mixture of HF gas and surface treatment gas is supplied to the piping 121 at a predetermined flow rate from the HF gas supply unit 140 and the surface treatment gas supply unit 150. It should be noted that inactive gas can be supplied to the piping 121 at a predetermined flow rate from the inactive gas supply unit 130. Additionally, NH3, organic amine compounds, or alcohols can be supplied to the piping 121 at a predetermined flow rate from the supplementary gas supply unit 160.

[0157] HF gas and a surface treatment gas composition are mixed in a prescribed manner and supplied to chamber 110. While introducing the mixed etching gas composition containing the surface treatment material into chamber 110, the pressure inside chamber 110 is controlled at a prescribed level. Etching is performed by allowing the etching gas composition containing the surface treatment material to react with the film to be etched for a prescribed time. In this etching method, etching can be performed without plasma, eliminating the need to excite the etching gas composition containing the surface treatment material with plasma. The flow rate of the etching gas composition containing the surface treatment material can be appropriately set based on the chamber volume and pressure.

[0158] It should be noted that etching accompanied by plasma refers to adding a gas of about 0.01 to 1.33 kPa into the interior of the reaction device, applying high-frequency power to the outer coil or the counter electrode, generating a low-temperature gas plasma in the reaction device, and etching is performed by active chemical species such as ions or free radicals generated therein.

[0159] In the etching method of the present invention, the gas is brought into contact without being accompanied by a plasma state, and dry etching is performed without generating the gas plasma.

[0160] After the etching process is completed, heating using heating mechanism 111 is stopped to cool down, and vacuum pump 127 is stopped. The vacuum is then released by purging with inactive gas. As described above, by using the first etching method of the etching apparatus, films containing Si and O can be selectively etched.

[0161] (Etching conditions in the first etching method)

[0162] In the first etching method of the present invention, the temperature of the etched film when the etching gas composition containing the surface treatment material is brought into contact with the etched film is simply the temperature at which the etching gas composition containing the surface treatment material reacts with the film containing Si and O. Particularly preferred is that the temperature of the etched film to be removed is the process temperature (substrate temperature). The substrate temperature is substantially equal to the temperature of the etched film, but during the etching reaction, the substrate temperature or the temperature of the etched film may sometimes rise due to the heat of reaction. In the present invention, it is preferable that at least the process temperature (substrate temperature), i.e., the temperature inside the chamber or the temperature of the stage on which the substrate is placed, is within the aforementioned temperature range.

[0163] In addition, when the etching gas composition containing the surface treatment material is brought into contact with the etched film, the pressure (the pressure during etching) in the chamber where the substrate on which the etched film is formed is not particularly limited, and is usually in the pressure range of 0.1 Pa to 101.3 kPa.

[0164] In terms of the tendency to more appropriately and selectively etch films containing Si and O, the pressure in the chamber during the etching process 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.

[0165] There is no particular limitation on the processing time of the etching process, but considering the efficiency of semiconductor device manufacturing processes, it is preferably within 60 minutes. Here, the processing time of the etching process refers to the time from the introduction of an etching gas composition containing a surface treatment material into the chamber where the substrate is mounted, to the exhaust of the etching gas composition containing the surface treatment material from the chamber by means of a vacuum pump or the like to complete the etching process.

[0166] [Second etching method using the etching apparatus]

[0167] The second etching method of the present invention includes: a surface treatment step in which the surface treatment gas composition comprising a surface treatment material (II) is brought into contact with the substrate; and an etching step in which, after the surface treatment step is performed, the etching gas composition comprising HF gas (I) is brought into contact with the substrate.

[0168] In the second etching method, firstly, a substrate 113 is placed in a chamber 110, the substrate 113 having films containing at least Si and O and films containing at least Si and N formed thereon. Secondly, after the vacuum inside the chamber 110, pipes 121 and 122, pipes 131 and 135, pipes 141 and 145, and pipes 151 and 155 is evacuated to a specified pressure by a vacuum pump 127, the substrate 113 is heated by a heating mechanism 111.

[0169] When the substrate 113 reaches a predetermined temperature, firstly, a surface treatment gas composition is supplied to the piping 121 at a predetermined flow rate from the surface treatment gas supply unit 150. It should be noted that an inactive gas can also be supplied to the piping 121 at a predetermined flow rate from the inactive gas supply unit 130. While introducing the surface treatment gas composition or a combination of the surface treatment gas composition and an inactive gas 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 onto the etched film (reaction).

[0170] After the gas containing the surface treatment gas composition is evacuated under vacuum, HF gas is supplied to pipe 121 at a predetermined flow rate from HF gas supply unit 140. It should be noted that inactive gas can be supplied to pipe 121 at a predetermined flow rate from inactive gas supply unit 130. Additionally, NH3, organic amine compounds, or alcohols can be supplied to pipe 121 at a predetermined flow rate from supplementary gas supply unit 160. While introducing HF gas or HF gas and other gases into chamber 110, the pressure inside chamber 110 is controlled at a predetermined level. By introducing HF gas into chamber 110 at predetermined times, the Si and O-containing film of the etched film can be selectively etched.

[0171] In the second etching method of the present invention, the process of having a surface treatment process and an etching process as one cycle can be repeated multiple times. The surface treatment process involves introducing a surface treatment gas composition into the chamber 110, and the etching process involves introducing HF gas into the chamber 110.

[0172] In the second etching method of the present invention, by setting the etching conditions of one cycle to predetermined conditions, the thickness of the etchable film that can be etched in one cycle can be controlled. Therefore, by setting the thickness of the etchable film that can be etched in one cycle to be thinner, the etching thickness can be precisely controlled.

[0173] In the second etching method of the present invention, it is preferable to perform a process to bring the chamber into a depressurized state after the surface treatment process, and then perform the etching process. Furthermore, it is preferable to perform the process to bring the chamber into a depressurized state in each cycle.

[0174] It should be noted that in the second etching method, etching can also be performed without plasma, without the need to excite the etching gas using plasma or similar methods. The flow rates of the HF gas and surface treatment gas composition can be appropriately set based on the chamber volume and pressure.

[0175] Thus, in the second etching method of the present invention using the etching apparatus, the gas can be made to come into contact without being accompanied by a plasma state, and dry etching can be performed without generating the gas plasma.

[0176] After the etching process is completed, heating using heating mechanism 111 is stopped to cool down, and vacuum pump 127 is stopped. The vacuum is then released by purging with an inactive gas. By using the second etching method of the etching apparatus, films containing Si and O can be selectively etched.

[0177] (Etching conditions in the second etching method)

[0178] In the second etching method of the present invention, the temperature of the etched film is only required to be the temperature at which (II) the surface treatment gas composition containing the surface treatment material reacts with the film containing Si and N and the film containing Si and O, and (I) the temperature at which the etching gas composition containing HF gas reacts with the film containing Si and O. Particularly preferred is that the temperature of the etched film to be removed is the process temperature (substrate temperature). Ideally, the temperature of the etched film in the surface treatment step and the etching step should be the same. The substrate temperature is substantially equal to the temperature of the etched film, but during the etching reaction, the substrate temperature and the temperature of the etched film may sometimes rise due to the heat of reaction. In the present invention, it is preferable that at least the process temperature (substrate temperature), i.e., the temperature inside the chamber or the temperature of the stage on which the substrate is placed, is within the stated temperature range.

[0179] In addition, the pressure inside the chamber during the etching process is the same as the conditions described in the etching conditions of the first etching method.

[0180] On the other hand, the pressure inside the chamber during the surface treatment process is preferably 1 Pa to 100 kPa, more preferably 10 Pa to 10 kPa, and even more preferably 10 Pa to 2 kPa. Alternatively, it can be 1 kPa to 20 kPa. Therefore, there is a tendency to be able to selectively etch films containing Si and O more appropriately.

[0181] There is no particular limitation on the processing time in the surface treatment and etching processes. The processing time in one cycle of the surface treatment process is preferably within 60 minutes, and the processing time in one cycle of the etching process is preferably within 60 minutes. Here, the processing time of the etching process refers to the time from the introduction of etching gas into the chamber where the substrate is placed, to the exhaust of the etching gas in the chamber by means of a vacuum pump or the like, in order to complete the etching process.

[0182] [Semiconductor device manufacturing methods]

[0183] The etching method of the present invention described above can be used as follows: for a substrate having at least a film containing Si and O and at least a film containing Si and N (preferably a substrate having a silicon nitride film and a silicon oxide film), the etching method is applied to selectively etch the film containing Si and O (preferably a silicon oxide film). By selectively etching the film containing Si and O (preferably a silicon oxide film) on the substrate using the etching method of the present invention, semiconductor devices can be manufactured economically.

[0184] The method for manufacturing the semiconductor device of the present invention is characterized by comprising the following steps: selectively etching the film containing Si and O (preferably a silicon oxide film) using the etching method on a substrate having at least a film containing Si and O and at least a film containing Si and N. The step of selectively etching the film containing Si and O (preferably a silicon oxide film) without plasma state by reacting HF gas and a surface treatment material (II) with the substrate having at least a film containing Si and O and at least a film containing Si and N (preferably a silicon nitride film and a silicon oxide film) can be performed by the etching method of the present invention. The substrate may further have a polycrystalline silicon film. The substrate is preferably a silicon substrate.

[0185] Example

[0186] The present invention will now be described in detail with reference to the embodiments, but the present invention is not limited to these embodiments.

[0187] First, silicon wafers with SiN films and SiO2 films were prepared as substrates to be processed. The film thickness before and after etching was measured using a spectroscopic ellipsometry (manufactured by Semilab Japan KK Co., Ltd., product name: SE-2000) to determine the etching amount and SiO2 / SiN selectivity.

[0188] (Simultaneous Circulation Law)

[0189] [Example 1-1]

[0190] use Figure 3The etching apparatus 100 is shown. First, the substrate to be processed is placed on the stage in the chamber. After the chamber is fully evacuated, the temperature of the stage is set to 120°C. The temperature of the substrate is the same as the temperature of the stage, which is essentially equal to the temperature of the film to be etched. Next, N2 gas is circulated in the chamber to dry it thoroughly. Then, HF gas, trimethylamine gas, and CH3COCl gas are circulated in the chamber for 1 minute. The gas flow rate and pressure in the chamber at this time are shown in Table 1. Finally, the chamber is evacuated, replaced with N2 gas, and the substrate to be processed is removed. The results are shown in Table 1. Silicon wafers with SiN films and silicon wafers with SiO2 films, which serve as the substrates to be processed, are all placed in the same chamber and etched simultaneously. It should be noted that the etching gas composition (I) consists of HF gas and trimethylamine gas, the surface treatment gas composition (II) consists of CH3COCl gas, and the etching gas composition containing surface treatment material consists of HF gas, trimethylamine gas, and CH3COCl gas.

[0191] [Examples 1-2] to [Examples 1-4], [Comparative Example 1-1]

[0192] Except for the conditions shown in Table 1, the experiment was conducted under the same conditions as in Example 1-1. The results are shown in Table 1.

[0193] (Alternating circulation method)

[0194] [Example 2-1]

[0195] First, the substrate to be processed is placed on the stage inside the chamber. After the chamber is fully evacuated, the stage temperature is set to 120°C. Then, N2 gas is circulated inside the chamber for thorough drying.

[0196] (A) Subsequently, under the conditions shown in Table 2, CH3I gas was allowed to circulate in the chamber, followed by thorough evacuation and replacement with N2 gas.

[0197] (B) Next, under the conditions shown in Table 2, after HF gas and trimethylamine gas are circulated in the chamber, a full vacuum is drawn and replaced with N2 gas.

[0198] Finally, the processed substrate was removed from the chamber. The results are shown in Table 2. It should be noted that the etching rate was determined based on the flow time of the etching gas. Silicon wafers with SiN films and SiO2 films, which served as the processed substrates, were placed in the same chamber and processed simultaneously. Furthermore, conditions not explicitly described were set to the same conditions as in Examples 1-1.

[0199] [Example 2-2] to [Example 2-24], [Comparative Example 2-1] to [Comparative Example 2-3]

[0200] Except for the conditions shown in Table 2, the experiment was conducted under the same conditions as in Example 2-1. The results are shown in Table 2.

[0201] [Table 1]

[0202]

[0203] [Table 2]

[0204]

[0205] According to Tables 1 and 2, in the embodiments where (I) an etching gas composition containing HF gas and (II) a surface treatment gas composition containing a surface treatment material are brought into contact with a substrate having a film containing at least Si and O and a film containing at least Si and N, the film containing Si and O can be selectively etched. Therefore, it can be seen that by using the surface treatment gas composition containing (II) a surface treatment material in conjunction with the etching gas composition containing (I) HF gas, the film containing Si and O can be selectively etched.

[0206] 100: Etching device

[0207] 110: Chamber

[0208] 111: Heating mechanism

[0209] 112: Platform

[0210] 113:Substrate

[0211] 121, 122:Piping

[0212] 123, 124: PI (piston piezometer)

[0213] 125, 126: Valves

[0214] 127: Vacuum pump

[0215] 130: Inactive Gas Supply Department

[0216] 131, 135:Piping

[0217] 132: Flow Adjustment Agency

[0218] 133, 134: Valves

[0219] 140: HF Gas Supply Department

[0220] 141, 145:Piping

[0221] 142: Flow Adjustment Mechanism

[0222] 143, 144: Valves

[0223] 150: Surface Treatment Gas Supply Section

[0224] 151, 155:Piping

[0225] 152: Flow Adjustment Agency

[0226] 153, 154: Valves

[0227] 160: Additional Gas Supply Department

[0228] 161, 165:Piping

[0229] 162: Flow Adjustment Mechanism

[0230] 163, 164: Valves

Claims

1. An etching method, wherein, The etching gas composition containing (I) HF gas and the surface treatment gas composition containing the surface treatment material are brought into contact with a substrate having a film containing at least Si and O and not N, and the film containing at least Si and N, to selectively etch the film containing Si and O and not N.

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, as well as 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 the general formula [A]. RX [A] In the 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, The R in the general formula [A] is a group that does not react with HF.

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

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

8. The etching method according to claim 7, wherein, R in the general formula [A] is: XSO2-, where X is a halogen atom; XCO-, where X is a halogen atom; or C n R 1 2n＋1 SO2-, where R 1 Whether they are the same or different, they are hydrogen atoms or halogen atoms, and n is an integer less than 6.

9. The etching method according to claim 7, wherein, The R in the general formula [A] is FSO2-, FCO-, CF3SO2-, or CH3SO2-.

10. The etching method according to claim 4, wherein, R in the general formula [A] is: C n R 2 2n＋1 -, where R 2 Same or different, is a hydrogen atom or a halogen atom, n is an integer less than 6, or (C n R 3 2n＋1 )3Si-, where R 3 Whether they are the same or different, they are hydrogen atoms or halogen atoms, and n is an integer less than 6.

11. The etching method according to claim 4, wherein, The R in the general formula [A] is an alkyl group with 6 or fewer carbon atoms or (CH3)3Si-.

12. The etching method according to claim 1, wherein, The etching gas composition further comprises at least one selected from the group consisting of inactive gases, NH3, organic amine compounds, and alcohols.

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

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

15. The etching method according to claim 1, comprising: A surface treatment process in which the surface treatment gas composition comprising the surface treatment material (II) is brought into contact with the substrate; and a surface treatment process after the surface treatment process is performed. An etching process in which the etching gas composition containing HF gas in (I) is brought into contact with the substrate.

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

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

18. The etching method according to claim 1, wherein, The etching pressure is above 1 Pa and less than 1 kPa.

19. The etching method according to claim 1, wherein, The film containing Si and O but not 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, In 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 the following steps: selectively etching the film containing Si and O but not N, for a substrate having a film containing at least Si and N and a film containing at least Si and N, using the etching method of any one of claims 1 to 21.

23. A method for manufacturing a semiconductor device, comprising the following steps: selectively etching the 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 stage on which a substrate is placed; (I) An HF gas supply unit that supplies HF gas to the substrate; and (II) A surface treatment gas supply unit that supplies the substrate with a surface treatment gas composition containing a surface treatment material.

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

26. An etching gas composition containing a surface treatment material, comprising: HF gas and the surface treatment material.

Images