Silicon-containing film precursor, composition for forming silicon-containing film, method for producing sulfur-containing siloxane, and method for producing silicon-containing film

Abstract

Provided is a siloxane compound that can be used as a silicon-containing film precursor by means of a sulfur-containing siloxane represented by formula (1), said silicon-containing film precursor being capable of forming a film by means of an atomic layer deposition (ALD) method even under high-temperature conditions in the formation of a silicon-containing film. [In formula (1), R1 to R8 are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms when each appears, R1 to R8 are each optionally bonded to each other to form a ring, X1 to X3 are each independently an oxygen atom or a sulfur atom when each appears, and n is an integer of 0 to 2. ] # imgabs0 #

Description

Technical Field

[0001] The technical field of the present disclosure relates to a sulfur-containing siloxane and a method for manufacturing a silicon-containing film using the compound, etc. Background Art

[0002] In the fabrication of semiconductor devices, silicon-containing thin films are fabricated into various forms of thin films such as silicon films, silicon oxide films, silicon nitride films, silicon carbonitride films, and silicon oxynitride films through various vapor deposition processes and are applied in various fields. Among them, silicon oxide films and silicon nitride films have very excellent isolation characteristics and oxidation resistance, and thus function as insulating films, intermetal dielectrics, seed layers, spacers, hard masks, trench isolation, anti-diffusion films, etch stop layers, and protective film layers in the fabrication of devices.

[0003] In recent years, with the miniaturization of components, the increase in aspect ratio, and the diversification of component materials, a technique for film formation using atomic layer deposition (ALD) method capable of forming a uniform film has been required. In addition, in recent years, high-quality films with few impurities and excellent electrical characteristics have been needed. As one of the solutions for forming high-quality films, a method of film formation at a high temperature of 500 °C or higher has attracted attention. However, among conventional film-forming materials, most decompose at high temperatures, and it is difficult to perform film formation using the atomic layer deposition (ALD) method. If decomposition occurs, it is difficult to control film formation by itself, and thus it is difficult to form a uniform film, and it may not be possible to achieve high aspect ratio film formation accompanying miniaturization, etc. Therefore, a material that does not decompose even under high temperature conditions and can be used for film formation by the ALD method is sought.

[0004] As an example of a conventional film-forming material, in Patent Document 1, the following method was proposed: using bis(diethylamino)silane (BDEAS), which is an aminosilane compound, as a silicon source by the atomic layer deposition (ALD) method to form a uniform silicon oxide film.

[0005] In Patent Document 2, the following method was proposed: using 2-dimethylamino-2,4,6,8-tetramethylcyclotetrasiloxane, which is an aminosilane compound, as a silicon source to form a uniform silicon oxide film at a high deposition rate by the atomic layer deposition (ALD) method.

[0006] In addition, in Patent Document 3, the following method was proposed: using dimethylaminotrimethylsilane (DMATMS), which is an aminosilane compound, as a silicon source by the atomic layer deposition (ALD) method to form a uniform silicon oxide film at a high temperature.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Japanese Patent Application Laid-Open No. 2008-533731

[0010] Patent Document 2: Japanese Patent Application Laid-Open No. 2018-154615

[0011] Patent Document 3: Japanese Patent Application Laid-Open No. 2020-038978 Summary of the Invention

[0012] Problems to be Solved by the Invention

[0013] However, bis(diethylamino)silane described in Patent Document 1 can form a silicon oxide film by atomic layer deposition (ALD) at 200 to 400°C, and 2-dimethylamino-2,4,6,8-tetramethylcyclotetrasiloxane described in Patent Document 2 can form a silicon oxide film by atomic layer deposition (ALD) at 100 to 300°C. However, since the temperature range is low, when forming a film at a high temperature of 500°C or higher, the film-forming material may decompose and a uniform film may not be formed. In addition, dimethylaminotrimethylsilane described in Patent Document 3 can form a silicon oxide film by the ALD method at 500 to 650°C, which is a higher temperature than bis(diethylamino)silane described in Patent Document 1 and 2-dimethylamino-2,4,6,8-tetramethylcyclotetrasiloxane described in Patent Document 2, but the high-temperature conditions are still not sufficient.

[0014] The present disclosure has been conceived under such circumstances, and its main technical problem is to provide a siloxane compound that can be used as a novel silicon-containing film precursor, and the novel silicon-containing film precursor can form a film by the atomic layer deposition (ALD) method even under high-temperature conditions.

[0015] Solutions to the Problems

[0016] Conventionally, an aminosilane compound in which an amino group is bonded to a silicon atom has generally been used as a precursor (silicon-containing film precursor) for forming a silicon-containing film. However, the present inventors have conducted in-depth research and found that in order to obtain the desired effect, it is useful to use a thiosilane compound in which a sulfur atom is bonded to a silicon atom as a silicon-containing film precursor. In particular, it has been found that by using a specific compound in which a sulfur atom is bonded to a silicon atom in a siloxane structure (—Si—O—) as a silicon-containing film precursor, film formation by the atomic layer deposition (ALD) method can be achieved under higher temperature conditions, and thus the present disclosure has been completed.

[0017] An example of an embodiment in the present disclosure is as follows.

[0018] [Item 1] A silicon-containing film precursor comprising a sulfur-containing siloxane represented by the formula (1).

[0019]

[0020] [In formula (1), R 1 ~R 8 is independently, each time it appears, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. R 1 ~R 8 optionally bond to each other to form a ring. X 1 ~X 3 is independently, each time it appears, an oxygen atom or a sulfur atom, and n is an integer from 0 to 2.]

[0021] [Item 2] The silicon-containing film precursor according to Item 1, wherein X 1 ~X 3 is an oxygen atom.

[0022] [Item 3] The silicon-containing film precursor according to Item 1 or 2, wherein the sulfur-containing siloxane is represented by formula (2).

[0023]

[0024] [In formula (2), R 1 ~R 8 is independently, each time it appears, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, and n is an integer from 0 to 2.]

[0025] [Item 4] The silicon-containing film precursor according to any one of Items 1 to 3, wherein R 1 ~R 8 is independently, each time it appears, an alkyl group having 1 to 5 carbon atoms.

[0026] [Item 5] The silicon-containing film precursor according to any one of Items 1 to 4, wherein the sulfur-containing siloxane is 2,2,4,4,6,6,8,8 - octamethyl - 1,3,5 - trioxa - 7 - thia - 2,4,6,8 - tetrasilacyclooctane represented by formula (3).

[0027]

[0028] [Item 6] The silicon-containing film precursor according to any one of Items 1 to 5, wherein the silicon-containing film is formed by chemical vapor deposition.

[0029] [Item 7] The silicon-containing film precursor according to any one of Items 1 to 6, wherein the silicon-containing film is formed by atomic layer deposition.

[0030] [Item 8] A composition for forming a silicon-containing film, which contains the sulfur-containing siloxane represented by formula (1).

[0031]

[0032] [In formula (1), R 1 ~R 8 is independently, each time it appears, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. R 1 ~R 8 optionally bond to each other to form a ring. X 1 ~X 3 is independently, each time it appears, an oxygen atom or a sulfur atom, and n is an integer from 0 to 2.]

[0033] [Item 9] A method for producing a sulfur-containing siloxane, wherein the sulfur-containing siloxane is represented by formula (1).

[0034]

[0035] [In formula (1), R 1 ~R 8 is independently, each time it appears, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. R 1 ~R 8 optionally bond to each other to form a ring. X 1 ~X 3 is independently, each time it appears, an oxygen atom or a sulfur atom, and n is an integer from 0 to 2.]

[0036] The method for producing the sulfur-containing siloxane includes: (a) a step of synthesizing the sulfur-containing siloxane from a raw material siloxane; and (b) a distillation step of separating the sulfur-containing siloxane by distillation.

[0037] [Item 10] The method for producing a sulfur-containing siloxane according to Item 9, wherein in step (a), the raw material siloxane is reacted with a sulfurizing agent to synthesize the sulfur-containing siloxane.

[0038] [Item 11] The method for producing a sulfur-containing siloxane according to Item 9 or 10, wherein the raw material siloxane is represented by the following formula (4).

[0039]

[0040] [In formula (4), R 1 ~R 8 is independently, each time it appears, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. R 1 ~R 8 optionally bond to each other to form a ring. X1 to X 3 Each occurrence of X is independently an oxygen atom or a sulfur atom, Y is a hydrogen atom or a halogen atom, and n is an integer of 0 to 2.

[0041] [Item 12] A method for manufacturing a silicon-containing film, wherein a sulfur-containing siloxane represented by formula (1) is used.

[0042]

[0043] [In formula (1), R 1 to R 8 Each occurrence of R is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. R 1 to R 8 Optionally, they are bonded to each other to form a ring. X 1 to X 3 Each occurrence of X is independently an oxygen atom or a sulfur atom, and n is an integer of 0 to 2.

[0044] Advantages of the Invention

[0045] According to the present disclosure, by using a specific silicon-oxygen-sulfur compound having a sulfur atom as a silicon-containing film precursor, a uniform and high-quality film can be formed by the ALD method under higher temperature conditions. For example, by the method of the present disclosure, the obtained silicon film can exhibit good shrinkage rate and / or good etching rate. Therefore, according to the method of the present disclosure, uniform film formation with excellent film characteristics can be performed even under high temperature conditions, and thus high-performance semiconductor devices can be fabricated. Brief Description of the Drawings

[0046] Figure 1 The 1 H-NMR spectrum of 2,2,4,4,6,6,8,8-octamethyl-1,3,5-trioxa-7-thia-2,4,6,8-tetrasilacyclooctane obtained by the manufacturing method in Example 1 of the present disclosure.

[0047] Figure 2 Shows the relationship between the substrate temperature and the deposition rate in Example 2 of the present disclosure and Comparative Examples 1 to 3. Detailed Description of the Invention

[0048] <Sulfur-Containing Siloxane>

[0049] The sulfur-containing siloxane of the present disclosure has at least one sulfur atom and has a cyclic structure.

[0050] The sulfur-containing siloxane in the present disclosure is represented by the following formula (1).

[0051]

[0052] [In formula (1), R 1 ~R 8 is independently, each time it appears, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. R 1 ~R 8 optionally bond to each other to form a ring. X 1 ~X 3 is independently, each time it appears, an oxygen atom or a sulfur atom, and n is an integer from 0 to 2.]

[0053] [R 1 ~R 8

[0054] R 1 ~R 8 is independently, each time it appears, a hydrogen atom, an alkyl group having 1 to 5 (e.g., 1 to 3, 1 to 2, 1) carbon atoms (e.g., methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, pentyl), an alkenyl group having 2 to 5 (e.g., 2 to 4, 2 to 3, and 2) carbon atoms (e.g., vinyl or 2-propenyl), an alkynyl group having 2 to 5 (e.g., 2 to 4, 2 to 3, and 2) carbon atoms (e.g., ethynyl or propynyl), or an alkoxy group having 1 to 5 (e.g., 1 to 3, 1 to 2, and 1) carbon atoms (e.g., methoxy, ethoxy, propoxy).

[0055] R 1 ~R 8 can have an average carbon atom number of 0.5 or more, 1 or more, 2 or more, or 3 or more, preferably 1 or more. R 1 ~R 8 can have an average carbon atom number of 5 or less, 4 or less, 3 or less, 2 or less, or 1, preferably 3 or less, for example 2 or less.

[0056] R 1 ~R 8 can be linear, branched, or cyclic, preferably linear or branched, more preferably linear.

[0057] Here, R 1 ~R 8 can bond to each other to form a ring, or can not form a ring (in the case of forming a ring, it can form a ring at a position where one R 1 ~R 8 is bonded to, for example, the same silicon atom or an adjacent silicon atom as R 1 ~R 8 ). It should be noted that here, bonding can mean that R 1 ~R 8 ​Each has a bonding bond (for example, each R 1 ~R 8 produces a bonding bond by the detachment of a hydrogen atom) and bonds to each other.

[0058] R 1 ~R 8 At least one of (for example, 1 or more, 2 or more, 3 or more, 4 or more, or 5 or more) can be a hydrocarbon group or an alkoxy group (for example, a hydrocarbon group, especially an alkyl group). R 1 ~R 8 All can be other than a hydrogen atom. As the hydrocarbon group or alkoxy group (for example, a hydrocarbon group, especially an alkyl group), R 1 ~R 8 The number of can be 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more, preferably 50% or more, relative to the total number of R 1 ~R 8 . As the hydrocarbon group or alkoxy group (for example, a hydrocarbon group, especially an alkyl group), R 1 ~R 8 The number of can be 100% or less, 95% or less, 85% or less, 75% or less, or 65% or less, relative to the total number of R 1 ~R 8 . R 1 ~R 8 All can be a hydrocarbon group or an alkoxy group (for example, a hydrocarbon group, especially an alkyl group).

[0059] R 1 ~R 8 Are optionally the same or different, for example, can be the same. As a suitable example, there can be mentioned the case where R 1 ~R 8 Are all alkyl groups, especially methyl groups.

[0060] [X 1 ~X 3

[0061] X 1 ~X 3 When each appears, is independently an oxygen atom or a sulfur atom.

[0062] X 1 ~X 3 At least one of (for example, 1 or more, 2 or more, 3 or more, or 4) can be an oxygen atom. As the oxygen atom, X 1 ~X 3 The number of is relative to X 1 ~X 3 ​The total amount can be 20% or more, 40% or more, 60% or more, or 80% or more, preferably 40% or more. X which is an oxygen atom 1 ~X 3 The amount of 1 ~X 3 can be 100% or less, 70% or less, or 40% or less relative to the total amount of X 1 ~X 3 can all be oxygen atoms.

[0063] [n]

[0064] n is an integer from 0 to 2, being 0, 1, or 2, for example 0 or 1, 0 or 2, or 1 or 2, especially 1.

[0065] [Others]

[0066] The molecular weight of the sulfur-containing siloxane can be 200 or more, 250 or more, 300 or more, 350 or more, 400 or more, 450 or more, 500 or more, 550 or more, or 600 or more, preferably 300 or more. The molecular weight of the sulfur-containing siloxane can be 1000 or less, 900 or less, 800 or less, 700 or less, 600 or less, 500 or less, 400 or less, or 350 or less, preferably 400 or less.

[0067] The number of carbon atoms of the sulfur-containing siloxane can be 0 or more, 1 or more, 4 or more, 6 or more, 8 or more, 10 or more, 12 or more, 15 or more, or 20 or more, preferably 6 or more. The number of carbon atoms of the sulfur-containing siloxane can be 50 or less, 40 or less, 30 or less, 25 or less, 20 or less, 15 or less, 10 or less, preferably 20 or less.

[0068] When there are many Si—O structures in one molecule, in terms of forming a silicon oxide film, the constituent elements are similar to the film composition, so it is preferred from the viewpoint of film properties. On the other hand, although the detailed reasons are unclear, when there is a Si—S structure, ALD film formation under high-temperature conditions can be carried out. On the other hand, from the viewpoints of film formability and vapor pressure control, the molecular size is also important. The inventors of the present application repeatedly discussed in depth and found that a sulfur-containing siloxane having a moderate number of Si—O structures and a moderate molecular weight as specified above can achieve good effects.

[0069] [Examples of sulfur-containing siloxane]

[0070] As an example of the sulfur-containing siloxane, the compound represented by the formula (2) can be cited.

[0071]

[0072] [In formula (2), R 1 ~R 8 is independently, when each appears, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, and n is an integer of 0 to 2.]

[0073] In formula (2), regarding the details of R 1 ~R 8 and n, the description of the above formula (1) is incorporated by reference.

[0074] As specific examples of the sulfur-containing siloxanes in the present disclosure, the following can be cited: 2,2,4,4,6,6,8,8-octamethyl-1,3,5-trioxa-7-thia-2,4,6,8-tetrasilacyclooctane, 1,3-dioxo-5-thia-2,4,6-trisilacyclohexane, 2,2,4,4,6,6-hexamethyl-1,3-dioxo-5-thia-2,4,6-trisilacyclohexane, 2,2,4,4,6,6-hexaethyl-1,3-dioxo-5-thia-2,4,6-trisilacyclohexane, 2,2,4,4,6,6-hexavinyl-1,3-dioxo-5-thia-2,4,6-trisilacyclohexane, 2,2,4,4,6,6-hexapropyl-1,3-dioxo-5-thia-2,4,6-trisilacyclohexane, 2,2,4,4,6,6-hexaisopropyl-1,3-dioxo-5-thia-2,4,6-trisilacyclohexane, 2,2,4,4,6,6-hexabutyl-1,3-dioxo-5-thia-2,4,6-trisilacyclohexane, 1,3,5-trioxa-7-thia-2,4,6,8-tetrasilacyclooctane, 2,2,4,4,6,6,8,8-octaethyl-1,3,5-trioxa-7-thia-2,4,6,8-tetrasilacyclooctane, 2,2,4,4,6,6,8,8-octavinyl-1,3,5-trioxa-7-thia-2,4,6,8-tetrasilacyclooctane, 2,2,4,4,6,6,8,8-octapropyl-1,3,5-trioxa-7-thia-2,4,6,8-tetrasilacyclooctane, 2,2,4,4,6,6,8,8-octaisopropyl-1,3,5-trioxa-7-thia-2,4,6,8-tetrasilacyclooctane, 2,2,4,4,6,6,8,8-octabutyl-1,3,5-trioxa-7-thia-2,4,6,8-tetrasilacyclooctane, 1,3,5,7-tetraoxa-9-thia-2,4,6,8,10-pentasilacyclodecane, 2,2,4,4,6,6,8,8,10,10-decamethyl-1,3,5,7-tetraoxa-9-thia-2,4,6,8,10-pentasilacyclodecane, 2,2,4,4,6,6,8,8,10,10-decaethyl-1,3,5,7-tetraoxa-9-thia-2,4,6,8,10-pentasilacyclodecane, 2,2,4,4,6,6,8,8,10,10-decavinyl-1,3,5,7-tetraoxa-9-thia-2,4,6,8,10-pentasilacyclodecane, 2,2,4,4,6,6,8,8,10,10-decapropyl-1,3,5,7-tetraoxa-9-thia-2,4,6,8,10-pentasilacyclodecane, 2,2,4,4,6,6,8,8,10,10-decaisopropyl-1,3,5,7-tetraoxa-9-thia-2,4,6,8,10-pentasilacyclodecane, 2,2,4,4,6,6,8,8,10,10 - decabutyl - 1,3,5,7 - tetraoxa - 9 - thia - 2,4,6,8,10 - pentasilacyclodecane, etc.

[0075] <Method for Producing Sulfur - containing Siloxane>

[0076] The method for producing a sulfur - containing siloxane in the present disclosure may include the following production method, which includes: (a) a step of synthesizing a sulfur - containing siloxane from a raw material siloxane; and (b) a distillation step of isolating the sulfur - containing siloxane by distillation.

[0077] [Synthesis Step (a)]

[0078] In the synthesis step (a), it may include a step of reacting a raw material siloxane with a sulfurizing agent.

[0079] The raw material siloxane may be a compound represented by the following formula (4).

[0080]

[0081] [In formula (4), R 1 ~R 8 are each independently, when they appear, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. R 1 ~R 8 optionally bond to each other to form a ring. X 1 ~X 3 are each independently, when they appear, an oxygen atom or a sulfur atom. Y is a hydrogen atom or a halogen atom, and n is an integer from 0 to 2.]

[0082] In formula (4), regarding the details of R 1 ~R 8 and n, refer to the description of the above - mentioned formula (1).

[0083] Y is a hydrogen atom or a halogen atom. Examples of Y include: a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0084] The siloxane compound in which Y is a hydrogen atom can be used as it is in the synthesis step (a), or the synthesis step (a) can be carried out after substituting Y with a halogen using a halogenating agent. The halogenating agent can be a fluorinating agent, a chlorinating agent, a brominating agent, or an iodinating agent. Among them, chlorinating agents such as N - chlorosuccinimide and N - chloro - phthalimide are preferably used.

[0085] The molecular weight of the raw material siloxane can be 150 or more, 200 or more, 250 or more, 300 or more, 350 or more, 400 or more, 450 or more, 500 or more, or 550 or more, preferably 250 or more. The molecular weight of the raw material siloxane can be 1000 or less, 900 or less, 800 or less, 700 or less, 600 or less, 500 or less, 400 or less, 350 or less, or 300 or less, preferably 350 or less.

[0086] The vulcanizing agent is a sulfur compound that can replace Y in -SiY with sulfur. For example, sulfides such as lithium sulfide, sodium sulfide, and hydrogen sulfide can be used.

[0087] An example of the reaction formula of the raw material siloxane (4) and the vulcanizing agent is shown in the following formula (5).

[0088]

[0089] In step (a), the following methods can all be applied to this reaction: a method of initially dissolving the raw material siloxane (e.g., raw material siloxane (4)) in an organic solvent and adding the vulcanizing agent thereto; and a method of previously dissolving the vulcanizing agent in an organic solvent and adding the raw material siloxane (e.g., raw material siloxane (4)).

[0090] The usage amount of the vulcanizing agent is usually 0.2 to 3.0 moles, preferably 0.4 to 2.0 moles, relative to 1.0 mole of the raw material siloxane (e.g., raw material siloxane (4)).

[0091] The reaction can be carried out in the range of -20°C to 100°C, preferably in the range of -10°C to 60°C. The reaction time is usually in the range of 0.5 to 30 hours.

[0092] Solvents that can be used in this disclosure include, for example, hydrocarbons such as hexane, cyclohexane, heptane, nonane, and decane; halogenated hydrocarbons such as dichloroethane, dichloromethane, and chloroform; aromatic hydrocarbons such as benzene, toluene, xylene, chlorobenzene, and trichlorobenzene; ethers such as diethyl ether, tetrahydrofuran (THF), and ethylene glycol dimethyl ether, and mixtures thereof. Among them, ethers such as diethyl ether and tetrahydrofuran (THF) are preferred, and tetrahydrofuran (THF) is particularly preferably used. The usage amount of the solvent is usually 0.1 to 50 times the mass of the raw material siloxane compound.

[0093] To avoid hydrolysis of siloxane and sulfur-containing siloxane, it is desirable that the entire reaction system is carried out under anhydrous conditions, and the water in all the raw materials used is in the range of 0 to 5000 mass ppm, preferably 0 to 500 mass ppm, relative to the total mass of all the raw materials. In addition, it is desirable that the reaction apparatus uses a device dried by heating and drying and purging with an inert gas such as nitrogen or argon.

[0094] In step (a), when solids such as by - product salts are present in the reaction solution, filtration can be carried out as needed after the reaction ends. When carrying out filtration, in order to inhibit the decomposition of the sulfur - containing siloxane, it is desirable to carry out the filtration under a dried inert gas such as nitrogen or argon. The filtration temperature is not uniquely determined and can be applied in the range from 10 °C to the boiling point of the solvent used. Desirably, it is preferably carried out in the range from 20 °C to 65 °C.

[0095] [Distillation step (b)]

[0096] In step (b), the sulfur - containing siloxane is isolated by carrying out distillation, such as vacuum distillation. The sulfurizing agent and the organic solvent are easily removed, and the sulfur - containing siloxane can be purified to a sufficiently high purity.

[0097] <Method for manufacturing a silicon - containing film>

[0098] The sulfur - containing siloxane of the present disclosure can be used as an intermediate for a silicon - containing film to form a silicon - containing film on a substrate. The method for forming the silicon - containing film of the present disclosure can be chemical vapor deposition, particularly atomic layer deposition. More specifically, the method for forming the silicon - containing film of the present disclosure can be a chemical vapor deposition method (particularly atomic layer deposition method) including the following steps (c) to (f).

[0099] (c) A step of bringing a sulfur - containing siloxane composition containing the sulfur - containing siloxane represented by the following formula (1) into contact with a substrate to adsorb the sulfur - containing siloxane composition on the substrate.

[0100]

[0101] [In formula (1), R 1 ~R 8 are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms when each appears, R 1 ~R 8 optionally bond to each other to form a ring, X 1 ~X 3 are each independently an oxygen atom or a sulfur atom when each appears, and n is an integer from 0 to 2.]

[0102] (d) A step of purging the unadsorbed sulfur - containing siloxane composition and by - products.

[0103] (e) A step of injecting a reaction gas into the substrate on which the sulfur - containing siloxane composition is adsorbed, whereby the sulfur - containing siloxane decomposes to form an atomic layer.

[0104] (f) A step of purging the unreacted reaction gas and by - products.

[0105] The temperature of the substrate can be carried out at 100 - 800 °C, preferably 100 - 750 °C. From the perspective of the obtained film properties, the temperature of the substrate can be 200 °C or higher, 300 °C or higher, 400 °C or higher, 500 °C or higher, 600 °C or higher, or 700 °C or higher. For example, it is 250 °C or higher, preferably 300 °C or higher, 400 °C or higher, or 500 °C or higher. It should be noted that the film formation temperature can be the temperature of at least one of the processes (c) - (f). For example, it is the temperature of the substrate when contacting with the sulfur-containing siloxane composition in process (c). The silicon-containing film obtained from the sulfur-containing siloxane of the present disclosure is stable even at high temperatures, and the sulfur-containing siloxane of the present disclosure can be preferably used even in the manufacturing method of a silicon-containing film using a high-temperature substrate temperature.

[0106] In processes (c) and (e), the pressure when injecting gas is 0.05 - 100 Torr, preferably 0.05 - 50 Torr. The sulfur-containing siloxane composition can contain inert gases such as nitrogen and argon as carrier gases.

[0107] In process (e), as the reaction gas, when forming a silicon oxide film having a Si - O bond, one or more gases selected from oxygen, ozone, and nitric oxide can be used. When forming a silicon nitride film having a Si - N bond, one or more gases selected from nitrogen, ammonia, nitrous oxide, nitric oxide, and nitrogen dioxide can be used.

[0108] Ideally, the formation of the silicon-containing film is carried out after replacement with an inert gas such as nitrogen or argon. That is, it is preferably carried out after replacing the inside of the reaction system with an inert gas in the above process (c).

[0109] The sulfur-containing siloxane in the present disclosure is preferably used for the manufacture of silicon-containing films (such as silicon oxide films and silicon nitride films) using chemical vapor deposition methods (especially atomic layer deposition methods). In the manufacturing method of the silicon-containing film in the present disclosure, the lower limit of its ALD window can be 300 °C, preferably 350 °C. In addition, in the manufacturing method of the silicon-containing film in the present disclosure, the upper limit of the ALD window can be 800 °C, preferably 750 °C. Here, the ALD window generally refers to the temperature range between the vaporization temperature of the silicon-containing film precursor compound and the thermal decomposition temperature of the silicon-containing film precursor compound. In the present specification, the ALD window can be defined as the temperature range from the point where the deposition rate becomes maximum to the point where it becomes minimum when the film formation temperature is set as the horizontal axis and the deposition rate is set as the vertical axis.

[0110] Above, the embodiments have been described, but it should be understood that various changes in the solutions and details can be made without departing from the gist and scope of the claims.

[0111] Examples

[0112] Hereinafter, examples will be listed to explain the present disclosure in detail, but the present disclosure is not limited to these examples.

[0113] [Example 1: Synthesis of 2,2,4,4,6,6,8,8 - octamethyl - 1,3,5 - trioxa - 7 - thia - 2,4,6,8 - tetrasilacyclooctane]

[0114] After nitrogen replacement, 1.98 g (0.043 mol) of lithium sulfide and 317 g of tetrahydrofuran were added to a 500 mL flask equipped with a thermometer, a condenser, and a motor stirrer. While stirring at room temperature, 10.9 g (0.031 mol) of 1,7 - dichlorooctamethyltetrasiloxane was slowly added dropwise. After the addition, the mixture was stirred for 6 hours while maintaining the temperature at 20 - 26 °C. Then, under reduced pressure distillation at an internal temperature of 50 - 60 °C, tetrahydrofuran was removed. Then, in a glove box purged with nitrogen, solid substances mainly composed of by - product lithium chloride were removed by vacuum filtration, and a solution containing 2,2,4,4,6,6,8,8 - octamethyl - 1,3,5 - trioxa - 7 - thia - 2,4,6,8 - tetrasilacyclooctane was obtained. Then, under reduced pressure distillation at an internal temperature of 68 °C and 1.9 Torr, 2,2,4,4,6,6,8,8 - octamethyl - 1,3,5 - trioxa - 7 - thia - 2,4,6,8 - tetrasilacyclooctane was obtained in high purity.

[0115] By GC analysis after distillation, it was confirmed that 5.7 g (yield 58%) of 2,2,4,4,6,6,8,8 - octamethyl - 1,3,5 - trioxa - 7 - thia - 2,4,6,8 - tetrasilacyclooctane was obtained with a purity of 98.3% by area. The obtained 2,2,4,4,6,6,8,8 - octamethyl - 1,3,5 - trioxa - 7 - thia - 2,4,6,8 - tetrasilacyclooctane was identified by 1 1H - NMR and GC - MS. 1 The assignment of 1H - NMR is as follows. 1 The 1H - NMR spectrum is as Figure 1 shown.

[0116] 1 1H - NMR (400 MHz, CDCl3): δ0.12 (s, 12H, CH 3 -Si]), δ0.43 (s, 12H, CH 3 -SiS).

[0117] According to the above 1 1H - NMR and GC - MS results, the obtained sulfur - containing siloxane was identified as 2,2,4,4,6,6,8,8 - octamethyl - 1,3,5 - trioxa - 7 - thia - 2,4,6,8 - tetrasilacyclooctane of the following formula.

[0118]

[0119] [Example 2: Formation of a silicon-containing film using 2,2,4,4,6,6,8,8-octamethyl-1,3,5-trioxa-7-thia-2,4,6,8-tetrasilacyclooctane]

[0120] A silicon substrate was placed in a vacuum apparatus and heated to a specified temperature of 500 to 750 °C. A siloxane composition containing 2,2,4,4,6,6,8,8-octamethyl-1,3,5-trioxa-7-thia-2,4,6,8-tetrasilacyclooctane obtained in Example 1 and a carrier gas was injected at a pressure of 0.05 to 100 Torr so as to be adsorbed on the heated silicon substrate. Subsequently, argon gas was introduced to purge the unadsorbed sulfur-containing siloxane composition and by-products in the apparatus. Then, ozone as a reaction gas was injected at a pressure of 0.05 to 100 Torr, and an atomic layer of silicon oxide derived from 2,2,4,4,6,6,8,8-octamethyl-1,3,5-trioxa-7-thia-2,4,6,8-tetrasilacyclooctane was deposited on the substrate. Subsequently, argon gas was introduced to purge the unreacted ozone and by-products. The above cycle was repeated to obtain a silicon oxide film.

[0121] [Comparative Example 1: Formation of a silicon-containing film using bis(diethylamino)silane]

[0122] A silicon substrate was placed in a vacuum apparatus and heated to a specified temperature of 100 to 750 °C. An aminosilane composition containing bis(diethylamino)silane and a carrier gas was injected at a pressure of 0.05 to 100 Torr so as to be adsorbed on the heated silicon substrate. Subsequently, argon gas was introduced to purge the unadsorbed aminosilane composition and by-products in the apparatus. Then, ozone as a reaction gas was injected at a pressure of 0.05 to 100 Torr, and an atomic layer of silicon oxide derived from bis(diethylamino)silane was deposited on the substrate. Subsequently, argon gas was introduced to purge the unreacted ozone gas and by-products. The above cycle was repeated to obtain a silicon oxide film.

[0123] [Comparative Example 2: Formation of a silicon-containing film using 2-dimethylamino-2,4,6,8-tetramethylcyclotetrasiloxane]

[0124] A silicon substrate is set inside a vacuum device and heated to a specified temperature of 100 to 750 °C. A siloxane composition containing 2-dimethylamino-2,4,6,8-tetramethylcyclotetrasiloxane and a carrier gas is injected at a pressure of 0.05 to 100 Torr so as to be adsorbed onto the heated silicon substrate. Next, argon gas is introduced, whereby the unadsorbed amino siloxane composition and by-products are purged inside the device. Then, ozone as a reaction gas is injected at a pressure of 0.05 to 100 Torr, and an atomic layer of silicon oxide derived from 2-dimethylamino-2,4,6,8-tetramethylcyclotetrasiloxane is formed by deposition on the substrate. Next, argon gas is introduced, whereby the unreacted ozone gas and by-products are purged. The above cycle is repeated to obtain a silicon oxide film.

[0125] [Comparative Example 3: Formation of a silicon-containing film using 2,4,6,8-tetramethylcyclotetrasiloxane]

[0126] A silicon substrate is set inside a vacuum device and heated to a specified temperature of 200 to 750 °C. A siloxane composition containing 2,4,6,8-tetramethylcyclotetrasiloxane and a carrier gas is injected at a pressure of 0.05 to 100 Torr so as to be adsorbed onto the heated silicon substrate. Next, argon gas is introduced, whereby the unadsorbed siloxane composition and by-products are purged inside the device. Then, ozone as a reaction gas is injected at a pressure of 0.05 to 100 Torr, and an atomic layer of silicon oxide derived from 2,4,6,8-tetramethylcyclotetrasiloxane is formed by deposition on the substrate. Next, argon gas is introduced, whereby the unreacted ozone gas and by-products are purged. The above cycle is repeated to obtain a silicon oxide film.

[0127] The specific vapor deposition methods are shown in Table 1 below. Figure 2 The relationship between the substrate temperature and the deposition rate is shown. In the measurement of each of the Figure 2 marks, the siloxane supply time at which the deposition rate becomes the maximum is selected. Table 2 shows the deposition rates when the cycle is repeated 50 times at a substrate temperature of 725 °C, which is the highest temperature as the ALD window, and 750 °C outside the ALD window in Example 2. Here, the ALD window means Figure 2The temperature range from the point where the deposition rate becomes maximum to the point where it becomes minimum. In addition, Table 3 summarizes the temperature ranges of the ALD windows for Example 1 and Comparative Examples 1 and 2. It should be noted that the thickness of the layer was measured using an ellipsometer. Table 4 shows the shrinkage rate after film formation near the upper limit of the ALD window (700 °C for the example and 550 °C for Comparative Example 1) and annealing at 800 °C for 30 minutes. Table 5 shows the etching rate when immersed in 0.5% hydrofluoric acid for 60 seconds after film formation near the upper limit of the ALD window (700 °C for the example and 500 °C for Comparative Example 1). The etching rate was calculated by measuring the film thickness before and after immersion in 0.5% hydrofluoric acid using an ellipsometer, calculating the reduction in film thickness, and dividing it by the immersion time.

[0128] [Table 1]

[0129] Raw material supply 3 to 12 seconds Supply with Ar Ar purge ① 45 seconds 50 - 170 sccm Ozone supply 6 seconds 100 sccm Ar purge ② 45 seconds 50 - 170 sccm

[0130] [Table 2]

[0131]

[0132] [Table 3]

[0133]

[0134] [Table 4]

[0135]

[0136] [Table 5]

[0137]

[0138] As shown in Table 2, in Example 2, in order to form an atomic layer of silicon oxide derived from 2,2,4,4,6,6,8,8 - octamethyl - 1,3,5 - trioxa - 7 - thia - 2,4,6,8 - tetrasilacyclooctane compound, the supply time of the 2,2,4,4,6,6,8,8 - octamethyl - 1,3,5 - trioxa - 7 - thia - 2,4,6,8 - tetrasilacyclooctane composition was studied. It was confirmed that the deposition rate became maximum at 6 seconds or more at a substrate temperature of 725 °C, and it was ALD film formation.

[0139] As shown in Table 3 and Figure 2 it was confirmed that the temperature range (ALD window) in which 2,2,4,4,6,6,8,8 - octamethyl - 1,3,5 - trioxa - 7 - thia - 2,4,6,8 - tetrasilacyclooctane can perform ALD film formation is located on the higher temperature side compared to bis(diethylamino)silane and 2 - dimethylamino - 2,4,6,8 - tetramethylcyclotetrasiloxane.

[0140] As shown in Tables 4 and 5, it was confirmed that 2,2,4,4,6,6,8,8 - octamethyl - 1,3,5 - trioxa - 7 - thia - 2,4,6,8 - tetrasilacyclooctane can form a high - quality film with a low shrinkage rate and etching rate in ALD film formation compared to bis(diethylamino)silane.

[0141] Industrial applicability

[0142] If the method described in the present disclosure is used, even on a semiconductor substrate or nanowire having a structure with a high aspect ratio, an extremely thin silicon oxide film or the like without atomic defects can be formed. In particular, the sulfur - containing siloxane of the present disclosure is useful in the atomic deposition method for film formation at high temperatures.

Claims

1. A silicon-containing film precursor, wherein, it contains a sulfur-containing siloxane represented by formula (1), in formula (1), R 1 ~R 8 Each, when it appears, independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, R 1 ~R 8 Optionally, they are bonded to each other to form a ring, X 1 ~X 3 each independently represents an oxygen atom or a sulfur atom when it appears respectively, n is an integer from 0 to 2.

2. The silicon-containing film precursor according to claim 1, wherein, X 1 ~X 3 is an oxygen atom.

3. The silicon-containing film precursor according to claim 1 or 2, wherein, the sulfur-containing siloxane is represented by formula (2), in formula (2), R 1 ~R 8 Each, when it appears, is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. n is an integer from 0 to 2.

4. The silicon-containing film precursor according to any one of claims 1 to 3, wherein, R 1 ~R 8 Each, when it appears, is independently an alkyl group having 1 to 5 carbon atoms.

5. The silicon-containing film precursor according to any one of claims 1 to 4, wherein, the sulfur-containing siloxane is 2,2,4,4,6,6,8,8 - octamethyl - 1,3,5 - trioxa - 7 - thia - 2,4,6,8 - tetrasilacyclooctane represented by formula (3), 6. The silicon-containing film precursor according to any one of claims 1 to 5, wherein, the silicon-containing film is formed by chemical vapor deposition.

7. The silicon-containing film precursor according to any one of claims 1 to 6, wherein, the silicon-containing film is formed by atomic layer deposition.

8. A composition for forming a silicon-containing film, wherein, it contains a sulfur-containing siloxane represented by formula (1), in formula (1), R 1 ~R 8 Each, when it appears, is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, R 1 ~R 8 Optionally, they are bonded to each other to form a ring, X 1 ~X 3 each independently represents an oxygen atom or a sulfur atom when it appears n is an integer from 0 to 2.

9. A method for manufacturing a sulfur-containing siloxane, wherein, the sulfur-containing siloxane is represented by formula (1), in formula (1), R 1 ~R 8 Each, when it appears, is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, R 1 ~R 8 Optionally, they are bonded to each other to form a ring, X 1 ~X 3 Each, when it appears, is independently an oxygen atom or a sulfur atom, n is an integer from 0 to 2, the method for manufacturing the sulfur-containing siloxane includes: a: a step of synthesizing the sulfur-containing siloxane from a raw material siloxane; and b: a distillation step of separating the sulfur-containing siloxane by distillation.

10. The method for manufacturing a sulfur-containing siloxane according to claim 9, wherein, in step a, the raw material siloxane is reacted with a sulfurizing agent to synthesize the sulfur-containing siloxane.

11. The method for manufacturing a sulfur-containing siloxane according to claim 9 or 10, wherein, the raw material siloxane is represented by the following formula (4), in formula (4), R 1 ~R 8 Each, when it appears, is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, R 1 ~R 8 Optionally, they are bonded to each other to form a ring, X 1 ~X 3 Each, when it appears, is independently an oxygen atom or a sulfur atom, Y is a hydrogen atom or a halogen atom, n is an integer from 0 to 2.

12. A method for manufacturing a silicon-containing film, wherein, a sulfur-containing siloxane represented by formula (1) is used, in formula (1), R 1 ~R 8 each independently represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms, R 1 ~R 8 optionally bonding to each other to form a ring X 1 ~X 3 each independently represents an oxygen atom or a sulfur atom when it appears respectively, n is an integer from 0 to 2.

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