WO2016140057A1 - Radiation-sensitive composition and pattern formation method - Google Patents

Abstract

The present invention is a radiation-sensitive composition containing a polymer having a first structural unit containing an acid-dissociable group, a radiation-sensitive acid generator, and a compound represented by the following formula (1). In formula (1), M is a metal atom. L is a ligand other than OR¹. R¹ is a C1-20 hydrocarbon group. x is an integer of 0-5. y is an integer of 1-6. x + y is 6 or less. If x is 2 or greater, the plurality of Ls may be identical or different. If y is 2 or greater, the plurality of R¹s may be identical or different.

Description

Radiation-sensitive composition and pattern forming method

The present invention relates to a radiation-sensitive composition and a pattern forming method.

Radiation sensitive compositions used for microfabrication by lithography are exposed to irradiated parts such as deep ultraviolet rays such as ArF excimer laser light and KrF excimer laser light, electromagnetic waves such as extreme ultraviolet rays (EUV), and charged particle beams such as electron beams. An acid is generated in the substrate, and a chemical reaction using the acid as a catalyst causes a difference in the dissolution rate of the exposed portion and the unexposed portion in the developer, thereby forming a pattern on the substrate.

Such a radiation-sensitive composition is required to improve resist performance as the processing technique becomes finer. In response to this requirement, the types and molecular structures of polymers, acid generators and other components used in the composition have been studied, and further their combinations have been studied in detail (Japanese Patent Application Laid-Open No. 11-125907, special features). (See Kaihei 8-146610 and JP-A 2000-298347).

At present, pattern miniaturization has progressed to a level of 40 nm or less, but the radiation-sensitive composition has excellent resist performance, particularly electron beam, EUV, etc. while maintaining excellent storage stability. In addition to high sensitivity to exposure light, it is also required that the nano-edge roughness of the pattern be smaller, and it is also required to achieve a smaller limit resolution. However, not all of these requirements can be met.

JP-A-11-125907 JP-A-8-146610 JP 2000-298347 A

The present invention has been made based on the circumstances as described above, and its object is to provide a radiation-sensitive composition and a pattern forming method that are excellent in sensitivity, nanoedge roughness performance, storage stability, and limit resolution. There is.

（式（１）中、Ｍは、金属原子である。Ｌは、ＯＲ^１以外の配位子である。Ｒ^１は、炭素数１～２０の１価の炭化水素基である。ｘは、０～５の整数である。ｙは、１～６の整数である。但し、ｘ＋ｙは６以下である。ｘが２以上の場合、複数のＬは同一でも異なっていてもよい。ｙが２以上の場合、複数のＲ^１は同一でも異なっていてもよい。） The invention made in order to solve the above-mentioned problem is a polymer having a first structural unit (hereinafter also referred to as “structural unit (I)”) containing an acid dissociable group (hereinafter referred to as “[A] polymer”). A radiation sensitive acid generator (hereinafter also referred to as “[B] acid generator”), and a compound represented by the following formula (1) (hereinafter also referred to as “[C] compound”). It is a radiation sensitive composition.

(In Formula (1), M is a metal atom. L is a ligand other than OR ^1. R ¹ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. X is Y is an integer of 0 to 5. y is an integer of 1 to 6. However, x + y is not more than 6. When x is 2 or more, a plurality of L may be the same or different. In the above case, the plurality of R ¹ may be the same or different.)

Another invention made to solve the above-mentioned problems comprises a step of forming a film, a step of exposing the film, and a step of developing the exposed film, and the film is made of the radiation-sensitive composition. This is a pattern forming method to be formed.

Here, the “acid-dissociable group” refers to a group that replaces a hydrogen atom such as a carboxy group, a sulfo group, or a phenolic hydroxyl group, and dissociates by the action of an acid. The “hydrocarbon group” includes a chain hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. The “hydrocarbon group” may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The “chain hydrocarbon group” refers to a hydrocarbon group that does not include a cyclic structure but includes only a chain structure, and includes both a linear hydrocarbon group and a branched hydrocarbon group. The term “alicyclic hydrocarbon group” refers to a hydrocarbon group that includes only an alicyclic structure as a ring structure and does not include an aromatic ring structure, and includes a monocyclic alicyclic hydrocarbon group and a polycyclic alicyclic group. Includes both hydrocarbon groups. However, it is not necessary to be composed only of the alicyclic structure, and a part thereof may include a chain structure. “Aromatic hydrocarbon group” refers to a hydrocarbon group containing an aromatic ring structure as a ring structure. However, it is not necessary to be composed only of an aromatic ring structure, and a part thereof may include a chain structure or an alicyclic structure. “Number of ring members” means the number of atoms constituting the ring of the alicyclic structure, aromatic ring structure, aliphatic heterocyclic structure and aromatic heterocyclic structure, and in the case of polycyclic, the number of atoms constituting this polycyclic ring Say.

According to the radiation-sensitive composition and pattern formation method of the present invention, it is possible to form a pattern with small nanoedge roughness and excellent limit resolution while improving sensitivity and storage stability. Therefore, these can be suitably used for manufacturing semiconductor devices that are expected to be further miniaturized in the future.

It is a typical top view at the time of seeing a line pattern from the upper part. It is typical sectional drawing of a line pattern shape.

<Radiation sensitive composition>
The radiation-sensitive composition contains a [A] polymer, a [B] acid generator, and a [C] compound. The radiation-sensitive composition may contain [D] acid diffusion controller and [E] solvent as suitable components, and contains other optional components as long as the effects of the present invention are not impaired. Also good. Hereinafter, each component will be described.

<[A] polymer>
[A] The polymer is a polymer having the structural unit (I). “Polymer” refers to a compound formed by combining monomers by the formation of a covalent bond, and includes polymers and oligomers. [A] The lower limit of the molecular weight of the polymer is, for example, 500, preferably 1,000. [A] When the polymer has the structural unit (I), the acid dissociable group is dissociated by the action of an acid generated from the acid generator [B] described later. As a result, the solubility of the [A] polymer in the developer changes, so that a pattern can be formed with the radiation-sensitive composition.

[A] The polymer is not particularly limited as long as it has the structural unit (I). For example, the polymer having the structural unit (I) (hereinafter also referred to as “[A1] polymer”), the structural unit (I) And calixarene (hereinafter also referred to as “[A2] polymer”). The “calixarene” refers to a cyclic oligomer in which a plurality of aromatic rings to which a hydroxy group is bonded or heteroaromatic rings to which a hydroxy group is bonded are bonded cyclically through a hydrocarbon group.

[[A1] polymer]
[A1] The polymer is a polymer having the structural unit (I). [A1] In addition to the structural unit (I), the polymer includes a second structural unit represented by the formula (3) (hereinafter also referred to as “structural unit (II)”), a lactone structure, and a cyclic carbonate structure. , May have a structural unit (III) containing a sultone structure or a combination thereof, and may have other structural units other than (I) to (III). [A1] According to the polymer, various structural units can be introduced more easily and the solubility in a developer can be adjusted. According to the radiation sensitive composition, resist performance can be further improved. [A1] The polymer may have one or more of each structural unit. Hereinafter, each structural unit will be described.

[Structural unit (I)]
The structural unit (I) is a structural unit containing an acid dissociable group. [A1] As the structural unit (I) in the polymer, for example, a structural unit represented by the following formula (2-1) (hereinafter also referred to as “structural unit (I-1)”), a structural formula (2-2) ) (Hereinafter also referred to as “structural unit (I-2)”) and the like.

In the above formula (2-1), R ² is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ³ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ⁴ and R ⁵ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a ring member having 3 to 5 members composed of these groups together with the carbon atom to which they are bonded. 20 alicyclic structures are represented.
In the above formula (2-2), R ⁶ is a hydrogen atom or a methyl group. L ¹ is a single bond, —COO— or —CONH—. R ⁷ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ⁸ and R ⁹ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent oxyhydrocarbon group having 1 to 20 carbon atoms.

As the structural unit (I-1), structural units represented by the following formulas (2-1-1) to (2-1-4) (hereinafter referred to as “structural units (I-1-1) to (I-1) -4) ") is preferred. As the structural unit (I-2), a structural unit represented by the following formula (2-2-1) (hereinafter also referred to as “structural unit (I-2-1)”) is preferable.

In the above formulas (2-1-1) to (2-1-4), R ² to R ⁵ have the same meanings as the above formula (2-1). n _p is each independently an integer of 1 to 4.
In the above formula (2-2-1), R ⁶ to R ⁹ are synonymous with the above formula (2-2).

Examples of the structural unit (I-1) include a structural unit represented by the following formula.

In the above formula, R ² has the same meaning as in the above formula (2-1).

Examples of the structural unit (I-2) include a structural unit represented by the following formula.

In the above formula, R ⁶ has the same meaning as in the above formula (2-2).

As the structural unit (I-1), the structural unit (I-1-2) and the structural unit (I-1-3) are preferable, and the structural unit derived from 1-alkylcyclopentan-1-yl (meth) acrylate And structural units derived from 2-adamantyl-2-propyl (meth) acrylate are more preferred.
The structural unit (II-2) is preferably a structural unit (II-2-1), more preferably a structural unit derived from 1-oxyhydrocarbon-substituted-1-alkyloxystyrene, and 1-cycloalkyl-1- A structural unit derived from alkyloxystyrene is more preferable, and a structural unit derived from 1-cyclohexylethyloxy-1-ethyloxystyrene is particularly preferable.

As a minimum of the content rate of structural unit (I), 10 mol% is preferable with respect to all the structural units which comprise a [A1] polymer, 20 mol% is more preferable, 30 mol% is further more preferable, 40 mol% % Is particularly preferred. As an upper limit of the said content rate, 80 mol% is preferable, 70 mol% is more preferable, 60 mol% is further more preferable, 55 mol% is especially preferable. By making the said content rate into the said range, the nano edge roughness performance of the said radiation sensitive composition can be improved more.

[Structural unit (II)]
The structural unit (II) is a structural unit containing a phenolic hydroxyl group. [A1] Since the polymer further has the structural unit (II), the solubility in the developer can be adjusted more appropriately, and as a result, the nanoedge roughness performance of the radiation-sensitive composition is further improved. be able to. In addition, the adhesion of the pattern to the substrate can be improved. Furthermore, in the case of KrF exposure, EUV exposure or electron beam exposure, the sensitivity of the radiation sensitive composition can be further increased.

Examples of the structural unit (II) include a structural unit represented by the following formula (3) (hereinafter also referred to as “structural unit (II-1)”).

In the formula ^{(3), R 15} is a hydrogen atom or a methyl group. L ² is a single bond or a divalent organic group having 1 to 20 carbon atoms. R ¹⁶ is a monovalent organic group having 1 to 20 carbon atoms. p is an integer of 0-2. q is an integer of 0 to 9. When q is 2 or more, the plurality of R ¹⁶ may be the same or different. r is an integer of 1 to 3.

Examples of the structural unit (II) include structural units represented by the following formulas (3-1) to (3-7) (hereinafter also referred to as “structural units (II-1) to (II-7)”), etc. Is mentioned.

In the above formulas (3-1) to (3-7), R ¹⁵ has the same meaning as in the above formula (3).

Of these, the structural unit (II-1) is preferred.

[A1] When the polymer has the structural unit (II), the content ratio of the structural unit (II) is preferably 10 mol%, preferably 30 mol% with respect to all the structural units constituting the [A1] polymer. Is more preferable, and 45 mol% is more preferable. As an upper limit of the said content rate, 80 mol% is preferable, 70 mol% is more preferable, and 60 mol% is further more preferable. By making the content rate of structural unit (II) into the said range, the nano edge roughness performance of the said radiation sensitive composition can further be improved. In addition, the sensitivity in the case of KrF exposure, EUV exposure, or electron beam exposure can be further increased.

[Structural unit (III)]
The structural unit (III) is a structural unit including a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof. [A1] The polymer further includes the structural unit (III), so that the solubility in the developer can be further adjusted, and as a result, the nano-edge roughness performance of the radiation-sensitive composition is further improved. be able to. Further, the adhesion between the pattern and the substrate can be further improved.

Examples of the structural unit (III) include a structural unit represented by the following formula.

In the above formula, R ^L1 represents a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

Among these, the structural unit (III) is preferably a structural unit containing a lactone structure, more preferably a structural unit containing a norbornane lactone structure or a structural unit derived from cyanonorbornane lactone-yl (meth) acrylate.

[A1] When the polymer has the structural unit (III), the lower limit of the content ratio of the structural unit (III) is preferably 10 mol% with respect to all the structural units constituting the polymer. Mole% is more preferable, and 40 mol% is more preferable. As an upper limit of the said content rate, 70 mol% is preferable, 60 mol% is more preferable, and 55 mol% is further more preferable. By making the said content rate into the said range, the nano edge roughness performance of the said radiation sensitive composition can further be improved. Further, the adhesion of the pattern to the substrate can be further improved.

[Other structural units]
[A] The polymer may have other structural units in addition to the structural units (I) to (III). Examples of other structural units include a structural unit containing a polar group and a structural unit containing a non-dissociable hydrocarbon group. Examples of the polar group include an alcoholic hydroxyl group, a carboxy group, a cyano group, a nitro group, and a sulfonamide group. Examples of the non-dissociable hydrocarbon group include a linear alkyl group. As an upper limit of the content rate of another structural unit, 20 mol% is preferable and 10 mol% is more preferable.

[A1] The lower limit of polystyrene-equivalent weight average molecular weight (Mw) by gel permeation chromatography (GPC) of the polymer is preferably 1,500, more preferably 2,000, still more preferably 4,000, 000 is particularly preferred. The upper limit of Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 10,000. [A] By making Mw of a polymer into the said range, the sensitivity and limit resolution of the said radiation sensitive composition can be improved more.

[A1] The upper limit of the ratio (Mw / Mn) of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the polymer is preferably 5, more preferably 3, and even more preferably 2. The lower limit of the ratio is usually 1, and 1.1 is preferable.

Mw and Mn of the polymer in this specification are values measured using gel permeation chromatography (GPC) under the following conditions.
GPC column: 2 "G2000HXL" from Tosoh Corporation, 1 "G3000HXL", 1 "G4000HXL" Column temperature: 40 ° C
Elution solvent: Tetrahydrofuran (Wako Pure Chemical Industries)
Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass
Sample injection volume: 100 μL
Detector: Differential refractometer Standard material: Monodisperse polystyrene

[[A2] polymer]
[A2] The polymer is a calixarene having the structural unit (I). The said radiation sensitive composition can improve nano edge roughness performance more by containing a [A2] polymer. [A2] Examples of the structural unit (I) in the polymer include a structural unit represented by the following formula (2-3) (hereinafter also referred to as “structural unit (I-3)”). [A2] The polymer has a structure in which the structural unit (I) is linked by a chain hydrocarbon group.

In the above formula (2-3), R ¹⁰ is a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent oxyhydrocarbon group having 1 to 20 carbon atoms. R ¹¹ is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms. R ¹² is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ¹³ and R ¹⁴ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a ring member having 3 to 3 members together with the carbon atoms to which these groups are combined with each other. 20 alicyclic structures are represented. a is an integer of 0-6. b is an integer of 0-6. However, a + b is 5 or less. k is 0 or 1. When a is 2 or more, the plurality of R ¹⁰ may be the same or different.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms and the monovalent oxyhydrocarbon group having 1 to 20 carbon atoms represented by R ¹⁰ include R ^{1 in} the formula (1) of the [C] compound described later. And a group similar to the monovalent hydrocarbon group exemplified as the above, a group containing an oxygen atom at the end of the bond side of this group, and the like.

R ¹⁰ is preferably an oxyhydrocarbon group, more preferably an alkoxy group, and still more preferably a methoxy group.

Examples of the divalent hydrocarbon group having 1 to 10 carbon atoms represented by R ¹¹ include one hydrogen atom from the groups exemplified as the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^10. Among the groups excluding, those having 1 to 10 carbon atoms are exemplified.

R ¹¹ is preferably a single bond or an alkanediyl group, more preferably a methanediyl group.

Examples of each group represented by R ¹² , R ¹³ and R ¹⁴ include the same groups as those exemplified as R ³ , R ⁴ and R ^{5 in} the above formula (2-1).

A is preferably an integer of 0 to 2, and more preferably 1. b is preferably an integer of 0 to 2, and more preferably 1.

[A2] The polymer may have other structural units in addition to the structural unit (I). Examples of other structural units include structural units containing a phenolic hydroxyl group.

[A2] The lower limit of the molecular weight of the polymer is preferably 500, more preferably 1,000, and even more preferably 1,500. The upper limit of the molecular weight is preferably 3,000, more preferably 2,000, and even more preferably 1,500. [A2] By setting the molecular weight of the polymer within the above range, the sensitivity and nanoedge roughness performance of the radiation-sensitive composition can be further improved.

[A] The lower limit of the content of the polymer is preferably 70% by mass, more preferably 80% by mass, and still more preferably 85% by mass with respect to the total solid content of the radiation-sensitive composition.

<[A] Polymer Synthesis Method>
[A1] The polymer can be synthesized, for example, by polymerizing a monomer giving each structural unit in a suitable solvent using a radical polymerization initiator or the like.

Examples of radical polymerization initiators include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2-cyclopropylpropio). Nitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), azo radical initiators such as dimethyl 2,2′-azobisisobutyrate; benzoyl peroxide, t-butyl hydroperoxide, cumene And peroxide radical initiators such as hydroperoxide. Of these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferred, and AIBN is more preferred. These radical initiators can be used alone or in combination of two or more.

Examples of the solvent used for the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane;
Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate;
Ketones such as acetone, methyl ethyl ketone, 4-methyl-2-pentanone, 2-heptanone;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Examples thereof include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 4-methyl-2-pentanol. The solvent used for these polymerizations may be used alone or in combination of two or more.

The lower limit of the reaction temperature in the polymerization is preferably 40 ° C, more preferably 50 ° C. As an upper limit of the said reaction temperature, 150 degreeC is preferable and 120 degreeC is more preferable. As a minimum of reaction time in a polymer, 1 hour is preferred and 2 hours is more preferred. The upper limit of the reaction time is preferably 48 hours, more preferably 24 hours.

[A2] The polymer is, for example, a compound having a phenolic hydroxyl group represented by the following formula (a) and an aldehyde represented by the following formula (b) in the presence of an acid such as trifluoroacetic acid, chloroform or the like. A compound which gives an acid-dissociable group such as 2-bromoacetyloxy-2-methyladamantane in a solvent such as N-methylpyrrolidone in the presence of a base such as potassium carbonate. It can synthesize | combine by making it react.

In the above formula (a), R ^{10 ′} is a hydrocarbon group having 1 to 20 carbon atoms. a ′ is an integer of 0 to 7. b ′ is an integer of 1 to 7. However, a ′ + b ′ is 8 or less. k is 0 or 1. When a ′ is 2 or more, a plurality of R ^{10 ′} may be the same or different.
In the above formula (b), Y represents a substituted or unsubstituted j-valent hydrocarbon group having 1 to 30 carbon atoms or a hydrogen atom. j is 1 or 2.

J is preferably 2. Y is preferably an unsubstituted divalent hydrocarbon group, more preferably an alkanediyl group, and still more preferably a propanediyl group.

<[B] Acid generator>
[B] The acid generator is a substance that generates an acid upon exposure. The generated acid dissociates the acid dissociable group or the like of the structural unit (I) of the polymer [A] to produce a carboxy group, a phenolic hydroxyl group, and the like, and the solubility of the polymer [A] in the developer is increased. Since it changes, the inclusion form of the [B] acid generator in the radiation-sensitive composition that can form a pattern from the radiation-sensitive composition is a low-molecular-weight compound form (hereinafter described). It may also be referred to as “[B] acid generator” as appropriate), a form incorporated as part of the polymer, or both forms.

[B] Examples of the acid generator include onium salt compounds, N-sulfonyloxyimide compounds, halogen-containing compounds, diazoketone compounds, and the like.

Examples of the onium salt compounds include sulfonium salts, tetrahydrothiophenium salts, iodonium salts, phosphonium salts, diazonium salts, pyridinium salts, and the like.

Specific examples of the [B] acid generator include compounds described in paragraphs [0080] to [0113] of JP2009-134088A.

Examples of the sulfonium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, triphenylsulfonium 2-bicyclo [2.2.1] hept- 2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1-difluoroethanesulfonate, triphenylsulfonium camphorsulfonate, 4 -Cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-cyclohexyl Ruphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-cyclohexylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexyl Phenyldiphenylsulfonium camphorsulfonate, 4-methanesulfonylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium nonafluoro-n-butanesulfonate, 4-methanesulfonylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-methane Sulfonylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetraph Oro ethanesulfonate, 4-methanesulfonyl-phenyl camphorsulfonate, triphenylsulfonium 1,1,2,2-tetrafluoro-6- (1-adamantanecarbonyloxy) - hexane-1-sulfonate, and the like.

Examples of the tetrahydrothiophenium salt include 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium nona. Fluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiofe Nitro 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium camphorsulfonate , 1- (6-n-Butoxynaphthalen-2-yl Tetrahydrothiophenium trifluoromethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothio Phenium perfluoro-n-octanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2, 2-tetrafluoroethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothiophenium camphorsulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (3,5-dimethyl- -Hydroxyphenyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (3,5-dimethyl -4-hydroxyphenyl) tetrahydrothiophenium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (3,5-dimethyl-4- Hydroxyphenyl) tetrahydrothiophenium camphorsulfonate and the like.

Examples of the iodonium salt include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, diphenyliodonium 2-bicyclo [2.2.1] hept-2-yl- 1,1,2,2-tetrafluoroethanesulfonate, diphenyliodonium camphorsulfonate, bis (4-tert-butylphenyl) iodonium trifluoromethanesulfonate, bis (4-tert-butylphenyl) iodonium nonafluoro-n-butanesulfonate, Bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, bis (4-t-butylphenyl) iodonium 2-bicyclo [2. .1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, bis (4-t- butylphenyl) iodonium camphorsulfonate, and the like.

Examples of N-sulfonyloxyimide compounds include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (nonafluoro-n-butanesulfonyloxy). ) Bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (perfluoro-n-octanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2 , 3-dicarboximide, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonyloxy) bicyclo [2.2.1] hept- 5-ene-2,3-dicarboximide, N- (2- (3- tetracyclo ^[4.4.0.1 2,5 ^{.1 7,10]} dodecanyl) -1,1-difluoro-ethanone Sulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dicarboximide, N- (camphorsulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3 -Dicarboximide etc. can be mentioned.

[B] As the acid generator, a compound represented by the following formula (4) can be used. [B] Since the acid generator has the following structure, the diffusion length of the acid generated by exposure in the resist film is appropriately shortened due to the interaction with the polar structure of the [A] polymer and the like. As a result, the resist performance of the radiation-sensitive composition can be further improved.

In the above formula (4), R ¹⁷ is a monovalent group containing an alicyclic structure having 6 or more ring members or a monovalent group containing an aliphatic heterocyclic structure having 6 or more ring members. R ¹⁸ is a fluorinated alkanediyl group having 1 to 10 carbon atoms. G ⁺ is a monovalent radiation-sensitive onium cation.

Examples of the monovalent group including an alicyclic structure having 6 or more ring members represented by R ¹⁷ include monocyclic cycloalkyl groups such as a cyclooctyl group, a cyclononyl group, a cyclodecyl group, and a cyclododecyl group;
A monocyclic cycloalkenyl group such as a cyclooctenyl group and a cyclodecenyl group;
A polycyclic cycloalkyl group such as a norbornyl group, an adamantyl group, a tricyclodecyl group, a tetracyclododecyl group;
And polycyclic cycloalkenyl groups such as a norbornenyl group and a tricyclodecenyl group.

Examples of the monovalent group containing an aliphatic heterocyclic structure having 6 or more ring members represented by R ¹⁷ include a group containing a lactone structure such as a norbornanelactone-yl group;
A group containing a sultone structure such as a norbornane sultone-yl group;
An oxygen atom-containing heterocyclic group such as an oxacycloheptyl group and an oxanorbornyl group;
A nitrogen atom-containing heterocyclic group such as an azacyclohexyl group, an azacycloheptyl group, a diazabicyclooctane-yl group;
And sulfur atom-containing heterocyclic groups such as a thiacycloheptyl group and a thianorbornyl group.

The lower limit of the number of ring members of the group represented by R ¹⁷ is preferably 7, more preferably 8, and still more preferably 9. The upper limit of the number of ring members is preferably 15, more preferably 13, and still more preferably 11. By setting the number of ring members of the group represented by R ¹⁷ within the above range, it is considered that the diffusion length of the acid is further appropriately shortened, and as a result, the resist performance of the radiation-sensitive composition is further improved. be able to.

Among these, R ¹⁷ is preferably a monovalent group containing an alicyclic structure having 9 or more ring members and a monovalent group containing an aliphatic heterocyclic structure having 9 or more ring members, an adamantyl group, a hydroxyadamantyl group A norbornanelactone-yl group and a 5-oxo-4-oxatricyclo [4.3.1.1 ^3,8 ] undecan-yl group are more preferred, and an adamantyl group is more preferred.

Examples of the fluorinated alkanediyl group having 1 to 10 carbon atoms represented by R ¹⁸ include one or more hydrogen atoms of an alkanediyl group having 1 to 10 carbon atoms such as a methanediyl group, an ethanediyl group, and a propanediyl group. And a group in which is substituted with a fluorine atom. Among these, SO ₃ ^- fluorinated alkane diyl group which has a fluorine atom to carbon atom is bonded to adjacent groups are preferred, SO ₃ ^- 2 fluorine atoms to the carbon atom adjacent to the group is attached More preferred are fluorinated alkanediyl groups, 1,1-difluoromethanediyl group, 1,1-difluoroethanediyl group, 1,1,3,3,3-pentafluoro-1,2-propanediyl group, 1,1 1,2,2-tetrafluoroethanediyl group, 1,1,2,2-tetrafluorobutanediyl group and 1,1,2,2-tetrafluorohexanediyl group are more preferable.

The monovalent radiation-sensitive onium cation represented by G ⁺ is a cation that decomposes upon exposure to exposure light. In the exposed portion, sulfonic acid is generated from protons generated by the decomposition of the radiation-sensitive onium cation and sulfonate anions. Examples of the monovalent radiation-sensitive onium cation represented by X ⁺ include elements such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, and Bi. Examples include radiation-sensitive onium cations. Examples of the cation containing S (sulfur) as an element include a sulfonium cation and a tetrahydrothiophenium cation. Examples of the cation containing I (iodine) as an element include an iodonium cation. Among these, a sulfonium cation represented by the following formula (G-1), a tetrahydrothiophenium cation represented by the following formula (G-2), and an iodonium cation represented by the following formula (G-3) preferable.

In the above formula (G-1), R ^a1 , R ^a2 and R ^a3 each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted group. aromatic hydrocarbon group having 6 to 12 carbon atoms, represents or is a -OSO ₂ -R ^P or _-SO 2 -R ^Q, or two or more are combined with each other configured ring of these groups . R ^P and R ^Q are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k1, k2 and k3 are each independently an integer of 0 to 5. When R ^a1 ~ ^{R a3} and ^{R P} and ^{R Q} are a plurality each of the plurality of ^R a1 ^{~ R a3} and ^{R P} and ^{R Q} may be the same as or different from each other.

In the above formula (G-2), R ^b1 represents a substituted or unsubstituted linear or branched alkyl group having 1 to 8 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon having 6 to 8 carbon atoms. It is a group. k4 is an integer of 0 to 7. If R ^b1 is plural, the plurality of R ^b1 may be the same or different, and plural R ^b1 may represent a constructed ring aligned with each other. R ^b2 is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. k5 is an integer of 0 to 6. If R ^b2 is plural, the plurality of R ^b2 may be the same or different, and plural R ^b2 may represent a keyed configured ring structure. t is an integer of 0 to 3.

In the above formula (G-3), R ^c1 and R ^c2 each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon number of 6 aromatic hydrocarbon group having 1-12, indicating whether it is -OSO ₂ -R ^R or _-SO 2 -R ^S, or two or more are combined with each other configured ring of these groups. R ^R and R ^S each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms. Or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k6 and k7 are each independently an integer of 0 to 5. R ^{c1, R} c2, ^R when ^R and ^{R S} is plural respective plurality of ^{R c1,} R c2, ^{R R} and ^{R S} may have respectively the same or different.

Examples of the unsubstituted linear alkyl group represented by R ^a1 to R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 include a methyl group, an ethyl group, an n-propyl group, and an n-butyl group. Etc.
Examples of the unsubstituted branched alkyl group represented by R ^a1 to R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 include i-propyl group, i-butyl group, sec-butyl group, t -A butyl group etc. are mentioned.
Examples of the unsubstituted aromatic hydrocarbon group represented by R ^a1 to R ^a3 , R ^c1 and R ^c2 include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a mesityl group, and a naphthyl group; a benzyl group, Examples include aralkyl groups such as phenethyl group.
Examples of the unsubstituted aromatic hydrocarbon group represented by R ^b1 and R ^b2 include a phenyl group, a tolyl group, and a benzyl group.

Examples of the substituent that may be substituted for the hydrogen atom of the alkyl group and aromatic hydrocarbon group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, a hydroxy group, a carboxy group, and a cyano group. Nitro group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, acyloxy group and the like. Among these, a halogen atom is preferable and a fluorine atom is more preferable.

R ^a1 to R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 include an unsubstituted linear or branched alkyl group, a fluorinated alkyl group, and an unsubstituted monovalent aromatic hydrocarbon group. , —OSO ₂ —R ″ and —SO ₂ —R ″ are preferred, fluorinated alkyl groups and unsubstituted monovalent aromatic hydrocarbon groups are more preferred, and fluorinated alkyl groups are more preferred. R ″ is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

In the above formula (G-1), k1, k2 and k3 are preferably integers of 0 to 2, more preferably 0 and 1, and even more preferably 0.
In the above formula (G-2), k4 is preferably an integer of 0 to 2, more preferably 0 and 1, and further preferably 1. k5 is preferably an integer of 0 to 2, more preferably 0 and 1, and still more preferably 0.
In the above formula (G-3), k6 and k7 are preferably integers of 0 to 2, more preferably 0 and 1, and still more preferably 0.

Examples of the acid generator represented by the above formula (4) include compounds represented by the following formulas (4-1) to (4-14) (hereinafter referred to as “compounds (4-1) to (4-14)”. Also).

In the above formulas (4-1) to (4-14), G ⁺ has the same meaning as in the above formula (4).

[B] The acid generator is preferably an onium salt compound, more preferably a sulfonium salt, still more preferably a triphenylsulfonium salt, and particularly preferably triphenylsulfonium nonafluoro-n-butanesulfonate and the compound (4-14).

[B] The acid generator is also preferably a polymer in which the structure of an acid generator such as a polymer having a structural unit represented by the following formula (5) is incorporated as a part of the polymer.

In the above formula ^{(5), R 19} is a hydrogen atom or a methyl group. L ³ is a single bond, —COO—, —Ar—, —COO—Ar— or —Ar—OSO ₂ —. Ar is a substituted or unsubstituted arenediyl group having 6 to 20 carbon atoms. R ²⁰ is a fluorinated alkanediyl group having 1 to 10 carbon atoms. G ⁺ is a monovalent radiation-sensitive onium cation.

[B] When the acid generator is a [B] acid generator, the lower limit of the content of the [B] acid generator is preferably 0.1 parts by mass with respect to 100 parts by mass of the [A] polymer. 1 mass part is more preferable, 5 mass parts is further more preferable, 10 mass parts is especially preferable, and 20 mass parts is further especially preferable. As an upper limit of the said content, 50 mass parts is preferable, 40 mass parts or less are more preferable, 35 mass parts or less are more preferable, 32 mass parts is especially preferable. [B] By making content of an acid generator into the said range, the sensitivity of the said radiation sensitive composition can further be improved. [B] 1 type (s) or 2 or more types can be used for an acid generator.

<[C] Compound>
[C] The compound is a compound represented by the following formula (1). The radiation-sensitive composition contains a [C] compound in addition to the [A] polymer and the [B] acid generator, so that sensitivity, nanoedge roughness performance, storage stability, and limit resolution are achieved. Rise. The reason why the radiation-sensitive composition has the above-described configuration provides the above-mentioned effect is not necessarily clear, but can be inferred as follows, for example. That is, by the action of the mononuclear metal complex of the [C] compound, secondary electrons are generated from the exposure light, and an acid is generated from the secondary electrons and the [B] acid generator. As a result, the sensitivity of the radiation sensitive composition can be improved. In addition, since the [C] compound is a mononuclear metal complex having an oxyhydrocarbon group as a ligand, it can be considered to exist relatively stably, and the storage stability of the radiation-sensitive composition is excellent. Can be maintained. In addition, since metal aggregation hardly occurs, the nano edge roughness of the pattern can be reduced. Furthermore, it is considered that when the [C] compound has an alkoxy ligand, the adhesion of the pattern to the substrate can be increased, the falling limit lower limit dimension can be reduced, and as a result, the limit resolution can be improved.

In said formula (1), M is a metal atom. L is a ligand other than OR ¹ . R ¹ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. x is an integer of 0 to 5. y is an integer of 1 to 6. However, x + y is 6 or less. When x is 2 or more, the plurality of L may be the same or different. When y is 2 or more, the plurality of R ¹ may be the same or different.

As the metal atom of M, for example, Group 3, Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, Group 10, Group 11, Group 12, Group 13 Group, Group 14 metal atoms and the like. Among these, metal atoms of Group 4, Group 5, Group 6 and Group 14 are preferred from the viewpoint of further promoting the generation of secondary electrons, and the sensitivity can be further improved. More preferred are Group 5, Group 6 and Group 14 metal atoms.

As the metal atom, it is considered that the generation of secondary electrons is further promoted, and titanium, zirconium, hafnium, tantalum, tungsten and tin are preferable, and hafnium, tantalum and tin are more preferable from the viewpoint of further improving the sensitivity. .

Examples of the ligand represented by L include a monodentate ligand and a polydentate ligand.

Examples of the monodentate ligand include hydroxo ligand (OH), carboxy ligand (COOH), amide ligand, acyloxy ligand, amine ligand and the like.

Examples of the amide ligand include an unsubstituted amide ligand (NH ₂ ), a methylamide ligand (NHMe), a dimethylamide ligand (NMe ₂ ), a diethylamide ligand (NEt ₂ ), and a dipropylamide ligand. Examples include a ligand (NPr ₂ ).

Examples of the acyloxy ligand include formyloxy ligand, acetyloxy ligand, propionyloxy ligand, stearoyloxy ligand, acryloxy ligand and the like.

Examples of the amine ligand include a pyridine ligand, a trimethylamine ligand, and a piperidine ligand.

Examples of the polydentate ligand include hydroxy acid ester, β-diketone, β-keto ester, β-dicarboxylic acid ester, o-acylphenol, hydrocarbon having π bond, diphosphine, ammonia and the like.

Examples of the hydroxy acid ester include glycolic acid ester, lactic acid ester, 2-hydroxycyclohexane-1-carboxylic acid ester, and salicylic acid ester.

Examples of β-diketone include acetylacetone, 3-methyl-2,4-pentanedione, 3-ethyl-2,4-pentanedione, 2,2-dimethyl-3,5-hexanedione, and the like.

Examples of β-ketoesters include acetoacetate ester, α-alkyl-substituted acetoacetate ester, β-ketopentanoic acid ester, benzoyl acetate ester, 1,3-acetone dicarboxylic acid ester and the like.

Examples of β-dicarboxylic acid esters include malonic acid diesters, α-alkyl substituted malonic acid diesters, α-cycloalkyl substituted malonic acid diesters, α-aryl substituted malonic acid diesters, and the like.

Examples of o-acylphenol include o-hydroxyacetophenone and o-hydroxybenzophenone.

Examples of hydrocarbons having a π bond include chain olefins such as ethylene and propylene;
Cyclic olefins such as cyclopentene, cyclohexene, norbornene;
Chain dienes such as butadiene and isoprene;
Cyclic dienes such as cyclopentadiene, methylcyclopentadiene, pentamethylcyclopentadiene, cyclohexadiene, norbornadiene;
Examples thereof include aromatic hydrocarbons such as benzene, toluene, xylene, hexamethylbenzene, naphthalene, and indene.

Examples of the diphosphine include 1,1-bis (diphenylphosphino) methane, 1,2-bis (diphenylphosphino) ethane, 1,3-bis (diphenylphosphino) propane, 2,2′-bis (diphenylphosphine). Phino) -1,1′-binaphthyl, 1,1′-bis (diphenylphosphino) ferrocene and the like.

As the ligand represented by L, an acyloxy ligand, an amine ligand, a β-diketone, an o-acylphenol, and a hydrocarbon having a π bond are preferable. An acetyloxy ligand, a stearoyloxy ligand More preferred are pyridine, acetylacetone, 3,3-dimethyl-3,5-hexanedione, o-hydroxyacetophenone and cyclopentadiene.

[C] The monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ¹ of the OR ¹ ligand of the compound is, for example, a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, carbon number And a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t -An alkyl group such as a butyl group;
Alkenyl groups such as ethenyl group, propenyl group, butenyl group, pentenyl group;
Examples thereof include alkynyl groups such as ethynyl group, propynyl group, butynyl group, and pentynyl group.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include cycloalkyl groups such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group;
And cycloalkenyl groups such as cyclopropenyl group, cyclobutenyl group, cyclopentenyl group, cyclohexenyl group and norbornenyl group.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include aryl groups such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and an anthryl group;
Examples thereof include aralkyl groups such as benzyl group, phenethyl group, and naphthylmethyl group.

R ¹ is preferably a chain hydrocarbon group or an aromatic hydrocarbon group, more preferably an alkyl group or an aryl group, from the viewpoint of further improving the sensitivity of the radiation-sensitive composition, i-propyl group, n- A butyl group, a t-butyl group, a phenyl group, and a 3,5-dimethylphenyl group are more preferable, and an i-propyl group, a t-butyl group, and a phenyl group are particularly preferable.

X is preferably an integer of 1 to 5, more preferably an integer of 1 to 3, more preferably 1 and 2, and particularly preferably 1. By setting x in the above range, the storage stability of the radiation-sensitive composition can be further improved. y is preferably an integer of 1 to 4, more preferably an integer of 2 to 4. The sensitivity of the said radiation sensitive composition can be improved more by making y into the said range.

Examples of the [C] compound include titanium / tetra n-propoxide, titanium / tetra n-butoxide, titanium / tetra i-propoxide, titanium / aminopropyl / trimethoxide, titanium / tri n-butoxide / stear as titanium compounds. Rate, titanium, triethoxide, mono (acetylacetonate), titanium, tri-n-propoxide, mono (acetylacetonate), titanium, tri-i-propoxide, mono (acetylacetonate), titanium, diisopropoxide, Bis (acetylacetonate), titanium / di-n-butoxide / bis (acetylacetonate), etc.
As zirconium compounds, zirconium tetra-propoxide, zirconium tetra n-butoxide, zirconium 2- (3,4-epoxycyclohexyl) ethyl trimethoxide, zirconium γ-glycidoxypropyl trimethoxide, zirconium 3- Isocyanopropyl trimethoxide, zirconium 3-methacryloxypropyl trimethoxide, zirconium aminopropyl triethoxide, zirconium 3-isocyanopropyl triethoxide, zirconium triethoxide mono (acetylacetonate), zirconium tri-propoxy Mono (acetylacetonate), zirconium tri-i-propoxide mono (acetylacetonate), zirconium tributoxide Mono (acetylacetonate), zirconium di n- butoxide bis (acetylacetonate), zirconium tri (3-acryloxypropyl) Monometokishido the like,
Hafnium compounds include hafnium tetraethoxide, hafnium tetraisopropoxide, hafnium di-t-butoxide bis (2,2-dimethyl-3,5-hexanedionate), etc.
Examples of tantalum compounds include tantalum pentaethoxide, tantalum tetraphenoxide (2-acetylphenolate), etc.
Tungsten compounds such as tungsten pentamethoxide, tungsten hexahexoxide, tungsten pentacyclodienyl tetra (3,5-dimethylphenoxide),
Examples of the tin compound include tin / tetramethoxide, tin / tetra-t-butoxide, tin / pyridine / tri-t-butoxide / monoacetate, and the like.

[C] Among these compounds, titanium, tri-n-butoxide, stearate, titanium, diisopropoxide, bis (acetylacetonate), titanium, tetra-i-propoxide, zirconium, tributoxide, mono (Acetylacetonate), hafnium di-t-butoxide bis (2,2-dimethyl-3,5-hexanedionate), hafnium tetraisopropoxide, tantalum tetraphenoxide (2-acetylphenolate), Tungsten pentacyclodienyl tetra (3,5-dimethylphenoxide) and tin pyridine tri t-butoxide acetate are preferred.

[A] The lower limit of the content of the [C] compound with respect to 100 parts by mass of the polymer is preferably 0.1 parts by mass, more preferably 0.5 parts by mass, further preferably 1 part by mass, particularly 2 parts by mass. Preferably, 4 parts by weight is more particularly preferred. As an upper limit of the said content, 50 mass parts is preferable, 40 mass parts is more preferable, 30 mass parts is further more preferable, 20 mass parts is especially preferable, 15 mass parts is further especially preferable.

[B] When the acid generator is a [B] acid generator, the lower limit of the content of the [C] compound with respect to 100 parts by mass of the [B] acid generator is preferably 1 part by mass and more preferably 4 parts by mass. Preferably, 7 parts by mass is more preferable, and 9 parts by mass is particularly preferable. As an upper limit of the said content, 100 mass parts is preferable, 70 mass parts is more preferable, 50 mass parts is further more preferable, 30 mass parts is especially preferable.

By setting the content of the [C] compound in the above range, the radiation-sensitive composition can further improve sensitivity, nanoedge roughness performance, and limit resolution. The radiation-sensitive composition may contain only one type of [C] compound or two or more types.

<[D] Acid diffusion controller>
The said radiation sensitive composition may contain a [D] acid diffusion control body as needed. [D] The acid diffusion controller controls the diffusion phenomenon in the resist film of the acid generated from the [B] acid generator by exposure, and has an effect of suppressing an undesirable chemical reaction in the non-exposed region. In addition, the storage stability of the radiation-sensitive composition is further improved, and the resolution as a resist is further improved. Furthermore, a change in the line width of the resist pattern due to fluctuations in the holding time from exposure to development processing can be suppressed, and a radiation-sensitive composition excellent in process stability can be obtained. [D] The content of the acid diffusion controller in the radiation-sensitive composition is incorporated as a part of the polymer even in the form of a free compound (hereinafter referred to as “[D] acid diffusion controller” as appropriate). Either of these forms may be used.

[D] Examples of the acid diffusion controller include a compound represented by the following formula (6a) (hereinafter also referred to as “nitrogen-containing compound (I)”), a compound having two nitrogen atoms in the same molecule (hereinafter referred to as “nitrogen-containing compound (I)”). "Nitrogen-containing compound (II)"), compounds having three nitrogen atoms (hereinafter also referred to as "nitrogen-containing compound (III)"), amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, etc. It is done.

In the above formula (6a), R ²¹ , R ²² and R ²³ are each independently a hydrogen atom, an optionally substituted linear, branched or cyclic alkyl group, aryl group or aralkyl group. .

Examples of the nitrogen-containing compound (I) include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine and tri-n-pentylamine; and aromatics such as aniline Group amines and the like.

Examples of the nitrogen-containing compound (II) include ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, and the like.

Examples of the nitrogen-containing compound (III) include polyamine compounds such as polyethyleneimine and polyallylamine; and polymers such as dimethylaminoethylacrylamide.

Examples of the amide group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, propionamide, benzamide, pyrrolidone, N-methylpyrrolidone and the like. It is done.

Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, 1,3-diphenylurea, tributylthiourea and the like.

Examples of the nitrogen-containing heterocyclic compound include pyridines such as pyridine and 2-methylpyridine; morpholines such as N-propylmorpholine and N- (undecan-1-ylcarbonyloxyethyl) morpholine; pyrazine, pyrazole and the like. .

In addition, as the nitrogen-containing organic compound, a compound having an acid dissociable group can also be used. Examples of the nitrogen-containing organic compound having such an acid dissociable group include Nt-butoxycarbonylpiperidine, Nt-butoxycarbonylimidazole, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonyl-2 -Phenylbenzimidazole, N- (t-butoxycarbonyl) di-n-octylamine, N- (t-butoxycarbonyl) diethanolamine, N- (t-butoxycarbonyl) dicyclohexylamine, N- (t-butoxycarbonyl) diphenylamine Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-amyloxycarbonyl-4-hydroxypiperidine and the like.

Further, as the [D] acid diffusion control agent, a photodegradable base that is exposed to light and generates a weak acid can be used. Examples of the photodegradable base include an onium salt compound that loses acid diffusion controllability by being decomposed by exposure. Examples of the onium salt compound include a sulfonium salt compound represented by the following formula (6b-1), an iodonium salt compound represented by the following formula (6b-2), and the like.

In the above formulas (6b-1) and (6b-2), R ²⁴ to R ²⁸ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a hydroxy group or a halogen atom. E ⁻ and Q ⁻ are each independently an anion represented by OH ⁻ , R ^β —COO ⁻ , R ^β —SO ₃ ^— or the following formula (6b-3). However, R ( ^beta) is an alkyl group, an aryl group, or an aralkyl group.

In the above formula (6b-3), R ²⁹ is a linear or branched alkyl group having 1 to 12 carbon atoms in which part or all of the hydrogen atoms may be substituted with fluorine atoms, or 1 carbon atom 12 to 12 linear or branched alkoxy groups. u is an integer of 0-2. When u is 2, two R ²⁹ may be the same or different.

Of these, the photodegradable base is preferably a sulfonium salt, more preferably a triarylsulfonium salt, and even more preferably triphenylsulfonium salicylate and triphenylsulfonium 10-camphorsulfonate.

When the radiation-sensitive composition contains a [D] acid diffusion controller, when the [D] acid diffusion controller is a [D] acid diffusion controller, the lower limit of the content of the [D] acid diffusion controller As for [A] polymer 100 mass parts, 0.1 mass part is preferred, 0.5 mass part is more preferred, and 1 mass part is still more preferred. As an upper limit of the said content, 20 mass parts is preferable, 15 mass parts is more preferable, 10 mass parts is further more preferable, 7 mass parts is especially preferable. [D] By making content of an acid diffusion control agent into the said range, the resolution of the said radiation sensitive composition, storage stability, etc. can be improved.

<[E] solvent>
The radiation-sensitive composition usually contains a [E] solvent. [E] The solvent is particularly limited as long as it is a solvent capable of dissolving or dispersing at least the [A] polymer, the [B] acid generator, the [C] compound, and the optionally contained [D] acid diffusion controller. Not.

[E] Examples of the solvent include alcohol solvents, ether solvents, ketone solvents, amide solvents, ester solvents, hydrocarbon solvents, and the like.

Examples of the alcohol solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol , Sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec -Monoalcohol solvents such as heptadecyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2 Polyhydric alcohol solvents such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

Examples of ether solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether;
Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran;
Aromatic ring-containing ether solvents such as diphenyl ether and anisole (methylphenyl ether) are exemplified.

Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, 2-heptanone (methyl-n-pentyl ketone), ethyl-n-butyl ketone. Chain ketone solvents such as methyl-n-hexyl ketone, di-iso-butyl ketone and trimethylnonanone:
Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and methylcyclohexanone:
Examples include 2,4-pentanedione, acetonylacetone, acetophenone, and the like.

Examples of the amide solvent include cyclic amide solvents such as N, N′-dimethylimidazolidinone and N-methylpyrrolidone;
Examples thereof include chain amide solvents such as N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, and N-methylpropionamide.

Examples of ester solvents include methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, n-pentyl acetate, i-pentyl acetate, sec Acetate solvents such as pentyl, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methylcyclohexyl acetate, n-nonyl acetate;
Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether Polyhydric alcohol partial ether acetate solvents such as acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate;
Carbonate solvents such as dimethyl carbonate and diethyl carbonate;
Diethyl acetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl acetoacetate, ethyl acetoacetate, methyl lactate, ethyl lactate N-butyl lactate, n-amyl lactate, diethyl malonate, dimethyl phthalate, diethyl phthalate and the like.

Examples of hydrocarbon solvents include n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, cyclohexane , Aliphatic hydrocarbon solvents such as methylcyclohexane;
Fragrances such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propylbenzene, n-amylnaphthalene Group hydrocarbon solvents and the like.

Of these, ester solvents and ketone solvents are preferred, polyhydric alcohol partial ether acetate solvents, lactate esters and cyclic ketone solvents are more preferred, and propylene glycol monomethyl ether acetate, ethyl lactate and cyclohexanone are even more preferred. The radiation-sensitive composition may contain one or more [E] solvents.

<Other optional components>
In addition to the above components [A] to [E], the radiation-sensitive composition may contain, for example, a fluorine atom-containing polymer, a surfactant and the like as other optional components. The radiation-sensitive composition may contain one or more other optional components, respectively.

<Fluorine atom-containing polymer>
The fluorine atom-containing polymer is a polymer having a higher fluorine atom content than the [A] polymer. When the radiation-sensitive composition contains a fluorine atom-containing polymer, when the resist film is formed, the distribution is unevenly distributed near the resist film surface due to the oil-repellent characteristics of the fluorine atom-containing polymer in the resist film. It is possible to prevent the acid generator, the acid diffusion controller and the like from being eluted into the immersion medium during immersion exposure. Further, due to the water-repellent characteristics of this fluorine atom-containing polymer, the advancing contact angle between the resist film and the immersion medium can be controlled within a desired range, and the occurrence of bubble defects can be suppressed. Furthermore, the receding contact angle between the resist film and the immersion medium is increased, and high-speed scanning exposure is possible without leaving water droplets. Thus, the said radiation sensitive composition can form the resist film suitable for an immersion exposure method by further containing a fluorine atom containing polymer.

As a minimum of content of a fluorine atom content polymer, 0.1 mass part is preferred to 100 mass parts of [A] polymer, 0.5 mass part is more preferred, and 1 mass part is still more preferred. As an upper limit of the said content, 20 mass parts is preferable, 15 mass parts is more preferable, and 10 mass parts is further more preferable.

[Surfactant]
Surfactants have the effect of improving coatability, striation, developability, and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol diacrylate. Nonionic surfactants such as stearate; commercially available products include KP341 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, Kyoeisha Chemical Co., Ltd.), F-top EF301, EF303, EF352 (above, Tochem Products), MegaFuck F171, F173 (above, DIC), Florard FC430, FC431 (above, Sumitomo 3M) Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (above, Asahi Glass Industrial Co., Ltd.) Can be mentioned. As an upper limit of content of the said surfactant, 2 mass parts is preferable with respect to 100 mass parts of [A] polymers.

<Method for preparing radiation-sensitive composition>
The radiation-sensitive composition is, for example, a mixture of [A] polymer, [B] acid generator, [C] compound and other optional components and [E] solvent as required, preferably, The obtained mixture can be prepared by filtering with a membrane filter having a pore size of about 0.2 μm. The lower limit of the solid content concentration of the radiation-sensitive composition is preferably 0.1% by mass, more preferably 0.5% by mass, further preferably 1% by mass, and particularly preferably 1.5% by mass. The upper limit of the solid content concentration is preferably 50% by mass, more preferably 30% by mass, further preferably 10% by mass, and particularly preferably 5% by mass.

The radiation-sensitive composition can be used both for forming a positive pattern using an alkaline developer and for forming a negative pattern using a developer containing an organic solvent.

<Pattern formation method>
The pattern forming method includes a step of forming a film (hereinafter also referred to as “film forming step”), a step of exposing the film (hereinafter also referred to as “exposure step”), and a step of developing the exposed film. (Hereinafter also referred to as “development process”). The said pattern formation method forms the said film | membrane with the said radiation sensitive composition. According to the pattern forming method, since the radiation-sensitive composition described above is used, a pattern with high sensitivity and excellent nano edge roughness can be formed. Hereinafter, each step will be described.

[Film formation process]
In this step, a film is formed using the radiation-sensitive composition. The film can be formed, for example, by applying a radiation sensitive composition on a substrate. Although it does not specifically limit as an application | coating method, For example, appropriate application | coating means, such as spin coating, cast coating, roll coating, can be employ | adopted. Examples of the substrate include a silicon wafer and a wafer coated with aluminum. Specifically, after applying the radiation-sensitive composition so that the resulting film has a predetermined thickness, the solvent in the coating film is volatilized by pre-baking (PB) as necessary.

The lower limit of the average film thickness of the film is preferably 1 nm, more preferably 5 nm, still more preferably 10 nm, and particularly preferably 20 nm. The upper limit of the average thickness is preferably 1,000 nm, more preferably 200 nm, further preferably 100 nm, and particularly preferably 50 nm.

The lower limit of the PB temperature is usually 60 ° C., preferably 80 ° C. As an upper limit of the temperature of PB, it is 140 degreeC normally and 120 degreeC is preferable. The lower limit of the PB time is usually 5 seconds, and preferably 10 seconds. The upper limit of the PB time is usually 600 seconds, and preferably 300 seconds.

[Exposure process]
In this step, the film formed in the film forming step is exposed. In some cases, this exposure is performed by irradiating radiation through a mask having a predetermined pattern through an immersion medium such as water. Examples of the radiation include visible rays, ultraviolet rays, far ultraviolet rays, vacuum ultraviolet rays (extreme ultraviolet rays (EUV); wavelength 13.5 nm), electromagnetic waves such as X-rays and γ rays, and charged particle beams such as electron rays and α rays. Can be mentioned. Among these, radiation that emits more secondary electrons from the [B] particles by exposure is preferable, and EUV and electron beams are more preferable.

Further, post-exposure baking (PEB) may be performed after exposure. As a minimum of the temperature of PEB, it is 50 degreeC normally and 80 degreeC is preferable. The upper limit of the PEB temperature is usually 180 ° C, preferably 130 ° C. The lower limit of the PEB time is usually 5 seconds, and preferably 10 seconds. The upper limit of the PEB time is usually 600 seconds, and preferably 300 seconds.

In the present invention, in order to maximize the potential of the radiation-sensitive composition, for example, an organic or inorganic antireflection film can be formed on the substrate to be used. Moreover, in order to prevent the influence of the basic impurity etc. which are contained in environmental atmosphere, a protective film can also be provided, for example on a coating film. When immersion exposure is performed, an immersion protective film may be provided on the film, for example, in order to avoid direct contact between the immersion medium and the film.

[Development process]
In this step, the film exposed in the exposure step is developed. Examples of the developer used for the development include an alkaline aqueous solution and an organic solvent-containing solution.

Examples of the alkaline aqueous solution include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, Ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4. 3.0] -5-nonene, and an alkaline aqueous solution in which at least one alkaline compound is dissolved.

The lower limit of the content of the alkaline compound in the alkaline aqueous solution is preferably 0.1% by mass, more preferably 0.5% by mass, and even more preferably 1% by mass. As an upper limit of the said content, 20 mass% is preferable, 10 mass% is more preferable, and 5 mass% is further more preferable.

As the alkaline aqueous solution, a TMAH aqueous solution is preferable, and a 2.38 mass% TMAH aqueous solution is more preferable.

Examples of the organic solvent in the organic solvent-containing liquid include the same organic solvents exemplified as the [D] solvent of the radiation-sensitive composition. Of these, ester solvents are preferred, and butyl acetate is more preferred.

The lower limit of the content of the organic solvent in the organic solvent developer is preferably 80% by mass, more preferably 90% by mass, further preferably 95% by mass, and particularly preferably 99% by mass.

These developers may be used alone or in combination of two or more. In general, after development, the substrate is washed with water or the like and dried.

When a alkaline aqueous solution is used as the developer, a positive pattern can be obtained. In addition, when an organic solvent is used as the developer, a negative pattern can be obtained.

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. The measuring method of the physical property value in a present Example is shown below.

[Weight average molecular weight (Mw) and number average molecular weight (Mn)]
Mw and Mn of the polymer are GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL, Tosoh Corporation), flow rate 1.0 mL / min, elution solvent tetrahydrofuran, sample concentration 1.0 mass%, sample Measurement was performed by gel permeation chromatography (GPC) using monodisperse polystyrene as a standard, using a differential refractometer as a detector under the analysis conditions of an injection amount of 100 μL and a column temperature of 40 ° C.

[ ¹³ C-NMR analysis]
The ¹³ C-NMR analysis for determining the content of the structural unit of the polymer uses a nuclear magnetic resonance apparatus (“JNM-ECX400” manufactured by JEOL Ltd.), uses CDCl ₃ as a measurement solvent, and uses tetramethylsilane ( TMS) was performed as an internal standard.

<[A] Synthesis of polymer>
[A] Monomers used for polymer synthesis are shown below.

[Synthesis Example 1]
55 g (50 mol%) of the above compound (M-1), 45 g (50 mol%) of the above compound (M-2) and 3 g of AIBN were dissolved in 300 g of methyl ethyl ketone, and the reaction temperature was maintained at 78 ° C. in a nitrogen atmosphere. For 6 hours. After the polymerization, the reaction solution was dropped into 2,000 g of methanol to solidify the polymer. Next, this polymer was washed twice with 300 g of methanol, and the resulting white powder was filtered and dried overnight at 50 ° C. under reduced pressure to obtain a polymer (A-1). The polymer (A-1) had Mw of 7,000 and Mw / Mn of 2.10. As a result of ¹³ C-NMR analysis, the content of each structural unit derived from the compound (M-1) and the compound (M-2) was 52 mol% and 48 mol%, respectively.

[Synthesis Example 2]
After dissolving 55 g (42 mol%) of the above compound (M-3), 45 g (58 mol%) of the above compound (M-1), 3 g of AIBN and 1 g of t-dodecyl mercaptan in 150 g of propylene glycol monomethyl ether, The polymerization was carried out for 16 hours while maintaining the reaction temperature at 70 ° C. After the polymerization, the reaction solution was dropped into 1,000 g of n-hexane to coagulate and purify the polymer. Next, 150 g of propylene glycol monomethyl ether was added to the polymer again, and then 150 g of methanol, 37 g of triethylamine and 7 g of water were further added, and a hydrolysis reaction was performed for 8 hours while refluxing at the boiling point. The structural unit derived from -3) was deacetylated. After the reaction, the solvent and triethylamine were distilled off under reduced pressure, and the obtained polymer was dissolved in 150 g of acetone, then dropped into 2,000 g of water to solidify, and the resulting white powder was filtered and filtered at 50 ° C. under reduced pressure. And dried overnight to obtain a polymer (A-2). The polymer (A-2) had Mw of 6,000 and Mw / Mn of 1.90. As a result of ¹³ C-NMR analysis, the content ratios of the structural unit derived from p-hydroxystyrene and the structural unit derived from the compound (M-1) were 50 mol% and 50 mol%, respectively.

[Synthesis Examples 3 and 4]
Polymers (A-3) and (A-4) were synthesized in the same manner as in Synthesis Example 2 except that the types and amounts of monomers shown in Table 1 were used. In Table 1, it shows together about Mw of each obtained polymer, Mw / Mn, and each structural unit content rate.

 

 

[Synthesis Example 5]
Glutaraldehyde (50% by mass aqueous solution) 10 g, 3-methoxyphenol 24.8 g and trifluoroacetic acid 37.5 g were dissolved in chloroform 50 mL and refluxed for 48 hours. This solution was added to methanol, and the deposited precipitate was vacuum-dried to obtain 11.3 g of the following monomolecule (M-8) protected with a methoxy group. Next, 8.0 g of this compound, 8.2 g of potassium carbonate, and 0.064 g of tetrabutylammonium bromide were dissolved in 95 mL of N-methylpyrrolidone (NMP) and stirred at 60 ° C. for 3 hours. Further, a solution of 4.3 g of 2-bromoacetyloxy-2-methyladamantane and 5 mL of NMP was added, and the mixture was further stirred at 60 ° C. for 48 hours. The reaction solution was poured into chloroform, washed with a 0.1 M aqueous oxalic acid solution, dried over magnesium sulfate, filtered through celite, and the filtrate was concentrated under reduced pressure. The concentrated solution is added to methanol to precipitate a solid, which is dried under reduced pressure, whereby a compound (A-8) in which 18% of the hydroxyl group is protected with a 2-acetyloxy-2-methyladamantane group (A 5.9 g of -5) was obtained.

<Synthesis of [C] Compound>
[Synthesis Example 6]
Propylene glycol monomethyl ether acetate is added to 10 g of titanium (IV) tri-n-butoxide stearate (90% strength by weight butanol solution), and a solution containing [C] compound having a solid content concentration of 10% by weight (C-1 )

[Synthesis Example 7]
Propylene glycol monomethyl ether acetate is added to 10 g of titanium (IV), diisopropoxide, bisacetylacetonate (75% strength by weight isopropyl alcohol solution), and a solid content concentration of 10% by weight [C] compound-containing solution ( C-2) was obtained.

[Synthesis Example 8]
Propylene glycol monomethyl ether acetate is added to 10 g of zirconium (IV), tributoxide, acetylacetonate (50% by mass butyl acetate / n-butanol (mass ratio 60/40) solution), and the solid content concentration is 10% by mass. [C] Compound-containing solution (C-3) was obtained.

[Synthesis Example 9]
Dissolve 1.0 g of hafnium (IV) tetra-t-butoxide in 20 mL of tetrahydrofuran and add a solution of 0.6 g of 2,2-dimethyl-3,5-hexanedione and 5 mL of tetrahydrofuran at room temperature. did. After refluxing for 1 hour, the solvent was removed under reduced pressure to obtain a compound represented by the following formula (C-4). This compound was dissolved in propylene glycol acetate monomethyl ether to obtain a [C] compound-containing solution (C-4) having a solid content concentration of 10% by mass.

[Synthesis Example 10] 1.0 g of hafnium (IV) isopropoxide was dissolved in propylene glycol monomethyl ether acetate to obtain a [C] compound-containing solution (C-10) having a solid content concentration of 10% by mass.

[Synthesis Example 11]
6.5 g of tantalum (V) pentaphenoxide was dissolved in 80 mL of benzene, 1.4 g of o-hydroxyacetophenone was added thereto, refluxed for 6 hours, and then the solution was cooled to 0 ° C., whereupon a precipitate was deposited. . The precipitate was collected by filtration, washed with pentane, and dried to obtain a compound represented by the following formula (C-5). This compound was dissolved in propylene glycol acetate monomethyl ether to obtain a [C] compound-containing solution (C-5) having a solid content concentration of 10% by mass.

[Synthesis Example 12]
Dissolve 4.6 g of cyclopentadienyl tungsten (V) tetrachloride in 50 mL of diethyl ether, add 4.1 g of triethylamine and 4.9 g of 3,5-dimethylphenol, and stir at room temperature for 30 minutes. After that, the by-product salt was removed by filtration, and the filtrate was dried under reduced pressure. The resulting concentrate was dissolved in diethyl ether, and this was cooled and recrystallized, whereby the following formula (C-6) was obtained. The compound obtained was obtained. This compound was dissolved in propylene glycol acetate monomethyl ether to obtain a [C] compound-containing solution (C-6) having a solid concentration of 10% by mass.

[Synthesis Example 13]
4.1 g of tetra-t-butoxytin (IV) was dissolved in 50 mL of pyridine, 1.4 g of acetoxytrimethylsilane was added thereto, and the mixture was stirred at room temperature for 24 hours, and then the solvent was removed under reduced pressure. The mixture was heated to 0 ° C. and reacted for 3 hours. The obtained solid was recrystallized from pyridine to obtain a compound represented by the following formula (C-7). This compound was dissolved in propylene glycol acetate monomethyl ether to obtain a [C] compound-containing solution (C-7) having a solid concentration of 10% by mass.

[Synthesis Example 14]
Propylene glycol monomethyl ether acetate was added to 10 g of zirconium (IV) tetracarboxyethyl acrylate to obtain a metal compound solution (C-8) having a solid content concentration of 10% by mass.

[Synthesis Example 15]
Propylene glycol monomethyl ether acetate was added to 10 g of tin (IV) acetate to obtain a metal compound solution (C-9) having a solid content concentration of 10% by mass.

<Preparation of radiation-sensitive composition>
Each component other than the [A] polymer and the [C] compound used for the preparation of the radiation sensitive composition is shown below.

[[B] acid generator]
B-1: Triphenylsulfonium nonafluoro-n-butanesulfonate (compound represented by the following formula (B-1))
B-2: Triphenylsulfonium 2- (4-oxo-adamantan-1-ylcarbonyloxy) -1,1,3,3,3-pentafluoropropane-1-sulfonate (represented by the following formula (B-2) Compound)

[[D] acid diffusion controller]
D-1: Triphenylsulfonium salicylate (compound represented by the following formula (D-1))
D-2: 2,4,5-triphenylimidazole (compound represented by the following formula (D-2))

[[E] solvent]
E-1: Propylene glycol monomethyl ether acetate E-2: Ethyl lactate E-3: Cyclohexanone

[Example 1]
[A] 100 parts by mass of (A-1) as a polymer, [B] 27 parts by mass of (B-1) as an acid generator, [C] 50 parts by mass of a compound-containing solution (C-1) (solid content 5 parts by mass in terms of conversion), [D] 2.6 parts by mass of (D-1) as an acid diffusion controller, and (E-1) 4,300 parts by mass as (E) solvent and (E-2) 1,900 parts by mass were mixed, and the resulting mixture was filtered through a membrane filter having a pore size of 0.20 μm to prepare a radiation sensitive composition (R-2).

[Examples 2 to 8 and Comparative Examples 1 to 7]
Each radiation-sensitive composition was prepared in the same manner as in Example 1 except that the components of the types and amounts shown in Table 2 were used.

 

 

<Pattern formation>
[Example 1]
In the “Clean Track ACT-8” of Tokyo Electron Co., Ltd., the radiation sensitive composition (R-2) prepared in Example 1 was spin-coated on a silicon wafer, and then PB was formed at 110 ° C. for 60 seconds. And a resist film having an average thickness of 50 nm was formed. Subsequently, patterning was performed by irradiating an electron beam using a simple electron beam drawing apparatus (“HL800D” manufactured by Hitachi, Ltd., output: 50 KeV, current density: 5.0 ampere / cm ² ). After the electron beam irradiation, PEB was performed in the clean track ACT-8 at 100 ° C. for 60 seconds. After that, in the clean track ACT-8, using a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution and developing at 23 ° C. for 1 minute by the paddle method, washing with pure water and drying. A positive resist pattern was formed. Similar patterning was also performed with a vacuum ultraviolet exposure apparatus (NA: 0.3, dipole illumination). Process conditions other than exposure are the same as described above.

[Examples 2 to 6 and 8 and Comparative Examples 1 to 4 and 6]
Each resist pattern was formed in the same manner as in Example 1 except that the radiation-sensitive composition shown in Table 3 below was used. The positive resist pattern thus formed was evaluated for the sensitivity and nanoedge roughness shown below. The evaluation results are shown in Table 3.

[Example 7 and Comparative Example 5]
Except having used the radiation sensitive composition shown in following Table 3, it operated similarly to Example 1 to PEB. Next, development was performed by the paddle method at 23 ° C. for 1 minute using butyl acetate (AcOBu) in the clean track ACT-8, followed by drying to form a negative resist pattern. The resist pattern thus formed was evaluated for the sensitivity and nanoedge roughness shown below. The evaluation results are shown in Table 3.

<Evaluation>
[sensitivity]
By patterning with an electron beam drawing apparatus, a line-and-space pattern (1L1S) consisting of a line portion having a line width of 150 nm and a space portion having a spacing of 150 nm formed by adjacent line portions is set to a one-to-one line width. The exposure amount to be formed was the optimum exposure amount, and this optimum exposure amount was the sensitivity (μC / cm ² ). Sensitivity is less than 35μC / cm ² The "AA (very good)", when it is 35μC / cm ² or more 50 .mu.C / cm ² or less as "A (good)", if it exceeds 50 .mu.C / cm ² Was judged as “B (defect)”.

[Nano edge roughness (nm)]
The line pattern of the line and space pattern (1L1S) was observed with a high-resolution FEB length measuring device (“S-9220”, Hitachi, Ltd.) by patterning with an electron beam drawing device. Arbitrary 20 points in the substrate are observed, and as for the observed shape, as shown in FIG. 1 and FIG. 2, irregularities generated along the lateral surface 2a of the line part 2 of the resist film formed on the silicon wafer 1 The difference “ΔCD” between the line width at the most remarkable point and the design line width of 150 nm was measured, and the average value of this ΔCD was defined as nano edge roughness (nm). When the nano edge roughness (nm) is 15.0 nm or less, “AA (very good)”, and when it exceeds 15.0 nm and 16.5 nm or less, “A (good)” is 16.5 nm. When exceeding, it was judged as "B (defect)". In addition, the unevenness | corrugation shown in FIG.1 and FIG.2 is exaggerated rather than actually.

[Storage stability]
After the prepared radiation sensitive composition was stored at 40 ° C. for 3 months, a pattern formation test was performed by patterning with an electron beam drawing apparatus, and a line-and-space pattern (1L1S) having a line width of 150 nm was 1: 1. The amount of exposure formed on the line width was measured. The change in value of the exposure amount before storage and after storage for 3 months was used as an index of storage stability. The storage stability is “AA (very good)” when the change in exposure amount is less than 5%, “A (good)” when the change in exposure amount is 5% or more and 10% or less, and more than 10%. It was judged as “B (defect)”.

[Resolution in vacuum ultraviolet exposure]
Patterning by the vacuum ultraviolet exposure apparatus described above enabled formation of a line-and-space pattern (1L1S) including a line portion having a line width of 30 nm and a space portion having a space formed by the adjacent line portions having a space of 30 nm. The case was judged as “A (good)”, and the case where it was impossible was judged as “B (bad)”.

 

 

From the results of patterning by the electron beam drawing apparatus shown in Table 3, when a metal complex having an oxyhydrocarbon group as a ligand is added to the radiation-sensitive composition, the sensitivity is improved while maintaining or improving nanoedge roughness performance. In addition, it became clear that the limit resolution could be improved from the results of vacuum ultraviolet exposure patterning.

According to the radiation-sensitive composition and pattern formation method of the present invention, it is possible to form a pattern with small nanoedge roughness and excellent limit resolution while improving sensitivity and storage stability. Therefore, these can be suitably used for manufacturing semiconductor devices that are expected to be further miniaturized in the future.

1 Silicon wafer 2 Pattern line 2a Pattern side

Claims (12)

A polymer having a first structural unit containing an acid-dissociable group,
A radiation-sensitive composition comprising a radiation-sensitive acid generator and a compound represented by the following formula (1).

(In Formula (1), M is a metal atom. L is a ligand other than OR ^1. R ¹ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. X is Y is an integer of 0 to 5. y is an integer of 1 to 6. However, x + y is not more than 6. When x is 2 or more, a plurality of L may be the same or different. In the above case, the plurality of R ¹ may be the same or different.) The metal atom of M in the above formula (1) is Group 3, Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, Group 10, Group 11, Group 12 The radiation-sensitive composition according to claim 1, which is a group, group 13 or group 14 metal atom. The radiation-sensitive composition according to claim 2, wherein the metal atom is titanium, zirconium, hafnium, tantalum, tungsten or tin. The radiation-sensitive composition according to claim 1, 2 or 3, wherein x in the formula (1) is an integer of 1 to 5. 5. The method according to claim 1, wherein the first structural unit is a structural unit represented by the following formula (2-1), a structural unit represented by the following formula (2-2), or a combination thereof. The radiation-sensitive composition according to item 1.

(In the formula (2-1), R ² is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ³ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ⁴ And R ⁵ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a ring member having 3 to 20 ring members composed of these groups together with the carbon atom to which they are bonded. Represents an alicyclic structure.
In formula (2-2), R ⁶ represents a hydrogen atom or a methyl group. L ¹ is a single bond, —COO— or —CONH—. R ⁷ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ⁸ and R ⁹ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms or a monovalent oxyhydrocarbon group having 1 to 20 carbon atoms. ) The radiation sensitive composition according to any one of claims 1 to 5, wherein the polymer further has a second structural unit represented by the following formula (3).

(In Formula (3), R ¹⁵ represents a hydrogen atom or a methyl group. L ² represents a single bond or a divalent organic group having 1 to 20 carbon atoms. R ¹⁶ represents a carbon atom having 1 to 20 carbon atoms. A monovalent organic group, p is an integer of 0 to 2. q is an integer of 0 to 9. When q is 2 or more, a plurality of R ¹⁶ may be the same or different. r is an integer of 1 to 3.) The radiation-sensitive composition according to any one of claims 1 to 4, wherein the polymer is calixarene. The radiation sensitive composition according to any one of claims 1 to 7, wherein a content of the compound with respect to 100 parts by mass of the polymer is 0.1 parts by mass or more and 50 parts by mass or less. Forming a film;
A step of exposing the film; and a step of developing the exposed film,
The pattern formation method which forms the said film | membrane with the radiation sensitive composition of any one of Claim 1-8. The pattern forming method according to claim 9, wherein the developer used in the development step is an alkaline aqueous solution. The pattern forming method according to claim 9, wherein the developer used in the developing step is an organic solvent-containing solution. The pattern forming method according to claim 9, 10 or 11, wherein the radiation used in the exposure step is extreme ultraviolet rays or electron beams.

Images