JP7101932B2 - Silicon-containing film forming composition for EUV lithography, silicon-containing film for EUV lithography and pattern forming method - Google Patents

Description

The present invention relates to a silicon-containing film forming composition for EUV lithography, a silicon-containing film for EUV lithography, and a pattern forming method.

In the manufacture of semiconductor devices, a multilayer resist process is used to obtain a high degree of integration. In this process, first, a silicon-containing film is formed on one surface side of the substrate using a composition for forming a silicon-containing film containing polysiloxane, and a resist is formed on the surface side of the silicon-containing film opposite to the substrate. A resist pattern is formed using the composition. Next, the silicon-containing film is etched using this resist pattern as a mask, and the substrate is further etched using the obtained silicon-containing film pattern as a mask to form a desired pattern on the substrate.

Recently, the integration of semiconductor devices has been further advanced, and the exposure light used has been shortened from KrF excimer laser (248 nm) and ArF excimer laser (193 nm) to extreme ultraviolet (13.5 nm, EUV). Tends to be.

Under these circumstances, as an EUV lithography application, such a silicon-containing film is made to contain an onium sulfonic acid salt (see International Publication No. 2014/021256).

International Publication No. 2014/021256

However, in EUV lithography, since the exposure is performed under vacuum, if the above-mentioned conventional composition for forming a silicon-containing film is used, a substance derived from the silicon-containing film is generated as outgas, and the projection of the EUV exposure apparatus is performed. Since the mirror, mask, and the like are contaminated, the resolving power of the EUV exposure apparatus deteriorates, and as a result, the resolving property of the resist pattern formed on the silicon-containing film is deteriorated.

The present invention has been made based on the above circumstances, and an object of the present invention is to form a silicon-containing film capable of forming a resist pattern having excellent outgas suppression properties, collapse suppression properties, and a good shape. It is an object of the present invention to provide a silicon-containing film forming composition for EUV lithography, a silicon-containing film for EUV lithography, and a pattern forming method.

The invention made to solve the above problems contains polysiloxane, a compound having an onium cation and a sulfonate anion, and a solvent, and the total atomic weight of the atoms constituting the sulfonate anion is 240 or more. A silicon-containing film-forming composition for EUV lithography, wherein the sulfonic acid anion has a sulfonate group and a carbon atom adjacent to the sulfonate group, and a fluorine atom is not bonded to the carbon atom.

Another invention made to solve the above problems is a silicon-containing film for EUV lithography formed from the silicon-containing film-forming composition for EUV lithography.

Yet another invention made to solve the above problems is a step of coating the silicon-containing film forming composition for EUV lithography on one surface side of the substrate, and a silicon-containing film formed by the coating step. Is a pattern forming method including a step of patterning.

According to the silicon-containing film forming composition for EUV lithography of the present invention, a silicon-containing film having excellent outgassing property can be formed, and such an excellent silicon-containing film can be used for a projection mirror, a mask, etc. of an EUV exposure apparatus. It is possible to prevent the contamination of silicon, and to form a resist pattern having excellent collapse suppressing property and a good shape. The silicon-containing film for EUV lithography of the present invention is excellent in outgas suppression property, and can form a resist pattern having good collapse suppression property and shape. According to the pattern forming method of the present invention, a desired substrate pattern having a good shape is formed by forming a silicon-containing film capable of forming a resist pattern having excellent outgas suppression property, collapse suppression property and good shape. can do. Therefore, these can be suitably used for EUV lithography, and can be suitably used for manufacturing semiconductor devices, which are expected to be further miniaturized in the future.

Hereinafter, the silicon-containing film forming composition for EUV lithography (hereinafter, simply referred to as “silicon-containing film forming composition”), the silicon-containing film for EUV lithography (hereinafter, simply referred to as “silicon-containing film”), and pattern formation of the present invention. Embodiments of the method will be described.

<Composition for forming a silicon-containing film>
The composition for forming a silicon-containing film includes polysiloxane (hereinafter, also referred to as "[A] polysiloxane"), onium cation (hereinafter, also referred to as "onium cation (X)"), and sulfonate anion (hereinafter, "". A compound having a sulfonic acid anion (Y) "(hereinafter, also referred to as" [B] compound ") and a solvent (hereinafter, also referred to as" [C] solvent ") are contained, and the sulfonic acid anion (hereinafter, also referred to as" [C] solvent ") is contained. The total atomic weight of the atoms constituting Y) is 240 or more, the sulfonate anion (Y) has a sulfonate group and a carbon atom adjacent to the sulfonate group, and a fluorine atom is bonded to this carbon atom. do not have.

The silicon-containing film-forming composition can form a silicon-containing film capable of forming a resist pattern having excellent outgas suppression property, collapse suppression property, and a good shape. Therefore, the silicon-containing film-forming composition can be suitably used for EUV lithography.

The composition for forming a silicon-containing film may contain an arbitrary component in addition to the [A] polysiloxane, the [B] compound and the [C] solvent as long as the effects of the present invention are not impaired. Hereinafter, each component will be described.

<[A] Polysiloxane>
[A] Polysiloxane is a polymer having a siloxane bond. [A] The polysiloxane has, for example, a structural unit (I) represented by the following formula (A), a structural unit (II) represented by the following formula (B), and the like. [A] The polysiloxane may have structural units other than the structural units (I) and (II) as long as the effects of the present invention are not impaired. Hereinafter, each structural unit will be described.

[Structural unit (I)]
The structural unit (I) is a structural unit represented by the following formula (A). In the composition for forming a silicon-containing film, various properties of the silicon-containing film can be adjusted by having [A] polysiloxane having a structural unit (I).

In the above formula ( ^A ), RA is a monovalent organic group having 1 to 20 carbon atoms. a is an integer of 1 to 3. When a is 2 or more, a plurality of ^RAs are the same or different.

Examples of the monovalent organic group represented by ^RA include a monovalent hydrocarbon group having 1 to 20 carbon atoms and a group having a divalent heteroatom-containing group between carbons of the hydrocarbon group (α). ), A group (β) in which a part or all of the hydrogen atom of the group (α) containing the above hydrocarbon group or the above divalent heteroatom-containing group is replaced with a monovalent heteroatom-containing group, and the like can be mentioned.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a carbon number of carbon atoms. Examples thereof include 6 to 20 monovalent aromatic hydrocarbon groups.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include alkanes such as methane, ethane, propane and butene, alkenes such as ethene, propene and butene, and alkynes such as ethine, propine and butene. Examples thereof include groups excluding one hydrogen atom.

Examples of monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms include alicyclic saturated hydrocarbons such as cycloalkanes such as cyclopentane and cyclohexane, and bridging ring saturated hydrocarbons such as norbornan, adamantan, and tricyclodecane. Examples thereof include groups excluding one hydrogen atom possessed by cycloalkenes such as hydrogen, cyclopentene and cyclohexene, and alicyclic unsaturated hydrocarbons such as bridging ring unsaturated hydrocarbons such as norbornene and tricyclodecene.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include hydrogens on 2 to 4 aromatic rings possessed by an arene such as benzene, toluene, ethylbenzene, xylene, naphthalene, methylnaphthalene, anthracene, and methylanthracene. Examples thereof include an atom or a group excluding a hydrogen atom on one aromatic ring and an alkyl group.

Examples of the hetero atom constituting the divalent and monovalent hetero atom-containing group include an oxygen atom, a nitrogen atom, a sulfur atom, a phosphorus atom, a silicon atom, a halogen atom and the like. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.

Examples of the divalent heteroatom-containing group include -O-, -CO-, -S-, -CS-, -NR'-, a group in which two or more of these are combined, and the like. R'is a hydrogen atom or a monovalent hydrocarbon group. Of these, —O— and —S— are preferred.

Examples of the monovalent hetero atom-containing group include halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom, hydroxy group, carboxy group, cyano group, amino group and sulfanyl group.

As ^RA , a monovalent chain hydrocarbon group, a monovalent aromatic hydrocarbon group, and a part or all of the hydrogen atoms of the monovalent hydrocarbon group were substituted with monovalent heteroatom-containing groups. Groups are preferred, alkyl groups and fluorine-substituted or unsubstituted aryl groups are more preferred, and methyl, phenyl and fluorophenyl groups are even more preferred.

When the [A] polysiloxane has the structural unit (I), the lower limit of the content ratio of the structural unit (I) is preferably 0.1 mol% with respect to all the structural units constituting the [A] polysiloxane. 1, 1 mol% is more preferable, 2 mol% is more preferable, 5 mol% is particularly preferable, and 8 mol% is even more preferable. The upper limit of the content ratio is preferably 80 mol%, more preferably 50 mol%, further preferably 30 mol%, and particularly preferably 20 mol%. By setting the content ratio of the structural unit (I) in the above range, various properties of the silicon-containing film can be further adjusted.

[Structural unit (II)]
The structural unit (II) is a structural unit represented by the following formula (B). In the composition for forming a silicon-containing film, since the [A] polysiloxane has a structural unit (II), the etching resistance of the silicon-containing film by an oxygen-based gas can be further enhanced.

Examples of the monomer giving the structural unit (II) include tetraalkoxysilanes such as tetramethoxysilane and tetraethoxysilane, and tetrahalosilanes such as tetrachlorosilane and tetrabromosilane.

When the [A] polysiloxane has the structural unit (II), the lower limit of the content ratio of the structural unit (II) is preferably 1 mol% with respect to all the structural units constituting the [A] polysiloxane. Mol% is more preferred, 30 mol% is even more preferred, and 60 mol% is particularly preferred. The upper limit of the content ratio is preferably 95 mol%, more preferably 90 mol%, further preferably 85 mol%, and particularly preferably 80 mol%. By setting the content ratio of the structural unit (II) in the above range in the composition for forming a silicon-containing film, the etching resistance of the silicon-containing film by an oxygen-based gas can be further enhanced.

[Other structural units]
Examples of other structural units include structural units derived from silane monomers containing a plurality of silicon atoms such as hexamethoxydisilane, bis (trimethoxysilyl) methane, and polydimethoxymethylcarbosilane. When the [A] polysiloxane has other structural units, the upper limit of the content ratio of the other structural units is preferably 10 mol% and 5 mol% with respect to all the structural units constituting the [A] polysiloxane. Is more preferable, 2 mol% is further preferable, and 1 mol% is particularly preferable.

[A] The lower limit of the content of the polysiloxane is preferably 50% by mass, more preferably 80% by mass, further preferably 90% by mass, and 95% by mass, based on the total solid content of the silicon-containing film-forming composition. Mass% is particularly preferred. The upper limit of the content is preferably 100% by mass, preferably 99% by mass, and more preferably 97% by mass. The total solid content of the silicon-containing film-forming composition is the sum of the components other than the [B] solvent. [A] Polysiloxane may contain only one type, or may contain two or more types.

[A] As the lower limit of the weight average molecular weight (Mw) of the polysiloxane, 1,000 is preferable, 1,300 is more preferable, 1,500 is further preferable, and 1,700 is particularly preferable. As the upper limit of the Mw, 100,000 is preferable, 20,000 is more preferable, 7,000 is further preferable, and 3,000 is particularly preferable.

For the Mw of [A] polysiloxane in the present specification, a GPC column (2 "G2000HXL", 1 "G3000HXL" and 1 "G4000HXL") manufactured by Tosoh Corporation is used, and the flow rate: 1.0 mL / min, elution. It is a value measured by gel permeation chromatography (detector: differential refractometer) using monodisperse polystyrene as a standard under analytical conditions of solvent: tetrahydrofuran and column temperature: 40 ° C.

[A] Polysiloxane can be obtained by a method of hydrolyzing and condensing a hydrolyzable silane monomer corresponding to each of the structural units described above. It is considered that each hydrolyzable silane monomer is incorporated into polysiloxane by the hydrolysis condensation reaction regardless of the type, and the structural units (I) and (II) and other structural units in the synthesized [A] polysiloxane are considered to be incorporated. The content ratio of is usually the same as the ratio of the amount of each monomer compound used in the synthesis reaction.

<[B] Compound>
The compound [B] is a compound having an onium cation (X) and a sulfonic acid anion (Y). In the compound [B], the onium cation (X) is decomposed to generate hydron (H ⁺ ) by irradiation and / or heating with radiation, and sulfonic acid is generated from this hydron and the sulfonic acid anion (Y). Hereinafter, the sulfonic acid anion (Y) and the onium cation (X) will be described.

[Sulfonic acid anion (Y)]
The sulfonic acid anion (Y) is an anion having a sulfonate group and a carbon atom adjacent to the sulfonate group, to which a fluorine atom is not bonded to the carbon atom. The sulfonic acid anion (Y) may be monovalent or divalent or higher, that is, it may have a plurality of sulfonate groups, but monovalent is preferable. When the sulfonic acid anion (Y) has a plurality of sulfonate groups, no fluorine atom is bonded to the carbon atom adjacent to the sulfonate group in any of the sulfonate groups.

The lower limit of the total atomic weight of the atoms constituting the sulfonic acid anion (Y) is 240, preferably 260, more preferably 290, still more preferably 330, particularly preferably 370, still more preferably 400, and 440. Most preferred. The upper limit of the total is, for example, 1000, preferably 600.

According to the silicon-containing film-forming composition, the volatility of the generated sulfonic acid can be reduced by setting the total atomic weight of the sulfonic acid anion (Y) to the above range, and as a result, the outgas suppression property can be reduced. Can be improved. Further, it is considered that this makes it possible to reduce contamination of the exposure system and the like in EUV lithography, so that the resist pattern can be suppressed from collapsing and the shape can be improved.

The monovalent sulfonic acid anion (Y) is represented by, for example, the following formula (1).

In the above formula (1), R ¹ is a monovalent organic group having 1 to 20 carbon atoms. R ² and R ³ are independently hydrogen atoms or methyl groups, or two or more of R ¹ , R ² and R ³ are composed of carbon atoms that are combined with each other and bonded to each other. Represents a ring structure having 3 to 20 ring members. The total atomic weight of the atoms constituting R ¹ , R ² and R ³ is 148 or more.

Examples of the monovalent organic group having 1 to 20 carbon atoms represented by R ¹ include the same groups as those exemplified as the monovalent organic group of ^RA in the above formula (A). As R ¹ , a group (β) containing -COO- between carbons of a monovalent alicyclic hydrocarbon group having 8 to 19 carbon atoms and a part of hydrogen atoms contained in this group (β) are used. A group substituted with a fluorine atom, a group (γ) in which a part or all of the hydrogen atoms of a monovalent chain hydrocarbon group having 1 to 20 carbon atoms are substituted with 7 or more fluorine atoms, and this group (γ). ) Is preferably a group in which a part of the hydrogen atom is substituted with a hydroxy group, a 1-cyclohexylcarbonyloxyethyl group, a 1-cyclohexylcarbonyloxy-2,2,2-trifluoroethyl group, and a 1-adamantyloxycarbonyl-2. , 2,2-Trifluoroethyl group, 2-perfluorohexyl-1-hydroxyethyl group and perfluoropropyl group are more preferable.

As R ² and R ³ , a hydrogen atom is preferable.

Examples of the ring structure having 3 to 20 ring members composed of two or more of R ¹ , R ² and R ³ include a cyclohexane structure, a cycloheptane structure, a cyclooctane structure, a cyclononan structure, a cyclodecane structure, and a cyclododecane structure. Monocyclic saturated alicyclic structure, cyclohexene structure, cycloheptene structure, cyclooctene structure, cyclodecene structure, etc., monocyclic unsaturated alicyclic structure, norbornan structure, adamantan structure, tricyclodecane structure, tetracyclododecane structure, etc. Alicyclic structures such as unsaturated bridged ring structures such as bridged ring structure, norbornene structure and tricyclodecene structure, aromatic carbocyclic structure such as benzene structure, naphthalene structure, phenanthrene structure and anthracene structure, hexanolactone structure, Oxygen atom-containing heterocyclic structure such as lactone structure such as norbornan lactone structure, hexanosulton structure, sulton structure such as norbornan sulton structure, oxacycloheptane structure, oxanorbornan structure, azacyclohexane structure, nitrogen such as diazabicyclooctane structure An aliphatic heterocyclic structure such as a sulfur atom-containing heterocyclic structure such as an atom-containing heterocyclic structure, a thiacyclohexane structure, and a thianolbornan structure, an oxygen atom-containing heterocyclic structure such as a pyran structure, a benzofuran structure, and a benzopyran structure, a pyridine structure, and a pyrimidine. Examples thereof include an aromatic heterocyclic structure such as a nitrogen atom-containing heterocyclic structure such as a structure and an indole structure. Among these, an alicyclic structure is preferable, a saturated crosslinked ring structure is more preferable, and a norbornane structure is further preferable.

Examples of the sulfonic acid anion (Y) include anions represented by the following formulas (Y-1) to (Y-6).

Among these, sulfonic acid anions (Y-2) to (Y-6) are preferable, and sulfonic acid anions (Y-3) to (Y-5) are more preferable.

[Onium cation (X)]
The onium cation (X) is a cation in which atoms such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, and Bi have a positive charge. Among these, S, I and N are preferable, and S and I are more preferable. The onium cation (X) may be monovalent or may contain a plurality of atoms having a divalent value or higher, that is, a positive charge, but monovalent is preferable.

Examples of the onium cation (X) include a sulfonium cation, an iodonium cation, an ammonium cation and the like.

Examples of the monovalent sulfonium cation include triphenyl-containing sulfonium cations such as triphenylsulfonium cation, 4-cyclohexylphenyldiphenylsulfonium cation, 4-t-butylphenyldiphenylsulfonium cation, and tri (4-t-butylphenyl) sulfonium cation. , 1- (4-n-butoxynaphthalene-1-yl) tetrahydrothiophenium cation, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium cation and other tetrahydrothiophenium cations. Be done.

Examples of the monovalent iodonium cation include diphenyl iodonium cation and bis (4-t-butylphenyl) iodonium cation.

Examples of the monovalent ammonium cation include tetramethylammonium cation, tetraethylammonium cation, and tetraphenylammonium cation.

Among these, sulfonium cations and iodonium cations are preferable, triphenyl-containing sulfonium cations and iodonium cations are more preferable, and triphenylsulfonium cations and diphenyliodonium cations are even more preferable.

As the lower limit of the content of the compound [B], 0.1 parts by mass is preferable, 0.5 parts by mass is more preferable, and 1 part by mass is more preferable, and 2 parts by mass is preferable with respect to 100 parts by mass of [A] polysiloxane. Part is particularly preferable. The upper limit of the content is preferably 30 parts by mass, more preferably 20 parts by mass, further preferably 10 parts by mass, and particularly preferably 5 parts by mass. By setting the content of the compound [B] in the above range, the outgas suppression property, the pattern collapse suppression property, and the goodness of the pattern shape can be further improved.

<[C] Solvent>
The solvent [C] is not particularly limited as long as it can dissolve or disperse the [A] polysiloxane, the [B] compound and any components contained as necessary. Examples of the [C] solvent include alcohol solvents, ketone solvents, ether solvents, ester solvents, nitrogen-containing solvents, water and the like. [C] The solvent may be used alone or in combination of two or more.

Examples of the alcohol solvent include monoalcohol solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol and iso-butanol, ethylene glycol, 1,2-propylene glycol, diethylene glycol and dipropylene glycol. Examples include polyhydric alcohol solvents.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-iso-butyl ketone, cyclohexanone and the like.

Examples of ether-based solvents include ethyl ether, iso-propyl ether, ethylene glycol dibutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol monopropyl ether. Examples thereof include tetrahydrofuran.

Examples of the ester solvent include ethyl acetate, γ-butyrolactone, n-butyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and acetic acid. Examples thereof include propylene glycol monoethyl ether, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, ethyl propionate, n-butyl propionate, methyl lactate, ethyl lactate and the like.

Examples of the nitrogen-containing solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone and the like.

Among these, an ether solvent, an ester solvent and water are preferable, and an ether solvent having a glycol structure and an ester solvent are more preferable because they are excellent in film forming property.

Examples of the ether solvent and ester solvent having a glycol structure include propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and propylene glycol monopropyl acetate. Examples include ether.

[C] The lower limit of the content of the ether solvent and the ester solvent having a glycol structure in the solvent is preferably 20% by mass, more preferably 60% by mass, further preferably 90% by mass, and particularly preferably 100% by mass. preferable.

The lower limit of the content of the [C] solvent in the silicon-containing film-forming composition is preferably 80% by mass, more preferably 90% by mass, and even more preferably 95% by mass. The upper limit of the content is preferably 99% by mass, more preferably 98% by mass.

<Arbitrary ingredient>
The silicon-containing film-forming composition may contain, for example, an acid generator, a surfactant, or the like as an optional component.

[Acid generator]
The acid generator is a compound that generates an acid by irradiation with ultraviolet light and / or heating. The acid generator may be used alone or in combination of two or more.

Examples of the acid generator include onium salt compounds, N-sulfonyloxyimide compounds and the like.

Examples of the onium salt compound include sulfonium salt, tetrahydrothiophenium salt, iodonium salt, ammonium salt and the like.

Examples of the sulfonium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate and the like.

Examples of the tetrahydrothiophenium salt include the tetrahydrothiophenium salt described in paragraph [0111] of JP-A-2014-037386, and more specifically, 1- (4-n-butoxynaphthalene-1-). Il) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalene-1-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalene-1-yl) Tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate and the like can be mentioned.

Examples of the iodonium salt include the iodonium salt described in paragraph [0112] of JP-A-2014-037386, and more specifically, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, and diphenyliodonium. Examples thereof include 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butane sulfonate and the like. ..

Examples of the ammonium salt include trimethylammonium nonafluoro-n-butane sulfonate, triethylammonium nonafluoro-n-butane sulfonate and the like.

Examples of the N-sulfonyloxyimide compound include the N-sulfonyloxyimide compound described in paragraph [0113] of JP-A-2014-037386, and more specifically, N- (trifluoromethanesulfonyloxy) bicyclo [ 2.2.1] Hept-5-en-2,3-dicarboxyimide, N- (nonafluoro-n-butanesulfonyloxy) bicyclo [2.2.1] Hept-5-en-2,3-di Carboximide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene- Examples thereof include 2,3-dicarboxyimide.

When the silicon-containing film-forming composition contains an acid generator, the lower limit of the content of the acid generator with respect to 100 parts by mass of [A] polysiloxane is preferably 0.01 parts by mass, preferably 0.1 parts by mass. % Is more preferable, 0.5 parts by mass is further preferable, and 1 part by mass is particularly preferable. As the upper limit of the content, 10 parts by mass is preferable, 5 parts by mass is more preferable, and 1 part by mass is further preferable.

When the silicon-containing film-forming composition contains any other component other than the acid generator, the upper limit of the content is preferably 1 part by mass and 0 parts by mass with respect to 100 parts by mass of [A] polysiloxane. 5.5 parts by mass is more preferable, and 0.1 parts by mass is further preferable.

<Method of preparing a composition for forming a silicon-containing film>
The method for preparing the silicon-containing film-forming composition is not particularly limited, and for example, [A] polysiloxane, [B] compound, [C] solvent and, if necessary, an arbitrary component are mixed in a predetermined ratio, preferably. , The obtained mixed solution can be prepared by filtering with a filter having a pore size of 0.2 μm.

The lower limit of the solid content concentration of the silicon-containing film-forming composition is preferably 0.01% by mass, more preferably 0.05% by mass, further preferably 0.1% by mass, and particularly 0.2% by mass. preferable. The upper limit of the solid content concentration is preferably 20% by mass, more preferably 10% by mass, further preferably 5% by mass, and particularly preferably 3% by mass. The solid content concentration of the silicon-containing film-forming composition is obtained by measuring the mass of the solid content in the silicon-containing film-forming composition by firing the silicon-containing film-forming composition at 250 ° C. for 30 minutes. It is a value (mass%) calculated by dividing the mass of the solid content by the mass of the silicon-containing film-forming composition.

<Silicon-containing film>
The silicon-containing film of the present invention is formed from the silicon-containing film-forming composition. Since the silicon-containing film is formed from the above-mentioned composition for forming a silicon-containing film, it is possible to form a resist pattern having excellent outgas suppression property, collapse suppression property, and good shape.

The silicon-containing film is formed by applying the above-mentioned silicon-containing film-forming composition to the surface of another underlayer film such as a substrate or an organic underlayer film to form a coating film, and the coating film is heat-treated. It can be formed by curing.

Examples of the method for applying the silicon-containing film-forming composition include a rotary coating method, a roll coating method, and a dip method. As the lower limit of the temperature of the heat treatment, 50 ° C. is preferable, and 70 ° C. is more preferable. The upper limit of the temperature is preferably 450 ° C., more preferably 300 ° C. The lower limit of the average thickness of the silicon-containing film formed is preferably 5 nm, more preferably 10 nm. The upper limit of the average thickness is preferably 50 nm, more preferably 20 nm, and even more preferably 15 nm.

<Pattern formation method>
The pattern forming method includes a step of coating the silicon-containing film forming composition on one surface side of the substrate (hereinafter, also referred to as “coating step”) and a silicon-containing film formed by the coating step. (Hereinafter, also referred to as “silicon-containing film patterning step”).

According to the pattern forming method, a silicon-containing film capable of forming a resist pattern having excellent outgas suppression property, collapse suppression property and good shape is formed, and such an excellent silicon-containing film has a good shape. The desired substrate pattern can be formed.

In the silicon-containing film patterning step, the resist composition is applied to the surface side of the silicon-containing film opposite to the substrate, and the resist film formed by the resist composition coating step is subjected to extreme ultraviolet rays. The step of exposing and the step of developing the exposed resist film,
A step of etching the silicon-containing film using the resist pattern formed by the development step as a mask (hereinafter, also referred to as a “silicon-containing film etching step”) may be provided. By further providing such a step, a resist pattern having a good collapse suppressing property and a good shape can be formed by the silicon-containing film having an excellent outgas suppressing property, and as a result, a desired substrate pattern having a better shape can be formed. Can be formed.

The pattern forming method further includes, if necessary, a step of forming an organic underlayer film on at least one surface side of the substrate (hereinafter, also referred to as "organic underlayer film forming step") before the coating step. You may. The pattern forming method usually includes, after the silicon-containing film patterning step, a step of etching a substrate using the patterned silicon-containing film as a mask (hereinafter, also referred to as a “planet etching step”). Hereinafter, each step will be described.

<Organic underlayer film forming process>
In this step, an organic underlayer film is formed on at least one surface side of the substrate. In the pattern forming method, an organic underlayer film forming step can be performed, if necessary.

When the organic underlayer film forming step is performed in the pattern forming method, the above coating step is performed after the organic underlayer film forming step, and in this coating step, the silicon-containing film forming composition is used on the organic underlayer film. To form a silicon-containing film.

Examples of the substrate include an insulating film such as silicon oxide, silicon nitride, silicon oxynitride, and polysiloxane, and a resin substrate. For example, an interlayer insulating film such as a wafer coated with a low dielectric insulating film formed of "Black Diamond" of AMAT, "Silk" of Dow Chemical, "LKD5109" of JSR, etc. can be used. As this substrate, a patterned substrate such as a wiring groove (trench) and a plug groove (via) may be used.

The organic underlayer film is different from the silicon-containing film formed from the silicon-containing film-forming composition. The organic underlayer film has a predetermined function (for example, antireflection) required to further supplement the function of the silicon-containing film and / or the resist film in resist pattern formation and to obtain a function that these films do not have. It is a film that imparts properties, flatness of the coating film, and high etching resistance to fluorine-based gas).

Examples of the organic underlayer film include an antireflection film and the like. Examples of the antireflection film forming composition include "NFC HM8006" manufactured by JSR Corporation.

The organic underlayer film can be formed by applying a composition for forming an organic underlayer film by a rotary coating method or the like to form a coating film, and then heating the film.

<Coating process>
In this step, the silicon-containing film-forming composition is applied to one surface side of the substrate. By this step, a silicon-containing film is formed on the substrate directly or through another layer such as an organic underlayer film.

The coating method of the silicon-containing film-forming composition is not particularly limited, and examples thereof include a method of coating the silicon-containing film-forming composition on a substrate or the like by a known method such as a rotary coating method. A silicon-containing film is formed by curing the coating film formed by this coating process by exposing and / or heating as necessary.

Examples of the radiation used for this exposure include electromagnetic waves such as visible light, ultraviolet rays, far ultraviolet rays, X-rays and γ-rays, and particle beams such as electron beams, molecular beams and ion beams.

The lower limit of the temperature at which the coating film is heated is preferably 90 ° C, more preferably 150 ° C, and even more preferably 200 ° C. The upper limit of the temperature is preferably 550 ° C, more preferably 450 ° C, and even more preferably 300 ° C. The lower limit of the average thickness of the silicon-containing film formed is preferably 1 nm, more preferably 10 nm, and even more preferably 20 nm. The upper limit of the average thickness is preferably 20,000 nm, more preferably 1,000 nm, and even more preferably 100 nm.

<Silicon-containing film patterning process>
In this step, the silicon-containing film formed by the above coating step is patterned. By this step, the silicon-containing film formed in the above coating step is patterned. Examples of the method for patterning the silicon-containing film include a step of forming a resist pattern on the surface side of the silicon-containing film opposite to the substrate (hereinafter, also referred to as “resist pattern forming step”) and a silicon-containing film etching step. And the like.

[Resist pattern forming process]
In this step, a resist pattern is formed on the surface side of the silicon-containing film opposite to the substrate. Examples of the method for forming the resist pattern include conventionally known methods such as a method using a resist composition and a method using a nanoimprint lithography method. This resist pattern is usually formed from an organic material.

As a method of using the resist composition, for example, a step of applying the resist composition to the surface side of the silicon-containing film opposite to the substrate by the resist composition (hereinafter, also referred to as “resist composition coating step”). A method including a step of exposing the resist film (hereinafter, also referred to as “exposure step”) and a step of developing the exposed resist film (hereinafter, also referred to as “development step”) can be mentioned.

(Resist composition coating process)
In this step, the resist composition is applied to the surface side of the silicon-containing film opposite to the substrate by the resist composition.

Examples of the resist composition include a polymer having an acid dissociative group, a radiation-sensitive resin composition containing a radiation-sensitive acid generator (chemically amplified resist composition), an alkali-soluble resin, and a quinonediazide-based photosensitizer. Examples thereof include a positive resist composition, a negative resist composition containing an alkali-soluble resin and a cross-linking agent, and the like. Among these, a radiation-sensitive resin composition is preferable. When a radiation-sensitive resin composition is used, a positive pattern can be formed by developing with an alkaline developer, and a negative pattern can be formed by developing with an organic solvent developer. For forming the resist pattern, a double patterning method, a double exposure method, or the like, which is a method for forming a fine pattern, may be appropriately used.

The polymer contained in the radiation-sensitive resin composition includes, for example, a structural unit containing a lactone structure, a cyclic carbonate structure and / or a sulton structure, and a structural unit containing an alcoholic hydroxyl group, in addition to the structural unit containing an acid dissociative group. , A structural unit containing a phenolic hydroxyl group, a structural unit containing a fluorine atom, or the like. When the polymer has a structural unit containing a phenolic hydroxyl group and / or a structural unit containing a fluorine atom, the sensitivity when extreme ultraviolet (EUV), electron beam, or the like is used as radiation in exposure can be improved.

The lower limit of the solid content concentration of the resist composition is preferably 0.1% by mass, preferably 1% by mass. The upper limit of the solid content concentration is preferably 50% by mass, more preferably 30% by mass. As the resist composition, one filtered using a filter having a pore size of about 0.2 μm can be preferably used. In the pattern forming method, a commercially available resist composition can be used as it is as the resist composition.

Examples of the method for forming the resist film include a method of applying a resist composition onto a silicon-containing film. Examples of the method for applying the resist composition include conventional methods such as a rotary coating method. When applying the resist composition, the amount of the resist composition to be applied is adjusted so that the obtained resist film has a predetermined film thickness.

The resist film can be formed by volatilizing the solvent in the coating film by prebaking the coating film of the resist composition. The prebake temperature is appropriately adjusted according to the type of resist composition used and the like, but the lower limit of the prebake temperature is preferably 30 ° C., more preferably 50 ° C. The upper limit of the temperature is preferably 200 ° C., more preferably 150 ° C.

(Exposure process)
In this step, the resist film is exposed. This exposure is performed by selectively irradiating radiation with, for example, a mask.

EUV or electron beam is preferable as the radiation used for exposure.

(Development process)
In this step, the exposed resist film is developed. As a result, a resist pattern is formed.

The development may be alkaline development or organic solvent development.

Examples of the alkaline developing solution include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine and dimethylethanol. Amine, triethanolamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3. 0] An alkaline aqueous solution such as -5-nonene can be mentioned. Further, these alkaline aqueous solutions may be prepared by adding an appropriate amount of a water-soluble organic solvent such as alcohols such as methanol and ethanol, and a surfactant.

Examples of the organic solvent developing solution include a solution containing an organic solvent as a main component, such as a ketone solvent, an alcohol solvent, an amide solvent, an ether solvent, and an ester solvent. Examples of these solvents include the same solvents as those exemplified as the above-mentioned [B] solvent. These solvents may be used alone or in combination of two or more.

After developing with a developing solution, preferably, it is washed and dried to form a predetermined resist pattern corresponding to the photomask.

[Silicon-containing film etching process]
In this step, the silicon-containing film is etched using the resist pattern as a mask. More specifically, a silicon-containing film in which a pattern is formed is obtained by one or a plurality of etchings using the resist pattern formed in the resist pattern forming step as a mask.

The etching may be dry etching or wet etching, but dry etching is preferable.

Dry etching can be performed using, for example, a known dry etching apparatus. The etching gas used for dry etching can be appropriately selected depending on the elemental composition of the silicon-containing film to be etched, for example, CHF ₃ , CF ₄ , C ₂ F ₆ , C ₃ F ₈ , SF ₆ , and the like. Fluorine gas, chlorine gas such as Cl ₂ , BCl ₃ , oxygen gas such as O ₂ , O ₃ , H ₂ O, H ₂ , NH ₃ , CO, CO ₂ , CH ₄ , C ₂ H ₂ , C Reducing gases such as ₂ H ₄ , C ₂ H ₆ , C ₃ H ₄ , C ₃ H ₆ , C ₃ H ₈ , HF, HI, HBr, HCl, NO, NH ₃ , BCl ₃ , He, N ₂ , An inert gas such as Ar is used. These gases can also be mixed and used. A fluorine-based gas is usually used for dry etching of the silicon-containing film, and a mixture of an oxygen-based gas and an inert gas is preferably used.

<Substrate etching process>
In this step, the substrate is etched using the patterned silicon-containing film as a mask. More specifically, a patterned substrate is obtained by performing one or a plurality of times of etching using the pattern formed on the silicon-containing film obtained in the above-mentioned silicon-containing film etching step as a mask.

When an organic underlayer film is formed on a substrate, a pattern of the organic underlayer film is formed by etching the organic underlayer film using the silicon-containing film pattern as a mask, and then the substrate is etched using this organic underlayer film pattern as a mask. As a result, a pattern is formed on the substrate.

The etching may be dry etching or wet etching, but dry etching is preferable.

Dry etching when forming a pattern on the organic underlayer film can be performed using a known dry etching apparatus. The etching gas used for dry etching can be appropriately selected depending on the elemental composition of the silicon-containing film and the organic underlayer film to be etched. For example, CHF ₃ , CF ₄ , C ₂ F ₆ , C ₃ F ₈ , Fluorine gas such as SF ₆ , chlorine gas such as Cl ₂ , BCl ₃ , oxygen gas such as O ₂ , O ₃ , H ₂ O, H ₂ , NH ₃ , CO, CO ₂ , CH ₄ , C Reducing gases such as ₂ H ₂ , C ₂ H ₄ , C ₂ H ₆ , C ₃ H ₄ , C ₃ H ₆ , C ₃ H ₈ , HF, HI, HBr, HCl, NO, NH ₃ , BCl ₃ , etc. Inactive gases such as He, _N2 , and Ar are used, and these gases can be mixed and used. An oxygen-based gas is usually used for dry etching of an organic underlayer film using a silicon-containing film pattern as a mask.

Dry etching when forming a pattern on a substrate using the organic underlayer film pattern as a mask can be performed using a known dry etching apparatus. The etching gas used for dry etching can be appropriately selected depending on the elemental composition of the organic underlayer film and the substrate to be etched, and is the same as that exemplified as the etching gas used for dry etching of the organic underlayer film, for example. Etching gas and the like. Etching may be performed with a plurality of different etching gases. If the silicon-containing film remains on the substrate, the resist lower layer pattern, or the like after the substrate pattern forming step, the silicon-containing film can be removed by performing the silicon-containing film removing step described later. ..

Hereinafter, examples will be described. In addition, the examples shown below show an example of a typical example of the present invention, and the scope of the present invention is not narrowly interpreted by this.

The solid content concentration in the solution of [A] polysiloxane and the weight average molecular weight (Mw) of [A] polysiloxane in this example were measured by the following methods.

[[A] Solid content concentration of polysiloxane solution]
By firing 0.5 g of the solution of [A] polysiloxane at 250 ° C. for 30 minutes, the mass of the solid content in 0.5 g of this solution was measured, and the solid content concentration (mass%) of the solution of [A] polysiloxane was measured. ) Was calculated.

[Weight average molecular weight (Mw)]
Using a GPC column (2 "G2000HXL", 1 "G3000HXL", 1 "G4000HXL" from Tosoh Corporation), flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, column temperature: 40 ° C. under analytical conditions. , Measured by gel permeation chromatography (detector: differential refractometer) using monodisperse polystyrene as a standard.

<[A] Synthesis of polysiloxane>
[A] The monomers used for the synthesis of polysiloxane are shown below.
In the following synthesis examples, unless otherwise specified, the mass part means a value when the total mass of the used monomers is 100 parts by mass.
Compounds (M-1) to (M-4): Compounds represented by the following formulas (M-1) to (M-4)

[Synthesis Example 1-1] (Synthesis of Polysiloxane (A-1))
In the reaction vessel, 62 mass of propylene glycol monoethyl ether so that the molar ratio of the compound represented by the above formula (M-1) and the compound represented by the above formula (M-2) is 90/10 (mol%). A monomer solution was prepared by dissolving in the part. The temperature inside the reaction vessel was set to 60 ° C., and 40 parts by mass of a 9.1 mass% oxalic acid aqueous solution was added dropwise over 20 minutes while stirring. The start of dropping was set as the start time of the reaction, and the reaction was carried out for 4 hours. After completion of the reaction, the inside of the reaction vessel was cooled to 30 ° C. or lower. After adding 52 parts by mass of propylene glycol monoethyl ether to the cooled reaction solution, water, alcohols produced by the reaction and excess propylene glycol monoethyl ether are removed using an evaporator to remove polysiloxane (A-1). ) Was obtained. The Mw of polysiloxane (A-1) was 1,950. The solid content concentration of the propylene glycol monoethyl ether solution of this polysiloxane (A-1) was 12.0% by mass.

[Synthesis Examples 1-2 to 1-4] (Synthesis of Polysiloxanes (A-2) to (A-4))
Propylene glycol monoethyl ether solutions of polysiloxanes (A-2) to (A-4) were obtained in the same manner as in Synthesis Example 1 except that the monomers of the types and amounts shown in Table 1 below were used. rice field. The Mw and solid content concentration (mass%) of the [A] polysiloxane in the obtained solution of the [A] polysiloxane are also shown in Table 1. “-” In Table 1 indicates that the corresponding monomer was not used.

<Preparation of composition for forming silicon-containing film>
The components other than [A] polysiloxane used for preparing the composition for forming a silicon-containing film are shown below.

[[B] Compound]
Examples: B-1 to B-8: Compounds represented by the following formulas (B-1) to (B-8) Comparative examples: b-1 to b-3: The following formulas (b-1) to (b) Compound represented by -3)

The total atomic weights of the atoms constituting the sulfonic acid anion are 249 for (B-1), 263 for (B-2), 303 for (B-3), 303 for (B-4), and (B-). 5) is 355, (B-6) is 428, (B-7) is 428, (B-8) is 459, (b-1) is 231 and (b-2) is 323, (b-3). Is 318.

[[C] Solvent]
C-1: Propylene glycol monoethyl ether acetate C-2: Propylene glycol monoethyl ether C-3: Water

[Example 1-1]
[A] 0.59 parts by mass of (A-1) as a polysiloxane (solid content), 0.10 parts by mass of (B-1) as a [B] compound, and (C-1) as a solvent. ) 10 parts by mass, (C-2) 86 parts by mass (including the solvent (C-2) contained in the solution of [A] polysiloxane) and (C-3) 4 parts by mass were mixed and obtained. The solution was filtered through a filter having a pore size of 0.2 μm to prepare a silicon-containing film-forming composition (J-1).

[Examples 1-2 to 1-11 and Comparative Examples 1-1 to 1-3]
The silicon-containing film-forming compositions (J-2) to (J-11) and (j-1) are the same as in Example 1 except that the components of the types and blending amounts shown in Table 2 below are used. -(J-3) was prepared.

<Formation of silicon-containing film>
Each of the prepared silicon-containing film-forming compositions was coated on a silicon wafer (substrate) by a rotary coating method using a spin coater (“CLEAN TRACK ACT12” manufactured by Tokyo Electron Limited). The obtained coating film was heated on a hot plate at 220 ° C. for 60 seconds and then cooled at 23 ° C. for 60 seconds to form Examples 1-1 to 1-11 and Comparative Examples 1-1 to 1 in Table 2. A substrate on which a silicon-containing film having an average thickness of 13 nm shown in -3 was formed was obtained.

<Evaluation>
The following items of the prepared silicon-containing film forming composition and the formed silicon-containing film were evaluated by the following methods. The evaluation results are shown in Table 2 below.

[Outgas inhibitory]
Each of the prepared silicon-containing film-forming compositions was coated on an 8-inch silicon wafer (substrate) by a rotary coating method using a spin coater (“CLEAN TRACK ACT8” manufactured by Tokyo Electron Limited). The obtained coating film was heated on a hot plate at 220 ° C. for 60 seconds and then cooled at 23 ° C. for 60 seconds to obtain a substrate on which a silicon-containing film having an average thickness of 13 nm was formed. Then, using a hot plate in which an 8-inch silicon wafer was placed on the top plate of the hot plate, the mixture was heated at 300 ° C. for 60 seconds. After repeating the above process 50 times, the 8-inch silicon wafer placed on the top plate of the hot plate was washed with cyclohexanone to recover the sublimated material deposited on the substrate. Outgas inhibitory properties are "A" (good) when the amount of sublimated substance is 1.0 mg or less, "B" (slightly good) when the amount of sublimated substance is more than 1.0 mg and 2.0 mg or less, and when it exceeds 2.0 mg. Was evaluated as "C" (defective).

[Collapse suppression property] (Collapse suppression property of positive resist pattern in electron beam exposure or extreme ultraviolet exposure)
An antireflection film forming material (JSR's "HM8006") is applied onto an 8-inch silicon wafer by the rotary coating method using the spin coater, and then heated at 250 ° C. for 60 seconds to prevent reflection with an average thickness of 100 nm. A film was formed. A silicon-containing film-forming composition was applied onto the antireflection film, heated at 220 ° C. for 60 seconds, and then cooled at 23 ° C. for 30 seconds to form a silicon-containing film having an average thickness of 13 nm.
Next, a radiation-sensitive resin composition described later is applied onto the formed silicon-containing film, heat-treated at 130 ° C. for 60 seconds, and then cooled at 23 ° C. for 30 seconds to obtain a resist film having an average thickness of 50 nm. Was formed.

The radiation-sensitive resin composition includes a structural unit (1) derived from 4-hydroxystyrene, a structural unit (2) derived from styrene, and a structural unit (3) derived from 4-t-butoxystyrene (each structural unit). The content ratio of is 100 parts by mass of the polymer having (1) / (2) / (3) = 65/5/30 (mol%)) and triphenylsulfonium salicylate as a radiation-sensitive acid generator. It was obtained by mixing 2.5 parts by mass, 1,500 parts by mass of ethyl lactate as a solvent and 700 parts by mass of propylene glycol monomethyl ether acetate, and filtering the obtained solution with a filter having a pore size of 0.2 μm.

In the case of electron beam exposure, the resist film was irradiated with an electron beam using an electron beam drawing apparatus (“HL800D” manufactured by Hitachi, Ltd., output: 50 KeV, current density: 5.0 amperes / cm ² ). After irradiation with the electron beam, the substrate was heated at 110 ° C. for 60 seconds and then cooled at 23 ° C. for 60 seconds. Then, using a 2.38 mass% TMAH aqueous solution (20 to 25 ° C.), the substrate was developed by the paddle method, washed with water, and dried to obtain an evaluation substrate on which a resist pattern was formed. When forming the resist pattern, the exposure amount formed in a one-to-one line and space with a line width of 150 nm was taken as the optimum exposure amount. A scanning electron microscope (“CG-4000” manufactured by Hitachi High-Technologies Corporation) was used for measuring and observing the resist pattern of the evaluation substrate. The collapse inhibitory property was evaluated as "A" (good) when pattern collapse was not confirmed and as "B" (poor) when pattern collapse was confirmed at the above optimum exposure amount.

For extreme UV exposure, EUV scanner (ASML's "TWINSCAN NXE: 3300B" (NA0.3, Sigma 0.9, Quadrupole lighting, one-to-one line-and-space mask with a line width of 25 nm on the wafer) After the exposure, the substrate was heated at 110 ° C. for 60 seconds and then cooled at 23 ° C. for 60 seconds. Then, a 2.38 mass% TMAH aqueous solution (20 to 25 ° C.) was used. Was developed by the paddle method, washed with water, and dried to obtain an evaluation substrate on which a resist pattern was formed. At the time of forming the resist pattern, a 1: 1 line and space having a line width of 25 nm was obtained. The optimum exposure amount was used as the optimum exposure amount. A scanning electron microscope (“CG-4000” manufactured by Hitachi High-Technologies Co., Ltd.) was used for measuring and observing the resist pattern of the evaluation substrate. Was evaluated as "A" (good) when pattern collapse was not confirmed and as "B" (poor) when pattern collapse was confirmed at the above optimum exposure amount.

[Pattern shape]
In the shape of the resist pattern, when there was no hemming, it was evaluated as "A" (good), and when there was hemming, it was evaluated as "B" (poor).

As can be seen from the results in Table 2, according to the silicon-containing film-forming composition of the example, a silicon-containing film having excellent outgas suppression property can be formed, and such an excellent silicon-containing film suppresses collapse. A resist pattern having good properties and shape can be formed.

According to the silicon-containing film forming composition for EUV lithography of the present invention, a silicon-containing film having excellent outgassing property can be formed, and such an excellent silicon-containing film can be used for a projection mirror, a mask, etc. of an EUV exposure apparatus. It is possible to prevent the contamination of silicon, and to form a resist pattern having excellent collapse suppressing property and a good shape. The silicon-containing film for EUV lithography of the present invention is excellent in outgas suppression property, and can form a resist pattern having good collapse suppression property and shape. According to the pattern forming method of the present invention, a desired substrate pattern having a good shape is formed by forming a silicon-containing film capable of forming a resist pattern having excellent outgas suppression property, collapse suppression property and good shape. can do. Therefore, these can be suitably used for EUV lithography, and can be suitably used for manufacturing semiconductor devices and the like, which are expected to be further miniaturized in the future.

Claims (8)

With polysiloxane,
Compounds with onium cations and sulfonic acid anions,
With solvent
Contains,
The total atomic weight of the atoms constituting the sulfonic acid anion is 240 or more.
The sulfonic acid anion has a sulfonate group and a carbon atom adjacent to the sulfonate group.
Fluorine atom is not bonded to this carbon atom,
The sulfonic acid anion is represented by the following formula (1).,
The polysiloxane has a structural unit represented by the following formula (B) and has a structural unit.
The content ratio of the structural unit represented by the above formula (B) to all the structural units constituting the polysiloxane is 10 mol% or more. Silicon-containing film forming composition for EUV lithography.

In the above formula (1), R¹Is a monovalent organic group having 1 to 20 carbon atoms, and R²And R³Are each independently a hydrogen atom or a methyl group, or R¹, R²And R³Two or more of them represent an alicyclic structure having 3 to 20 ring members, which is composed of carbon atoms that are combined with each other and bonded to each other. R¹, R²And R³The total atomic weight of the atoms constituting the above is 148 or more.

The silicon-containing film forming composition for EUV lithography according to claim 1, wherein the content of the compound having an onium cation and a sulfonic acid anion is 0.1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the polysiloxane. thing. The silicon-containing film-forming composition for EUV lithography according to claim 1 or 2 , wherein the total atomic weights of the atoms constituting the sulfonic acid anion are 290 or more. The silicon-containing film-forming composition for EUV lithography according to any one of claims 1 to 3 , wherein the onium cation is a sulfonium cation, an iodonium cation, or a combination thereof. A silicon-containing film for EUV lithography formed from the silicon-containing film-forming composition for EUV lithography according to any one of claims 1 to 4 . A step of applying the silicon-containing film-forming composition for EUV lithography according to any one of claims 1 to 5 on one surface side of the substrate.
A pattern forming method including a step of patterning a silicon-containing film formed by the above coating step. The silicon-containing film patterning step
The step of applying the resist composition to the surface side of the silicon-containing film opposite to the substrate, and
A step of exposing the resist film formed by the resist composition coating step with extreme ultraviolet rays, and a step of exposing the resist film to extreme ultraviolet rays.
The process of developing the exposed resist film and
The pattern forming method according to claim 6 , further comprising a step of etching the silicon-containing film using the resist pattern formed by the developing step as a mask. Before the above coating process,
The pattern forming method according to claim 6 or 7 , further comprising a step of forming an organic underlayer film on at least one surface side of the substrate.