Method for producing silicon-containing film and method for producing electronic device

Abstract

Provided is a method for producing a silicon-containing film. The production method according to the present invention may be used together with nano-technology processes in order to produce applications for semiconductor devices and display devices. For example, the method can produce liquid crystal, quantum dots, OLED displays formed on substrates, or the like, which can be controlled with semiconductors. Preferred performance of the production method according to the present invention may be supported by at least one of the properties of high-performance materials and advanced materials. A method for producing a silicon-containing film, comprising the following steps (A) and (B): • (A) applying a composition comprising polysilazane above a substrate to form a film; and • (B) irradiating plasma to the film under an atmosphere that comprises gas (G) comprising a hydrogen atom and an oxygen atom.

Description

Foreignfiling text P25-188 20260309- 1 -DESCRIPTIONTITLE OF INVENTION:METHOD FOR PRODUCING SILICON-CONTAINING FILM AND METHOD FOR 5 PRODUCING ELECTRONIC DEVICETECHNICAL FIELD

[0001] The present invention relates to a method for producing a silicon- containing film and a method for producing an electronic device.BACKGROUND ART

[0002] An electronic device, particularly a semiconductor device, is made up of thin films such as a semiconductor film, an insulation film, and a conductive film. The silicon-containing film is used as a semiconductor film, as an etching mask 15 when an insulation film is processed, and as a sacrificial film when a metal gate or the like is produced.

[0003] NPL 1 describes the conversion of a precursor layer of polydimethylsiloxane and polysilazane into a thin oxide film by low-temperature atmospheric pressure plasma. NPL 2 describes the use of a polysilazane precursor 20 for forming an oxidized insulation film.CITATION LIST NON PATENT LITERATURE

[0004] [NPL 1] M. Rudolph, et al., “Low-temperature atmospheric pressure plasma conversion of polydimethylsiloxane and polysilazane precursor layers to oxide thin films”, Plasma Processes Polym. 2023; 20: e2200229.[NPL 2] Y. Urabe, et al., “Polysilazane Precursor Used for Formation of Oxidized Insulator”, MRS Online Proceedings Library 1066, 10660502 (2007)30 SUMMARY OF INVENTIONTECHNICAL PROBLEMForeignfiling text P25-188 20260309- 2 -

[0005] The inventors have considered that there are still one or more problems for which improvement is still required in the production of silicon-containing films. Examples of the problems include the following:to provide a method for producing a silicon-containing film which does not 5 require heating; to provide a method for producing a silicon-containing film that can form a film for a sufficiently short time; to provide a method for producing a silicon- containing film that can form a film at a sufficiently low temperature; to provide a method for producing a silicon-containing film that can form a film at room temperature; to provide a method for producing a silicon-containing film with a sufficient thickness; to provide a method for producing a silicon-containing film that is sufficiently oxidized; to provide a method for producing a silicon-containing film with a sufficiently low wet etching rate; to provide a method for producing a silicon- containing film with sufficiently small residual stress; to provide a method for producing a silicon-containing film with suppressed crack occurrence; to provide a 15 method for producing a silicon-containing film with suppressed film shrinkage; to provide a method for producing a silicon-containing film with sufficient withstand voltage; to provide a method for producing a silicon-containing film with sufficient heat resistance; to provide a method for producing a silicon-containing film with suppressed void occurrence; to provide a method for producing a silicon-containing 20 film with sufficient insulation properties; and to provide a method for producing a silicon-containing film with sufficient yield.

[0006] The present invention has been made based on the technical background as described above, and provides a method for producing a silicon-containing film and a method for producing an electronic device.SOLUTION TO PROBLEM

[0007] A method for producing a silicon-containing film according to one embodiment comprises the following steps (A) and (B):(A) applying a composition comprising polysilazane (hereafter sometimes 30 referred to as a “composition”) above a substrate to form a film; and(B) irradiating plasma to the film under an atmosphere that comprises gas (G) comprising a hydrogen atom and an oxygen atom.Foreignfiling text P25-188 20260309- 3 -

[0008] A method for producing an electronic device according to one embodiment comprises the method for producing the silicon-containing film described above.ADVANTAGEOUS EFFECTS OF INVENTION5

[0009] According to the present invention, it is possible to desire one or more of the following effects:a silicon-containing film can be formed without heating; time required to form a silicon-containing film is sufficiently short; the temperature upon formation of a silicon-containing film is sufficiently low; a silicon-containing film can be formed at room temperature; a silicon-containing film is sufficiently thick; a silicon-containing film is sufficiently oxidized; the wet etching rate of a silicon-containing film is sufficiently low; the residual stress in a silicon-containing film is sufficiently small; the occurrence of cracks in a silicon-containing film is suppressed; film shrinkage of a silicon-containing film is suppressed; the withstand voltage of a silicon-containing 15 film is sufficient; the heat resistance of a silicon-containing film is sufficient; the occurrence of voids in a silicon-containing film is suppressed; the insulation properties of a silicon-containing film are sufficient; and the yield of a silicon- containing film is sufficient.

[0010] The foregoing description should not be considered to disclose all20 embodiments of the present invention and all advantages relating to the present invention.BRIEF DESCRIPTION OF DRAWINGS

[0011] [Fig. 1]Fig. 1 is an FT-IR spectrum showing peaks of the silicon-containing films of Example 1, Comparative Example 1, and Reference Example 1.[Fig. 2]Fig. 2 is an FT-IR spectrum showing peaks of the silicon-containing films of Examples 1, 2, and 3.30 [Fig. 3]Fig. 3 is an FT-IR spectrum showing peaks of the silicon-containing films of Examples 1 and 4.Foreignfiling text P25-188 20260309- 4 -DESCRIPTION OF EMBODIMENTS

[0012] Embodiments of the present invention will be described below. However, the present invention is not limited only to these embodiments and may be variously 5 modified within the spirit and scope of the present invention.

[0013] DefinitionsIn the present disclosure, unless specifically limited otherwise, the definitions and examples described in this paragraph shall apply to terms and symbols.A singular form includes the plural form thereof and the term “a” or “the” means “at least one”. An element of a certain concept can be expressed by a plurality of types, and when the amount (e.g., mass% or mol%) thereof is described, the amount thereof means a sum of the plurality of types thereof.The term “and / or” includes all combinations of elements, and also includes use of either one of the elements.15 When a numerical range is indicated using “to” or both endpoints are included in the range, and the units are common. For example, 5 to 25 mol% means 5 mol% or more and 25 mol% or less.Notations such as “Cx-y”, “Cx to Cy”, “Cx” mean the number of carbon atoms in a molecule or substituent. For example, “C1-6 alkyl” means an alkyl chain having 1 or 20 more and 6 or less carbon atoms (such as methyl, ethyl, propyl, butyl, pentyl, or hexyl).The degree Celsius is used as the unit for temperatures. For example, 20 degrees (20°C) means 20 degrees Celsius.An optional component means a compound itself having the indicated function. For example, a base generator refers to a compound itself that generates a base. There may also be an embodiment in which the compound is dissolved or dispersed in a solvent and added to the composition.Polysilazane means a polymer having a basic skeleton -[N-Si]- in which silicon atoms and nitrogen atoms are alternately arranged. Polysilazanes also encompass 30 polymers that include a siloxane bond (Si-O), a silicon-carbon bond (Si-C), or a combination thereof in the molecule, in addition to the above basic skeleton. A polymer in which a part of the basic skeleton of polysilazane is substituted byForeignfiling text P25-188 20260309- 5 -siloxane bonds is also called polysiloxazane. A polymer in which a part of the basic skeleton of polysilazane is replaced with a silicon-carbon bond is also called polycarbosilazane.

[0014] <Method for Producing Silicon-Containing Film>5 The method for producing a silicon-containing film of the present invention (hereinafter, sometimes referred to as “the method of the present invention”) comprises or consists of the following steps (A) and (B):(A) applying a composition comprising polysilazane above a substrate to form a film; and10 (B) irradiating plasma to the film under an atmosphere that comprises gas (G) comprising a hydrogen atom and an oxygen atom.

[0015] [Step A](Composition Comprising Polysilazane)- PolysilazaneThe polysilazane preferably comprises a unit A represented by formula (1). [C1]- ZHS'i1-N- \j- (1)\ R2R.3 / R1and R2are each independently a single bond, H, C1-10 alkyl, C2-10 alkenyl, C6-12 aryl, or a linking group represented by any one of formulas (a), (b), and (c); 20 preferably H, linear C1-10 alkyl, branched C3-10 alkyl, cyclic C3-10 alkyl, linear C2-10 alkenyl, branched C3-10 alkenyl, cyclic C3-10 alkenyl, C6-12 aryl, or a linking group represented by any one of formulas (a), (b), and (c); more preferably H, linear C1-5 alkyl, or a linking group represented by any one of formulas (a), (b), and (c); still more preferably H, methyl, ethyl, n-propyl, isopropyl, or a linking group represented 25 by any one of formulas (a), (b), and (c); and even more preferably H, methyl, or a linking group represented by formula (b).One or more non-adjacent -CH2- groups in R1and R2may each independently be replaced with -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, or -C=C- Preferably, none of -CH2- in R1and R2is replaced with any group.Foreignfiling text P25-188 20260309- 6 -R1and R2are each independently, when being a single bond, bonded to N included in another unit represented by formula (1).R3is a single bond, H, C1-10 alkyl, C2-10 alkenyl, or C6-12 aryl; preferably H, linear C1-10 alkyl, branched C3-10 alkyl, cyclic C3-10 alkyl, linear C2-10 alkenyl,5 branched C3-10 alkenyl, cyclic C3-10 alkenyl, or C6-12 aryl; more preferably H or linear C1-5 alkyl; and still more preferably H, methyl, ethyl, n-propyl, or isopropyl.One or more non-adjacent -CH2- groups in R3may be replaced with -O-, -S-, - CO-, -CO-O-, -O-CO-, -O-CO-O-, or -C=C-. Preferably, none of -CH2- in R3is not replaced with any group.10 R3is, when being a single bond, bonded to Si contained in another unit represented by formula (1).[C2](Ra)3-na_|_a gj -( R^^2-nbl ( Rb2)2-nb2I I (b)t-qM2q( RCll I DC2\\ J / 3-ncl / 3-nc2— (Lcl)— -Si - 0 - Si (-Lc2)— -Ra, Rc1, and Rc2are each independently H, C1-6 alkyl, C2-6 alkenyl, or C6-12 aryl; preferably H, linear C1-6 alkyl, branched C3-6 alkyl, cyclic C3-6 alkyl, linear C2-6 alkenyl, branched C3-6 alkenyl, cyclic C3-6 alkenyl, or C6-12 aryl; more preferably H or linear C1-5 alkyl; and still more preferably H, methyl, ethyl, n-propyl, or isopropyl.Rb1and Rb2are each independently H, C1-6 alkyl, C2-6 alkenyl, or C6-12 aryl; preferably H, linear C1-6 alkyl, branched C3-6 alkyl, cyclic C3-6 alkyl, linear C2-6 20 alkenyl, branched C3-6 alkenyl, cyclic C3-6 alkenyl, or C6-12 aryl; more preferably H or linear C2-6 alkyl; and still more preferably H or vinyl.La, Lb1, Lb2, Lc1, and Lc2are each independently C1-8 alkylene, or Ce-14 arylene; preferably, linear C1-8 alkylene, branched C3-8 alkylene, or cyclic C3-8 alkylene, or Ce-Foreignfiling_text_P25-188_20260309- 7 -14 arylene; more preferably linear C1-5 alkylene; still more preferably methylene, ethylene, or linear propylene; and even more preferably ethylene.One or more non-adjacent -CH2- groups in La, Lb1, Lb2, Lc1, and Lc2may each independently be replaced with -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, - 5 CH=CH-, or -C=C- Preferably, none of -CH2- in La, Lb1, Lb2, Lc1, and Lc2are replaced with any group.na is 1 to 3, preferably 1.nb1 and nb2 are each independently 1 to 2, preferably 2.nc1 and nc2 are each independently 1 to 3, preferably 1.10 p and q are each independently 1 to 3, preferably 1.Among the bonds in the linking groups of any one of formulas (a), (b), and (c), a bond which is not bonded to Si contained in a unit represented by formula (1) is bonded to Si contained in another unit represented by formula (1).

[0016] Specific examples of the linking group represented by formula (a) include 15 the following.[C3]Foreignfiling_text_P25-188_20260309- 8 -CH, C2H5CH. HI H, I Hi Hi H, H, I H, H — c‘-c -Si— c‘-c‘- — C^-(f-Si— C -C C-H= CH- -3i “CH, CH, CH, CH, H, H, H2| H, H2H2— c -c — C —Si — c — c *c —CH, i “ CH, l " CH,CH3C2H3I-CH - CH2—Si — CH2— CH — CH2— CH2~ Si — CH2— CH2—CH3C2H3CH3C6H5-CH2-CH2-Si-CH2-CH2- -CH2- CH2~Si~CH2-CH2- CH2CH2CH2CH211CH, C3H5 l — CH2— CH2— CH2— Si— CH2— CH2— CH2~ — CH2— CH2— CH2— Si — CH2— CH2— CH2—CH3C3H5CH3C6H5I-CH2-CH - CH -Si-CH2-CH,- CH - - CH,-CH - CH - Si - CH2- CH2- CH2- CH2CH2CH2CH2CH2CH2IForeignfiling_text_P25-188_20260309- 9 -

[0017] Specific examples of the linking group represented by formula (b) include the following.[C4]CH3 x XCH2 X XCH2-CH2- Si Si -CH2“CHfXCH2^XCH2-CH2-Hx XCH2--CH2-- Hx XCH2^XCH2— CH2- Si Si ^Si Si -CH2~CHfXCH2X >CH2-CH2“- -CH2~CHfXCH2^XH CH2-CH2^ZCH2 X / CH=CH2CH3X XCH2>. XXH2-CH2- Si Si Si Six^CH / XXCH2-CH2^ -CH2-CH2X XCH2X XCH3CH2=CH 5

[0018] Specific examples of the linking group represented by formula (c) include the following.[C5]H2H2<rH3 PS H2C—C — Si — O-Si — C—C—C CH IH2C IH2 3CH3I I CH2CH2-CH2-CH2- Si - O— Si -CH2~CH2“CH3CH3

[0019] A detailed explanation will be given of how to read formula (1 ) with10 reference to an example of a substructure of the following polysilazane.[C6]Foreignfiling_text_P25-188_20260309- 10 -H2•SkHN' NH(A)H2Si SiHH2HH .Si- Qi ! ~Qi N Si— NH2H H2i I H H2HCH2CH2H5C2- Si — C2H6(B)CH2CH2H2H H i . ’*HSi — N — Si — N- — Si — N — "Si — N —H2H H I HNHSiH2

[0020] For the structure inside the broken line frame (A), in formula (1 ), R1can be read as H, and R2and R3can be read as single bonds. In this formula, R2is a single bond bonded to N contained in another unit represented by formula (1), and 5 R3is a single bond bonded to Si contained in another unit represented by formula (1).

[0021] For the structure inside the broken line frame (B), in formula (1 ), R1can be read as a single bond, R2can be read as a linking group represented by formula (a), and R3can be read as H. In this formula, R1is a single bond bonded to N 10 contained in another unit represented by formula (1 ).In formula (a), Racan be read as C2 alkyl, Lacan be read as C2 alkylene, and na can be read as 1. In this formula, the bond at the lowermost portion of the structure in the broken line frame (B) corresponds to a bond that is not bonded to Si contained in the unit represented by formula (1) among bonds of linking groups 15 represented by formula (a). Said bond is bonded to Si contained in another unit represented by formula (1).Foreignfiling text P25-188 20260309- 11 -

[0022] Polysilazane may comprise only a single type of unit A represented by formula (1 ), or two or more types thereof. When a plurality of Raare included in one unit, the Ramay be only a single type or two or more types. It is preferable that all Raare the same in one unit. The same applies to Rb1, Rb2, Rc1, and Rc2.

[0023] The polysilazane is preferably a polyperhydropolysilazane (PHPS). PHPS is a polysilazane consisting only of Si, N, and H. In PHPS, all elements bonded to Si or N, with the exception of Si-N bonds, are H. PHPS is substantially free of, preferably free of, any other element, such as carbon or oxygen. The PHPS may have a chain structure, a cyclic structure, or a crosslinked structure.It is believed that PHPS, as the polysilazane, enables more uniform application of the composition above a substrate and improves the heat resistance of the silicon-containing film.

[0024] In an embodiment, the polysilazane further comprises a unit B represented by formula (2):[C7]whereinR4is H, C1-10 alkyl, C2-10 alkenyl, or C6-12 aryl; preferably H, linear C1-10 alkyl, branched C3-10 alkyl, cyclic C3-10 alkyl, linear C2-10 alkenyl, branched C3-10 alkenyl, cyclic C3-10 alkenyl, or C6-12 aryl; and more preferably H or linear C1-5 alkyl; and still more preferably H, methyl, ethyl, n-propyl, or isopropyl.One or more non-adjacent -CH2- groups in R4may each independently be replaced with -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, or -C=C-. Preferably, none of -CH2- in R4is not replaced with any group.One or more H atoms in R4may be replaced with -NH2, -N=C=O, or OH.Preferably, none of H in R4is not replaced with any group.n1 is 2, 3, or 4, preferably 3 or 4.n2 is 4 - n1.Foreignfiling_text_P25-188_20260309- 12 -

[0025] The polysilazane may comprise another unit (hereinafter referred to as other units) than the units A and B.Given that the total number of the units A and B is taken as OAB, and the total number of the units in polysilazane is taken as ntotai, nAB / ntotai is preferably 80% or 5 more, more preferably 90% or more, and still more preferably 95% or more.An embodiment in which nAB / ntotai is 100%, that is, polysilazane is free of any other units is also a preferred embodiment of the present invention.It should be noted that the “unit” herein shall not include end groups.

[0026] The meaning of Oo.s in formula (2) will be described. An example of the 10 substructure of polysilazane comprising the units A and B is illustrated below.[C8]For convenience, the expression Oo.s is used in the above substructure in order to express the structures within two broken line frames, such as the following 15 formula (2-1). Formula (2-1) is a unit B, in which n1 is 4, and n2 is 0 in formula (2).[C9]Foreignfiling text P25-188 20260309

[0027] As shown in the substructure above, when the polysilazane comprises a unit B, the structure thereof may include an -Si-O-Si- bond. In that case, it is not appropriate to express a structure including Si-0 as a unit. For this reason, the expression O0.5 is used to express the unit B for convenience.

[0028] The polysilazane may comprise only a single type of unit represented by formula (2) or two or more types thereof.

[0029] It is preferable that the polysilazane comprises at least one end group represented by formula (3), and it is more preferable that all end groups of the polysilazane are represented by formula (3).-SiR31R32R33(3)R31, R32, and R33are each independently H, OH, C1-20 alkyl, C2-20 alkenyl, or Ce-20 aryl; preferably H, OH, linear C1-20 alkyl, branched C3-20 alkyl, cyclic C3-20 alkyl, linear C2-20 alkenyl, branched C3-20 alkenyl, cyclic C3-20 alkenyl, or C6-20 aryl; more preferably H, OH, linear C1-15 alkyl, or branched C3-15 alkyl; and still more preferably H, OH, linear C1-10 alkyl, or branched C3-10 alkyl; and even more preferably H, OH, or methyl.One or more non-adjacent -CH2- groups in R31, R32, and R33may each independently be replaced with -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, or -C=C- Preferably, none of -CH2- in R31, R32, and R33are replaced with any group.One or more H atoms in R31, R32, and R33may each independently be replaced with -OH, -COOH, or -SO2H. Preferably, none of H in R31, R32, and R33are replaced with any group.

[0030] It is believed that polysilazane comprising the unit B shortens the time of plasma irradiation required for forming a silicon-containing film.Foreignfiling text P25-188 20260309- 14 -

[0031] The polysilazane may comprise only a single type of end group represented by formula (3) or two or more types thereof. The polysilazane may comprise -NH2 as an end group.

[0032] The polysilazane has a mass average molecular weight (Mw) of preferably 5 500 to 10,000, more preferably 700 to 8,000, still more preferably 900 to 6,000, and even more preferably 1 ,000 to 4,000.It is believed that polysilazane with a Mw of 500 or more is sufficiently oxidized by plasma irradiation. It is believed that polysilazane with a Mw of 10,000 or less is sufficiently dissolved in the solvent.Mw as used in this disclosure is measured by gel permeation chromatography (GPC) using polystyrene as a standard. Mw is measured using monodisperse polystyrene as a standard sample and tetrahydrofuran as a developing solvent under measurement conditions of a flow rate of 0.5 mL / min and a column temperature of 40°C. Mw is calculated as the molecular weight relative to the 15 standard sample.

[0033] The ratio of the number of units A to the number of units B in the polysilazane is preferably 0.5 to 2, more preferably 0.7 to 1.8, and still more preferably 0.8 to 1.5.It is believed that the ratio of 0.5 or more provides a more uniform silicon- 20 containing film formed by plasma irradiation. It is believed that the ratio of 2 or less shortens the time of plasma irradiation required for forming the silicon-containing film.

[0034] The ratio of the total number of units A and B to the number of end groups in the polysilazane is preferably 1.2 to 2.5, more preferably 1.3 to 2.4, still more preferably 1.4 to 2.0, and even more preferably 1.5 to 1.7. It is believed that the ratio of 1.2 or more promotes the oxidation of silicon by plasma irradiation more efficiently and increases the hardness of the silicon-containing film. It is believed that the ratio of 2.5 or less enhances the embeddability of the composition or the silicon-containing film into a structural substrate.30

[0035] The composition may comprise a polymer (hereinafter referred to as other polymers) other than polysilazane. Given that the mass of polysilazane in the composition is taken as mA, and the total mass of polysilazane and other polymersForeignfiling text P25-188 20260309- 15 -is taken as mtotai, mA / mtotai is preferably 80% or more, more preferably 90% or more, and still more preferably 95% or more.An embodiment in which mA / mtotai is 100%, that is, the composition is free of any other polymers is also a preferred embodiment of the present invention.5

[0036] SolventThe composition may further comprise a solvent. Preferably, the solvent is one or more kinds selected from the group consisting of an aromatic compound, more preferably benzene, toluene, xylene, ethylbenzene, diethylbenzene, trimethylbenzene, and triethylbenzene; saturated hydrocarbon compounds, more preferably, n-pentane, i-pentane, n-hexane, i-hexane, n-heptane, i-heptane, n- octane, i-octane, n-nonane, i-nonane, n-decane, cyclohexane, methylcyclohexane, ethylcyclohexane, decahydronaphthalene, and p-menthane; unsaturated hydrocarbon compounds, more preferably, cyclohexene and dipentene; ether compounds, more preferably, dipropyl ether, dibutyl ether, propylene glycol15 monomethyl ether, propylene glycol monomethyl ether acetate, and anisole; ester compounds, more preferably n-butyl acetate, i-butyl acetate, n-amyl acetate, i-amyl acetate, and ethyl lactate; and ketone compounds, more preferably methyl isobutyl ketone; still more preferably, dipropyl ether, dibutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, or anisole; and 20 even more preferably dibutyl ether.

[0037] It is believed that using the above solvent decreases the viscosity of the composition and enables the more uniform application of the composition above a substrate.

[0038] The boiling point of the solvent is preferably 60°C to 200°C, more preferably 70°C to 180°C, still more preferably 80°C to 160°C, and even more preferably 80°C to 145°C. The boiling point of the solvent in the present disclosure refers to a boiling point at 1 atm.

[0039] The molecular weight of the solvent is preferably 40 to 160, more preferably 50 to 150, and still more preferably 60 to 140. The molecular weight of 30 the solvent in the present disclosure can be measured by methods well known to a person skilled in the art, such as a freezing point depression method.Foreignfiling text P25-188 20260309- 16 -

[0040] The solid component content of the composition is preferably 30 to 75 mass%, more preferably 35 to 70 mass%, still more preferably 40 to 65 mass%, and even more preferably 45 to 50 mass%, based on the total mass of the composition. In the present disclosure, solid components in a composition refer to 5 all components of the composition, except solvents.It is believed that a composition having a solid component content of 30 mass% or more facilitates the formation of the film of the composition above a substrate. It is believed that a composition having a solid component content of 75 mass% or less enables the more uniform application of the composition above a substrate.

[0041] The polysilazane content of the composition is preferably 70 to 100 mass%, more preferably 80 to 100 mass%, and still more preferably 90 to 100 mass%, based on the total mass of the solid components in the composition.

[0042] Optional Component15 The composition may further comprise an optional component. Examples of optional components include a silanol condensation catalyst, a fluorine-containing compound, an adhesion promoter, a corrosion-resistant additive, a cross-linking agent, a dispersant, a filler, a functional dye (such as those imparting functional effects, including electric conductivity, thermal conductivity, magnetic properties, or 20 the like), nanoparticles, optical dyes (such as those imparting optical effects, including color tone, refractive index, pearlescent effects, or the like), particles that reduce thermal expansion, a polymerization initiator, a polymerization inhibitor, a primer, a rheology modifier (such as a thickener), and a binding enhancer. Optional components are different from polysilazane and the solvent.The optional component content (when a plural types of optional components are used, the total content) is preferably 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, still more preferably 0 to 1 part by mass, and even more preferably 0 to 0.5 parts by mass, based on 100 parts by mass of the polysilazane. It is also one preferable embodiment in which the composition is free of optional30 components.

[0043] Examples of silanol condensation catalysts include a photoacid generator, a photobase generator, a thermal acid generator, and a thermal base generator. InForeignfiling text P25-188 20260309the present disclosure, a photoacid generator or a photobase generator refers to a compound that undergoes bond cleavage by exposure to light to generate an acid or a base. Examples of light include visible light, ultraviolet rays, infrared, X-rays, electron beams, a-rays, and y-rays. In the present disclosure, a thermal acid 5 generator or a thermal base generator refers to a compound that undergoes bond cleavage by heat to generate an acid or a base. It is believed that the generated acid or base contributes to the polymerization reaction of the siloxane compound.

[0044] Examples of photoacid generators include a diazomethane compound, a triazine compound, a sulfonate ester, an iodonium salt such as a diphenyliodonium salt, a sulfonium salt such as a triphenylsulfonium salt, an ammonium salt, a phosphonium salt, and a sulfonimide compound.

[0045] Examples of photobase generators include a polysubstituted amide compound having an amido group, a lactam, an imide compound; and an ionic photobase generator containing, as an anion, an amide anion, a methide anion, a 15 borate anion, a phosphate anion, a sulfonate anion, or a carboxylate anion.

[0046] Examples of thermal acid generators include an aliphatic sulfonic acid and a salt thereof; an aliphatic carboxylic acid, such as citric acid, acetic acid, maleic acid, and a salt thereof; an aromatic carboxylic acid, such as benzoic acid and phthalic acid, and a salt thereof; an aromatic sulfonic acid and a salt thereof; an 20 aromatic diazonium salt; and a phosphonic acid and a salt thereof.

[0047] Examples of thermal base generators include a compound that generates a base, such as imidazole and a tertiary amine.

[0048] Examples of fluorine-containing compounds include a fluorine-containing surfactant having a fluorinated hydrocarbon group and a hydrophilic group, such as MEGAFACE (DIC), FLUORAD (3M), and Surfion (AGC Seimi Chemical).

[0049] The composition may comprise a surfactant other than the fluorine- containing surfactants. Examples of other surfactants include a nonionic surfactant, an anionic surfactant, and an amphoteric surfactant.

[0050] The nanoparticles may be selected from particles of a nitride, a titanate, 30 diamond, an oxide, a sulfide, a sulfite, a sulfate, a silicate, and a carbide. The nanoparticles may optionally be surface-modified using a capping agent. The particle size of the nanoparticles may be, for example, 1 to 100 nm, 1 to 50 nm, or 1Foreignfiling text P25-188 20260309- 18 -to 25 nm. The particle size can be measured by any standard method known to a person skilled in the art.

[0051] Examples of polymerization initiators include a polymerization initiator that generates an acid, a base, or a radical with radiation, and a polymerization initiator 5 that generates an acid, a base, or a radical with heat. Examples of the radiation include visible light, ultraviolet rays, infrared, X-rays, electron beams, a-rays, and y- rays.

[0052] Examples of photo-radical generators include an azo-based generator, a peroxide-based generator, an acylphosphine oxide-based generator, an alkylphenone-based generator, an oxime ester-based generator, and a titanocene- based generator. Among others, an alkylphenone-based generator, an acylphosphine oxide-based generator, and an oxime ester-based generator are preferred, and 2,2-dimethoxy-1,2-diphenylethan-1-one, 1 -hydroxy-cyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2- 15 hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1 -propan-1 -one, 2-hydroxy-1 -{4-[4-(2- hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropan-1 -one, 2-methyl-1 -(4- methylthiophenyl)-2-morpholinopropan-1 -one, 2-benzyl-2-dimethylamino-1 -(4- morpholinophenyl)1 -butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1 -[4- (4-morpholinyl)-phenyl]-1-butanone, 2,4,6-trimethylbenzoyldiphenylphosphine 20 oxide, bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide, 1 ,2-octanedione,1-[4- (phenylthio)phenyl]-,2-(O-benzoyloxime), ethanone, 1 -[9-ethyl-6-(2-methylbenzoyl)- 9H-carbazol-3-yl]-,1-(O-acetyloxime) and the like can be used.

[0053] Examples of polymerization inhibitors include an ultraviolet absorber, and a nitrone, a nitrogen oxide radical, hydroquinone, catechol, phenothiazine, phenoxazine, a hindered amine, and a derivative thereof. Specifically, methylhydroquinone, catechol, 4-t-butylcatechol, 3-methoxycatechol, phenothiazine, chlorpromazine, phenoxazine, TINUVIN 144, 292, and 5100 (BASF) as hindered amines, and TINUVIN 326, 328, 384-2, 400, and 477 (BASF) as ultraviolet absorbers may be used.30

[0054] A binding enhancer has the effect of preventing a film from being peeled off from a substrate due to stress applied when the composition according to one embodiment is applied above a substrate to form the film and cured by heating. AsForeignfiling text P25-188 20260309- 19 -the binding enhancer, an imidazole compound, a silane coupling agent, and the like are preferred. Examples of imidazole compounds include 2-hydroxybenzimidazole, 2-hydroxyethylbenzimidazole, benzimidazole, 2-hydroxyimidazole, imidazole, 2- mercaptoimidazole, and 2-aminoimidazole.5

[0055] Examples of silane coupling agents include an epoxysilane coupling agent, an aminosilane coupling agent, and a mercaptosilane coupling agent. Specifically, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, N-(2- aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3- aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3- aminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, 3- chloropropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3- isocyanatopropyltriethoxysilane, and the like may be used.

[0056] As the silane coupling agent, a silane compound having an acid group may also be used. Examples of acid groups include a carboxy group, an acid 15 anhydride group, and a phenolic hydroxy group.

[0057] The composition can form a silicon-containing film having excellent film hardness and electrical properties, and thus is useful as a composition for producing an electronic device, particularly a composition for producing a semiconductor device. The composition may be used, for example, for forming a 20 silicon-containing film above a substrate. Examples of substrates include a silicon substrate, a glass substrate, and a resin film.

[0058] Considering that the composition is used for producing an electronic device and, as a more preferred embodiment, for producing a semiconductor device, it is preferred that the composition has a low content of alkali metal and alkaline earth metal. The total concentration of the alkali metal and alkaline earth metal of the composition is preferably 1 ppm or less, more preferably 100 ppb or less, and still more preferably 10 ppb or less.

[0059] (Application of Composition above Substrate and Formation of Film)In the step (A), the composition is applied above a substrate to form a film. 30 The phrase “above a substrate” means that the composition may be applied directly onto the substrate or applied via one or more other layers. Examples of other layers include SOC (Spin On Carbon) and adhesion-enhancing films.Foreignfiling text P25-188 20260309- 20 -Preferably, the composition is applied directly onto a substrate.

[0060] The film may be formed in the step (A) according to any method that has been conventionally known as the method for applying a composition. Specific examples thereof include dip coating, roller coating, bar coating, brush coating, 5 spray coating, doctor blade coating, flow coating, spin coating, and slit coating, and spin coating is preferred.

[0061] When a film is formed by spin coating, the composition is spin-coated on a substrate preferably at 200 to 4,000 RPM, more preferably 300 to 3,500 RPM, and still more preferably 500 to 3,000 RPM.The composition is spin-coated on a substrate by maintaining the rotation for preferably 0.1 to 100 seconds, more preferably 0.3 to 70 seconds, and still more preferably 0.5 to 40 seconds.

[0062] Spin coating can be conducted two or more times at the same or different RPM and retention time.15

[0063] Examples of substrates include a silicon substrate, a glass substrate, and a resin film. Preferably, the substrate is a silicon substrate.

[0064] [Step (B)]In the step (B), plasma is irradiated to the film under an atmosphere that comprises the gas (G) comprising a hydrogen atom and an oxygen atom. The 20 plasma can be irradiated using a plasma irradiation apparatus. Examples of plasma irradiation apparatuses include a parallel plate capacitively coupled plasma (CCP) apparatus having a pair of opposing electrodes, an inductively coupled plasma (ICP) apparatus, a microwave plasma apparatus, and a remote plasma apparatus.The plasma irradiation apparatus is preferably a parallel plate capacitively coupled plasma apparatus. The plasma irradiation apparatus may be an atmospheric pressure plasma apparatus or a reduced pressure plasma apparatus, and is preferably a reduced pressure plasma apparatus.

[0065] It is considered that the plasma irradiation to polysilazane under an atmosphere comprising the gas (G) makes it possible to form a sufficiently oxidized 30 silicon-containing film while suppressing the occurrence of residual stress andcracks.Foreignfiling text P25-188 20260309- 21 -

[0066] The mechanism of action of the production of the silicon-containing film in the step (B) is believed to be as follows.Irradiating plasma to the film formed from the composition under an atmosphere comprising the gas (G) generates an *OH radical. The *OH radical 5 activates an NH or SiH bond and generate NH3 at the same time as silicon oxidation. The NH3 generated exhibits a catalyst action for the silicon oxidation of the polysilazane, progressing the silicon oxidation efficiently.

[0067] The degree of oxidation of the silicon-containing film can be confirmed by measuring the refractive index of the silicon-containing film. The refractive index can be measured using a well-known measuring instrument, such as an ellipsometer.The degree of oxidation of the silicon-containing film can also be confirmed on the basis of the presence or absence of a peak in the vicinity of 1 ,080 cm’1, to which O-Si-O belongs, in a measured FT-IR spectrum of the silicon-containing film.15

[0068] A molecule constituting the gas (G) preferably includes one or two hydrogen atoms, one or more oxygen atoms, or both, and more preferably one or two hydrogen atoms, one or two oxygen atoms, or both.

[0069] The gas (G) may be mixed gas of gas (G1 ) comprising a hydrogen atom, and gas (G2) comprising a hydrogen atom, an oxygen atom, or both other than the 20 gas (G1).

[0070] <First Embodiment of Mixed Gas>Examples of the gas (G1) include water vapor, H2O2, H2, HCOOH, and CH4, and the gas (G1) is preferably water vapor, H2O2, or H2, and more preferably water vapor.

[0071] Examples of the gas (G2) include O2, O3, CO2, CO, and N2O, and the gas (G2) is preferably O2 or CO2.

[0072] <Second Embodiment of Mixed Gas>The gas (G1 ) is water vapor.

[0073] Examples of the gas (G2) include H2O2, H2, HCOOH, CH4, O2, O3, CO2, 30 CO, and N2O, and the gas (G2) is preferably H2O2, H2, O2, or CO2.

[0074] The gas (G) is preferably water vapor, H2O2, mixed gas of H2 and O2, mixed gas of H2 and CO2, mixed gas of H2 and CO, mixed gas of CH4 and O2,Foreignfiling text P25-188 20260309- 22 -mixed gas of H2 and N2O, or HCOOH, more preferably water vapor, H2O2, mixed gas of H2 and O2, or mixed gas of H2 and CO2, still more preferably water vapor, or mixed gas of H2 and O2, and even more preferably water vapor.

[0075] When the gas (G) is the gas described above, it is believed that the silicon 5 oxidation of polysilazane proceeds more efficiently. When the gas (G) is water vapor, it is believed that the catalyst action described above works well, progressing the silicon oxidation of polysilazane more efficiently.

[0076] The atmosphere comprising the gas (G) can be formed, for example, by supplying the gas (G) into the reaction chamber of the plasma irradiation apparatus. The atmosphere comprising the gas (G) means an atmosphere in which the partial pressure of the gas (G) in a plasma irradiation atmosphere, such as in a reaction chamber of a plasma irradiation apparatus, is for example, 0.01 to 1.0 times, preferably 0.5 to 1.0 times, more preferably 0.6 to 1.0 times, and still more preferably 0.7 to 1.0 times the total pressure in the atmosphere.15 Here, when the gas (G) is a mixture of two or more types of gases, the partial pressure refers to the sum of the partial pressures of the two or more types of gases.

[0077] When the gas (G) is mixture gas of the gas (G1 ) and the gas (G2), given that the partial pressure of the gas (G1) is taken as PGI, and the partial pressure of 20 the gas (G2) is PG2, PG2 / PGI is preferably 35% or less, more preferably 20% or less, still more preferably 10% or less, and even more preferably 5% or less.An embodiment in which PG2 / PGI is 0%, that is, the gas (G) only comprises the gas (G1), is also a preferred embodiment of the present invention.

[0078] In the step (B), gas other than the gas (G) (hereinafter referred to as gas (g)) may be present in the plasma irradiation atmosphere. The gas (g) may be a mixture of two or more types of gases.Given that the partial pressure of the gas (G) in a plasma irradiation atmosphere is taken as PG, and the sum of the partial pressures of gas (G) and gas (g) is taken as Ptotai, Pc / Ptotai is preferably 80% or more, more preferably 90% or 30 more, and still more preferably 95% or more.Foreignfiling text P25-188 20260309- 23 -An embodiment in which Pc / Ptotai is 100%, that is, the gas (g) is absent in a plasma irradiation atmosphere, is also a preferred embodiment of the present invention.

[0079] Examples of the gas (g) include N2, Ar, He, Ne, Kr, or a combination of any 5 of these.

[0080] The temperature in the step (B) is preferably 10°C to 150°C, more preferably 10°C to 100°C, still more preferably 10°C to 60°C, and even more preferably 10°C to 30°C.It is believed that conducting the step (B) at temperature of 150°C or lower more efficiently reduces the stress remaining in the silicon-containing film and suppresses the occurrence of cracks in the silicon-containing film.In addition, it is believed that conducting the step (B) at temperature of 10°C or higher more efficiently promotes silicon oxidation.

[0081] The total pressure in the step (B) is preferably 1 to 101,500 Pa, more 15 preferably 1 to 5,000 Pa, still more preferably 1 to 1,000 Pa, even more preferably 1 to 500 Pa, and particularly preferably 5 to 50 Pa. The total pressure in the step (B) means the total pressure in the plasma irradiation atmosphere.It is believed that setting the total pressure in the step (B) to 1 Pa or higher provides a silicon-containing film in which silicon is more uniformly oxidized. It is 20 believed that setting the total pressure in the step (B) to 101 ,500Pa or lower can enlarge the area of the film that can be irradiated with plasma at one time. It is believed more advantageous to set the total pressure in the step (B) to 5,000 Pa or lower in view of further enlarging the area of the film that can be irradiated with plasma.

[0082] The output of plasma in the step (B) is preferably 20 to 500 W, more preferably 30 to 400 W, still more preferably 40 to 300 W, and even more preferably 50 to 250 W

[0083] The plasma irradiation time in the step (B) is preferably 20 to 1 ,200 seconds, more preferably 30 to 1 ,000 seconds, still more preferably 40 to 600 30 seconds, and even more preferably 50 to 300 seconds.Foreignfiling text P25-188 20260309- 24 -

[0084] In the step (B), the plasma irradiation dosage determined by equation (a) is preferably 2,000 to 200,000 J, more preferably 4,000 to 30,000 J, still more preferably 5,000 to 25,000 J, and even more preferably 5,000 to 20,000 J.Plasma output (W) x Plasma irradiation time (s) = Plasma irradiation dosage 5 (J) ... (a)It is believed that setting the plasma irradiation dosage to 200,000 J or less prevents the film structure from breaking and provides a silicon-containing film having sufficient mechanical strength. It is believed that setting the plasma irradiation dosage to 2,000 J or more can promote silicon oxidation.

[0085] The step (B) preferably comprises the following steps (b-1 ), (b-2), and (b- 3):(b-1 ) placing, on the lower electrode out of a pair of opposing electrodes in a reaction chamber of a plasma irradiation apparatus, a substrate with a film formed above the substrate;15 (b-2) supplying gas (G) into the reaction chamber to create an atmosphere comprising the gas (G) within the reaction chamber; and(b-3) irradiating plasma to the film.

[0086] The plasma irradiation apparatus in the step (b-1) is a parallel plate capacitively coupled plasma apparatus having a pair of opposing electrodes. The 20 electrode-to-electrode distance in the parallel plate capacitively coupled plasma apparatus is preferably 1 to 30 cm, more preferably 3 to 20 cm, still more preferably 5 to 15 cm. The area of the electrode is preferably 10 to 1000 cm2, more preferably 70 to 1000 cm2, and still more preferably 100 to 800 cm2.The parallel plate capacitively coupled plasma apparatus has a high-frequency power source, and the frequency of the high-frequency power source can generally be set, as appropriate, within the range of 1 kHz to 10 GHz, and for example, can be set to 13.56 MHz. The waveform output from the high-frequency power supply may be, for example, a sine wave, a rectangular wave, a triangular wave, a sawtooth wave or a pulse wave, and is preferably a sine wave.30

[0087] In the step (b-2), the gas (G) is supplied into the reaction chamber preferably at a flow rate of 5 to 100 seem, more preferably 10 to 50 seem, and still more preferably from 15 to 30 seem. The place where the gas (G) is introduced intoForeignfiling text P25-188 20260309- 25 -the reaction chamber is not particularly limited. This makes the inside of the reaction chamber an atmosphere comprising the gas (G).

[0088] In the step (b-3), the gas (G) may be continuously supplied into the reaction chamber, the supply of the gas (G) may be suspended, or the gas (G) may 5 be intermittently supplied, during the irradiation of plasma to the film. When the gas (G) is supplied into the reaction chamber, the flow rate thereof is the same as the range described with regard to the step (b-2).In the step (b-3), the atmosphere comprising the gas (G) in the reaction chamber may continue to be maintained, or the inside of the reaction chamber may not be under an atmosphere comprising the gas (G) for a period of time. In the step (b-3), it is preferred to continue to maintain an atmosphere comprising the gas (G) within the reaction chamber.

[0089] In the step (b-3), the plasma irradiation density determined by equation (P) is preferably 2 to 200 J / cm2, more preferably 4 to 30 J / cm2, still more preferably 5 to 15 25 J / cm2, and even more preferably 5 to 20 J / cm2.It is believed that setting the plasma irradiation density to 200 J / cm2or less suppresses the conversion of only the film surface to silicon dioxide at a high density and can oxidize silicon more uniformly over the entire film. It is believed that setting the plasma irradiation density to 2 J / cm2or more can promote silicon20 oxidation.Plasma irradiation density (J / cm2) =Plasma irradiation dosage (J) I Area of surface of lower electrode in contact with substrate (cm2) ... (P)

[0090] The details of the gas (G) in the step (b-2) and the temperature, total pressure, plasma output, plasma irradiation time, and plasma irradiation dosage in the step (b-3) are the same as those described above.

[0091] [Step (A-2)]It is preferred that the method of the present invention further comprises the following step (A-2) between the step (A) and the step (B):30 (A-2) heating the film.Foreignfiling text P25-188 20260309- 26 -

[0092] In the step (A-2), the temperature for heating the film is preferably 50°C to 290°C, more preferably 60°C to 270°C, still more preferably 70°C to 250°C, and even more preferably 100°C to 200°C.The heating time in the step (A-2) is preferably 50 to 1 ,000 seconds, more 5 preferably 100 to 500 seconds, still more preferably 120 to 300 seconds, and even more preferably 150 to 200 seconds.It is believed that heating the film at 50°C or higher in the step (A-2) reduces the amount of solvent remaining in the film and allows the film to be dried more efficiently. It is believed that heating the film at 290°C or lower in the step (A-2) allows silicon contained in the polysilazane to be more easily oxidized during plasma irradiation.

[0093] The heating can be performed, for example, using at least one apparatus selected from a hot plate and a clean oven. The heating may be conducted under an oxidizing atmosphere, such as in air, or under a non-oxidizing atmosphere, such 15 as in an inert gas, and is preferably conducted under an oxidizing atmosphere.

[0094] The step (A-2) may be conducted two or more times at the same or different heating temperatures, heating times, and atmosphere.

[0095] [Step (C)]It is preferred that the method of the present invention further comprises the 20 following step (C) after the step (B):(C) heating the film.

[0096] In the step (C), the temperature for heating the film is 300°C to 1 ,000°C, preferably 350°C to 950°C, more preferably 400°C to 900°C, and still more preferably 500°C to 850°C.The time for heating the film in the step (C) is 500 to 3,000 seconds, preferably 700 to 2,800 seconds, more preferably 900 to 2,500 seconds, and still more preferably 1 ,200 to 2,000 seconds.It is believed that heating the film in the step (C) at 300°C to 1 ,000°C makes it possible to further promote silicon oxidation while suppressing the occurrence of 30 residual stress and cracks.

[0097] The heating can be performed, for example, using at least one apparatus selected from a hot plate and a clean oven. The heating may be conducted underForeignfiling text P25-188 20260309- 27 -an oxidizing atmosphere, such as in air, or under a non-oxidizing atmosphere, such as in an inert gas, and is preferably conducted under an oxidizing atmosphere.

[0098] The oxidizing atmosphere refers to an atmosphere in which the oxygen partial pressure is 20 to 101 kPa when the total pressure is 101 kPa.5

[0099] The non-oxidizing atmosphere refers to an atmosphere having an oxygen concentration of 1 ppm or lower and a dew point of -76°C or lower. Preferably, it is an atmosphere of N2, Ar, He, Ne, and H2, or a gas mixture of any combination thereof.

[0100] The step (C) may be conducted two or more times at the same or different heating temperatures, heating times, and atmosphere.

[0101] The film thickness of the silicon-containing film is preferably 50 to 3,000 nm, more preferably 70 to 1 ,500 nm, still more preferably 90 to 1 ,200 nm, and even more preferably 100 to 1 ,000 nm. In the present disclosure, the film thickness of the silicon-containing film is a value measured by Ellipsometer M-2000 (J. A. Woollam).15

[0102] The silicon-containing film has excellent film hardness and electrical characteristics, and thus is useful as an insulation film for electronic devices. The silicon-containing film may be used, for example, as a surface protective film, a buffer coat film, or an interlayer insulation film of semiconductor devices.

[0103] <Method for Producing Electronic Device>20 A method for producing an electronic device according to one embodiment comprises the method for producing the silicon-containing film described above. Examples of electronic devices include an electronic component, such as a semiconductor device, a capacitor, and a printed circuit board, a solar cell chip, an organic light-emitting diode, and an inorganic light-emitting diode. Preferably, the electronic device is a semiconductor device.

[0104] Preferably, the method for producing an electronic device comprises the following steps (I) and (II):(I) forming a silicon-containing film by the method of the present invention; and (II) processing a substrate.30

[0105] [Step (I)]Details of a method for forming a silicon-containing film are described in the section <Method for Producing Silicon-Containing Film>.Foreignfiling text P25-188 20260309- 28 -

[0106] [Step (II)]Processing of the substrate in the step (II) may comprise inspection, formation of other films, ion doping, etching, removing impurities, dicing, bonding, packaging, mounting, and combinations of any of these.5 [Examples]

[0107] The present invention will be described as follows with reference to a variety of examples. It should be noted that the embodiments of the present invention are not limited to these examples.

[0108] In the following Examples, Mw is measured by gel permeation chromatography (GPC) with polystyrene as a standard. GPC is carried out using Waters ACQUITYAPC System (Nihon Waters), Shodex GPC HK-401 column and Shodex GPC HK-404L column (Shoko Science). The measurement is performed using monodisperse polystyrene as a standard sample and tetrahydrofuran as a developing solvent under measurement conditions of a flow rate of 0.5 mL / min and 15 a column temperature of 40°C. Mw is calculated as the molecular weight relative to the standard sample.

[0109] Unless stated otherwise, all steps in the present Examples are performed at a temperature of 20°C.

[0110] <Synthesis of Polysilazane A>20 The inside of a 10-L reaction vessel equipped with a cooling condenser, a mechanical stirrer, and a temperature controller is replaced with nitrogen. Then, 7,500 mL of dehydrated pyridine is charged into the reaction vessel and cooled to - 3°C. An addition of 500 g of dichlorosilane thereto produces a white solid (SiH2Cl2'2C5HsN). While stirring, 350 g of ammonia is slowly blown into the reaction vessel. The resulting mixture is further stirred for 30 minutes. Nitrogen is blown into the liquid layer for 30 minutes to evacuate excess ammonia. The resulting slurry product is subjected to pressure filtration using a fluororesin filter having a pore diameter of 0.2 pm under a nitrogen atmosphere to obtain 6,000 mL of filtrate. Then, 2,640 g of dehydrated xylene is added to the filtrate, and pyridine is distilled 30 off using an evaporator to concentrate the filtrate. A solution containing polysilazane (polysilazane A) having a solid component content of 39.8 mass% with respect to the total mass of the composition is obtained.Foreignfiling text P25-188 20260309- 29 -The polysilazane A is perhydropolysilazane. Mw is 1,401.

[0111] Production and Preparation of Silicon-Containing Films>(Example 1)Polysilazane A is applied to a 4-inch silicon wafer using a spin coater MS-B150 5 (Mikasa) while holding 1 ,000 rpm for 10 seconds. The coated matter is heated over a hot plate NHA-3030 (AS ONE) for 3 minutes at 150°C to form a film having a film thickness of 120 nm. The film thickness is measured using Ellipsometer M-2000V (J. A. Woollam).A wafer with a film formed thereon is placed on the lower electrode out of a pair of parallel plate electrodes in the reaction chamber of the plasma irradiation apparatus AQ-500 #1 (SUMCO). The electrode-to-electrode distance is 10 cm, and the electrode area is 1 ,000 cm2. A current of 13.56 MHz is applied at 20°C to generate plasma on the surfaces of the pair of parallel plate electrodes. Water vapor is supplied at 20 seem into the reaction chamber, and the pressure in the 15 reaction chamber is maintained at 10 Pa for 20 seconds. Plasma is irradiated to the film at an output of 250 W for 1 minute to obtain a silicon-containing film of Example 1.

[0112] (Example 2)A silicon-containing film of Example 2 is produced by the same procedure as in 20 Example 1 , except that the output of the plasma irradiation apparatus is changed to 100 W

[0113] (Example s)A silicon-containing film of Example 3 is produced by the same procedure as in Example 1 , except that the output of the plasma irradiation apparatus is changed to 50 W, and the plasma irradiation time is changed to 5 minutes.

[0114] (Comparative Example 1)A silicon-containing film of Comparative Example 1 is produced by the same procedure as in Example 1 , except that plasma irradiation is not conducted.

[0115] (Reference Example 1)30 A 4-inch wafer with a thermally oxidized film (SEIREN KST) is prepared. This is referred to as a silicon-containing film of Reference Example 1.

[0116] <Thermal Curing>Foreignfiling text P25-188 20260309- 30 -(Example 4)As described in the section Production and Preparation of Silicon-Containing Films>, a silicon-containing film of Example 1 is produced. The silicon-containing film is placed in an annealing furnace VF-1000 (JTE KT THERMO SYSTEMS) and heated at 850°C for 30 minutes under a nitrogen atmosphere to obtain a silicon-containing film of Example 4.

[0117] (Comparative Example 2)As described in the section Production and Preparation of Silicon-Containing Films>, a silicon-containing film of Comparative Example 1 is produced. The silicon-containing film is placed in VF-1000 and heated at 450°C for 30 minutes and at 600°C for 5 minutes under a nitrogen atmosphere. A silicon-containing film of Comparative Example 2 is obtained.

[0118] (Comparative Example 3)As described in the section Production and Preparation of Silicon-Containing Films>, a silicon-containing film of Comparative Example 1 is produced. The silicon-containing film is placed in VF-1000 and heated at 400°C for 30 minutes and at 600°C for 30 minutes under a water vapor atmosphere. Further, the silicon-containing film is heated at 600°C for 30 minutes under a nitrogen atmosphere to obtain a silicon-containing film of Comparative Example 3.

[0119] <Evaluation of Film Thickness and Refractive lndex>The film thicknesses, and the refractive indices at a wavelength of 633 nm of the silicon-containing films of Examples 1, 2, 3, and 4, Comparative Examples 1 and 2, and Reference Example 1 are determined using M-2000V. The results are shown in Table 1 below.

[0120] [Table 1]Foreignfiling text P25-188 20260309Table 1Refractive index Film thickness (nm)Example 1 1.45 127Example 2 1.45 129Example 3 1.45 129Example 4 1.44 113Comp. Ex. 1 1.55 122Comp. Ex. 2 2.02 125Ref. Ex. 1 1.46 150

[0121] structural Analysis>The FT-IR spectra of the silicon-containing films of Examples 1 , 2, 3, and 4, 5 Comparative Example 1, and Reference Example 1 are measured using a Fourier transform infrared (FT-IR) spectrophotometer FT-IR-6100 (JASCO). The peaks of Example 1, Comparative Example 1, and Reference Example 1 are shown in Fig. 1, the peaks of Examples 1 , 2, and 3 are shown in Fig. 2, and the peaks of Examples 1 and 4 are shown in Fig. 3.10 The spectra of Examples 1 , 2, and 3 are found to show a peak around 1 ,080 cm-1, to which O-Si-O belongs, as in the spectrum of Reference Example 1.It is also found that the peak around 1 ,080 cm-1in Example 4 is higher than that in Example 1.

[0122] Evaluation of Relative Wet Etching Rate (RWER)>As described in the section Production and Preparation of Silicon-Containing Films>, silicon-containing films of Example 1 and Comparative Example 1 are produced, and a silicon-containing film of Reference Example 1 is prepared.The silicon-containing film of Example 1 is immersed in a 1.0 mass% aqueous hydrofluoric acid solution at 20°C. Twenty seconds after the start of the immersion, 20 the silicon-containing film is taken out from the aqueous hydrofluoric acid solution.The silicon-containing film is rinsed twice with pure water and exposed to nitrogen gas at 20°C to dry the film.The film thickness of the silicon-containing film is measured using M-2000V. After the measurement, the silicon-containing film is again immersed in a 1.0Foreignfiling text P25-188 20260309mass% aqueous hydrofluoric acid solution. After the lapse of 1 , 2, 4, 6, and 8 minutes each from the start of the immersion, the film thicknesses are measured according to the same procedure, and the relationship between the immersion time and the amount of decrease in the film thickness is linearly approximated, and the 5 inclination thereof is regarded as a wet etching rate (WER). WERs of the silicon- containing films of Comparative Example 1 and Reference Example 1 are determined by the same procedure. The value obtained by dividing each WER by the WER of the silicon-containing film of Reference Example 1 is taken as RWER. The results are shown in Table 2 below.10

[0123] [Table 2]Table 2WER (nm / min) RWER (nm / min)Example 1 23.6 11Comp. Ex. 1 366 174Ref. Ex. 1 2.1 1

[0124] Measurement of Residual Stress>The residual stresses of the silicon-containing film of Example 1 produced as described in the section Production and Preparation of Silicon-Containing Films>, and the silicon-containing film of Comparative Example 3 produced as described in the section <Thermal Curing>, are measured using FLX-3300-T (Toho Technology). The results are shown in Table 3 below.

[0125] [Table 3]20 Table 3Residual stress (MPa)Example 1 5Comp. Ex. 3 137

Claims

Foreignfiling text P25-188 20260309- 33 -CLAIMS

1. A method for producing a silicon-containing film comprising the following steps 5 (A) and (B):(A) applying a composition comprising polysilazane above a substrate to form a film; and(B) irradiating plasma to the film under an atmosphere that comprises gas (G) comprising a hydrogen atom and an oxygen atom.

2. The method according to claim 1, wherein a partial pressure of the gas (G) in the atmosphere of the step (B) is 0.01 to 1.0 times, preferably 0.5 to 1.0 times, more preferably 0.6 to 1.0 times, and still more preferably 0.7 to 1.0 times a total 15 pressure in the atmosphere.

3. The method according to claim 1 or 2, wherein the gas (G) is mixture gas of gas (G1) and gas (G2), and given that the gas (G1) has a partial pressure of PGI, 20 and the gas (G2) has a partial pressure of PG2, PG2 / PGI is 35% or less, preferably 20% or less, more preferably 10% or less, and still more preferably 5% or less.

4. The method according to any one of claims 1 to 3, wherein a temperature in the step (B) is 10°C to 150°C, preferably 10°C to 100°C, more preferably 10°C to 60°C, and still more preferably 10°C to 30°C.

5. The method according to any one of claims 1 to 4, wherein a total pressure in 30 the step (B) is 1 to 101,500 Pa, preferably 1 to 5,000 Pa, more preferably 1 to 1,000 Pa, still more preferably 1 to 500 Pa, and even more preferably 5 to 50 Pa.Foreignfiling text P25-188 20260309- 34 -

6. The method according to any one of claims 1 to 5, wherein an output of plasma in the step (B) is 20 to 500 W, preferably 30 to 400 W, more preferably 40 to 300 W, and still more preferably 50 to 250 W.5

7. The method according to any one of claims 1 to 6, wherein a plasma irradiation time in the step (B) is 20 to 1 ,200 seconds, preferably 30 to 1 ,000 seconds, more preferably 40 to 600 seconds, and still more preferably 50 to 300 seconds.

8. The method according to any one of claims 1 to 7, wherein a plasma irradiation dosage determined by equation (a) in the step (B) is 2,000 to 200,000 J, preferably 4,000 to 30,000 J, more preferably 5,000 to 25,000 J, and still more preferably 15 5,000 to 20,000 J.Plasma output (W) x Plasma irradiation time (s) = Plasma irradiation dosage (J) ... (a)

9. 20 The method according to any one of claims 1 to 8, wherein the step (B) comprises the following steps (b-1 ), (b-2), and (b-3):(b-1) placing a substrate with a film formed above the substrate on a lower electrode out of a pair of opposing electrodes in a reaction chamber of a plasma irradiation apparatus;(b-2) supplying gas (G) into the reaction chamber to create an atmosphere comprising the gas (G) within the reaction chamber; and(b-3) irradiating plasma to the film.

10. 30 The method according to claim 9, wherein a plasma irradiation density determined by equation ([3) in the step (b-3) is 2 to 200 J / cm2, preferably 4 to 30 J / cm2, more preferably 5 to 25 J / cm2, and still more preferably 5 to 20 J / cm2.Foreignfiling text P25-188 20260309- 35 -Plasma irradiation density (J / cm2) =Plasma irradiation dosage (J) I Area of surface of lower electrode in contact with substrate (cm2) ... ([3)

11. The method according to claim 9 or 10, wherein the gas (G) is suppled in the step (b-2) at a flow rate of 5 to 100 seem, preferably 10 to 50 seem, and more preferably 15 to 30 seem.

12. The method according to any one of claims 1 to 11 , further comprising the following step (A-2) between the step (A) and the step (B):(A-2) heating the film at a temperature of 50°C to 290°C, preferably 60°C to 270°C, more preferably 70°C to 250°C, and still more preferably 100°C to 200°C for 50 to 1 ,000 seconds, preferably 100 to 500 seconds, more preferably 120 to 300 seconds, and still more preferably 150 to 200 seconds.

13. The method according to any one of claims 1 to 12, further comprising the following step (C) after the step (B):(C) heating the film at a temperature of 300°C to 1 ,000°C, preferably 350°C to 950°C, more preferably 400°C to 900°C, and still more preferably 500°C to 850°C for 500 to 3,000 seconds, preferably 700 to 2,800 seconds, more preferably 900 to 2,500 seconds, and still more preferably 1 ,200 to 2,000 seconds.

14. The method according to any one of claims 1 to 13, wherein the polysilazane comprises a unit A represented by formula (1):[C1]Foreignfiling text P25-188 20260309whereinR1and R2are each independently a single bond, H, C1-10 alkyl, C2-10 alkenyl, C6-12 aryl, or a linking group represented by any one of formulas (a), (b), and (c); 5 preferably H, linear C1-10 alkyl, branched C3-10 alkyl, cyclic C3-10 alkyl, linear C2-10 alkenyl, branched C3-10 alkenyl, cyclic C3-10 alkenyl, C6-12 aryl, or a linking group represented by any one of formulas (a), (b), and (c); more preferably H, linear C1-5 alkyl, or a linking group represented by any one of formulas (a), (b), and (c); and still more preferably H, methyl, ethyl, n-propyl, isopropyl, or a linking group10 represented by any one of formulas (a), (b), and (c);one or more non-adjacent -CH2- groups in R1and R2may each independently be replaced with -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, or -C=C-;R1and R2are each independently, when being a single bond, bonded to N included in another unit represented by formula (1);R3is a single bond, H, C1-10 alkyl, C2-10 alkenyl, or C6-12 aryl; preferably H, linear Ci- 10 alkyl, branched C3-10 alkyl, cyclic C3-10 alkyl, linear C2-10 alkenyl, branched C3-10 alkenyl, cyclic C3-10 alkenyl, or C6-12 aryl; more preferably H or linear C1-5 alkyl; and still more preferably H, methyl, ethyl, n-propyl, or isopropyl;one or more non-adjacent -CH2- groups in R3may be replaced with -O-, -S-, - 20 CO-, -CO-O-, -O-CO-, -O-CO-O-, or -CEC-; andR3is, when being a single bond, bonded to Si contained in another unit represented by formula (1):[C2]Foreignfiling text P25-188 20260309( Ra)3-naa - s| —x zna1-nblr H '-2,p / Lbi\S[' 'nblCqHjq( RC%-nCl ( RC2)3-nc2(C)— L I_c i\ — g i - Q - g i - Z |_ c 2 \ -' 'ncl ' 'nc2whereinRa, Rc1, and Rc2are each independently H, C1-6 alkyl, C2-6 alkenyl, or C6-12 aryl; preferably H, linear C1-6 alkyl, branched C3-6 alkyl, cyclic C3-6 alkyl, linear C2-6 5 alkenyl, branched C3-6 alkenyl, cyclic C3-6 alkenyl, or C6-12 aryl; more preferably H or linear C1-5 alkyl; and still more preferably H, methyl, ethyl, n-propyl, or isopropyl;Rb1and Rb2are each independently H, C1-6 alkyl, C2-6 alkenyl, or C6-12 aryl; preferably H, linear C1-6 alkyl, branched C3-6 alkyl, cyclic C3-6 alkyl, linear C2-6 alkenyl, branched C3-6 alkenyl, cyclic C3-6 alkenyl, or C6-12 aryl; more preferably H or 10 linear C2-6 alkyl; and still more preferably H or vinyl;La, Lb1, Lb2, Lc1, and Lc2are each independently C1-8 alkylene, or Ce-14 arylene; preferably, linear C1-8 alkylene, branched C3-8 alkylene, or cyclic C3-8 alkylene, or Ce- 14 arylene; more preferably linear C1-5 alkylene; and still more preferably methylene, ethylene, or linear propylene;one or more non-adjacent -CH2- groups in La, Lb1, Lb2, Lc1, and Lc2may each independently be replaced with -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, - CH=CH-, or -C=C-;na is 1 to 3;nb1 and nb2 are each independently 1 to 2;20 nc1 and nc2 are each independently 1 to 3;p and q are each independently 1 to 3; andForeignfiling text P25-188 20260309- 38 -among the bonds in the linking groups of any one of formulas (a), (b), and (c), a bond which is not bonded to Si contained in a unit represented by formula (1) is bonded to Si contained in another unit represented by formula (1).

15. The method according to any one of claims 1 to 14, wherein the polysilazane further comprises a unit B represented by formula (2):[C3]whereinR4is H, C1-10 alkyl, C2-10 alkenyl, or C6-12 aryl; preferably H, linear C1-10 alkyl, branched C3-10 alkyl, cyclic C3-10 alkyl, linear C2-10 alkenyl, branched C3-10 alkenyl, cyclic C3-10 alkenyl, or C6-12 aryl; more preferably, H or linear C1-5 alkyl; and still more preferably H, methyl, ethyl, n-propyl, or isopropyl;one or more non-adjacent -CH2- groups in R4may each independently be replaced with -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, or -C=C-;one or more H atoms in R4may be replaced with -NH2, -N=C=O, or OH; n1 is 2, 3, or 4; andn2 is 4 - n1.

16. The method according to any one of claims 1 to 15, wherein the polysilazane comprises at least one end group represented by formula (3), preferably all end groups of the polysilazane are represented by formula (3):-SiR31R32R33(3)whereinR31, R32, and R33are each independently H, OH, C1-20 alkyl, C2-20 alkenyl, or Ce-20 aryl; preferably H, OH, linear C1-20 alkyl, branched C3-20 alkyl, cyclic C3-20 alkyl,Foreignfiling text P25-188 20260309- 39 -linear C2-20 alkenyl, branched C3-20 alkenyl, cyclic C3-20 alkenyl, or C6-20 aryl; more preferably, H, OH, linear C1-15 alkyl, or branched C3-15 alkyl; and still more preferably H, OH, linear C1-10 alkyl, or branched C3-10 alkyl; and even more preferably H, OH, or methyl;5 one or more non-adjacent -CH2- groups in R31, R32, and R33may each independently be replaced with -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, or - C=C-; andone or more H atoms in R31, R32, and R33may each independently be replaced with -OH, -COOH, or -SO2H.

17. The method according to claim 15, wherein a ratio of a number of units A to a number of units B in the polysilazane is 0.5 to 2, preferably 0.7 to 1.8, and more preferably 0.8 to 1.5.15

18. The method according to claim 15 or 17, wherein a ratio of a total number of units A and B to a number of end groups in the polysilazane is 1.2 to 2.5, preferably I .3 to 2.4, more preferably 1.4 to 2.0, and still more preferably 1.5 to 1.7.20

19. The method according to any one of claims 1 to 18, wherein the polysilazane has a mass-average molecular weight of 500 to 10,000, preferably 700 to 8,000, more preferably 900 to 6,000, and still more preferably 1 ,000 to 4,000.

20. The method according to any one of claims 1 to 19, wherein the composition further comprises a solvent.30

21. The method according to claim 20, wherein a solid component content of the composition is 30 to 75 mass%, preferably 35 to 70 mass%, more preferably 40 toForeignfiling_text_P25-188_2026030965 mass%, still more preferably 45 to 50 mass%, based on a total mass of the composition.

22. 5 A method for producing an electronic device, the method comprising the method according to any one of claims 1 to 21.

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