TW202219079A - Radiation-sensitive resin composition, pattern forming method and onium salt compound - Google Patents

Abstract

A radiation-sensitive resin composition which exhibits sufficient sensitivity, LWR performance and CDU performance, a pattern forming method and an onium salt compound are provided. This radiation-sensitive resin composition comprises an onium salt compound represented by formula (1), a resin including a structural unit having an acid-dissociable group, and a solvent. (In formula (1), Rf represents a fluorine atom or a C1-10 monovalent fluorinated hydrocarbon group. Each of R1-R3 independently represents a hydrogen atom or a C1-20 monovalent hydrocarbon group having, or alternatively, two of R1 to R3 are combined with each other and represent a C3-20 ring structure configured together with a carbon atom where these bond together. n is an integer of 1-4. When n is 2 or more, the R2 and R3 groups are the same or different. Z+ represents a monovalent radiation-sensitive onium cation.).

Description

Radiation-sensitive resin composition, pattern forming method, and onium salt compound

The present invention relates to a radiation-sensitive resin composition, a pattern forming method and an onium salt compound.

A photolithography technique using a resist composition is used for fine circuit formation of semiconductor elements. As a typical procedure, for example, an acid is generated by exposing the film of the resist composition by irradiation with radiation through a mask pattern, and the exposed part and the unexposed part are reacted with the acid as a catalyst. A difference in the solubility of the resin with respect to an alkali-based or organic-based developer is generated during the process, whereby a resist pattern is formed on the substrate.

In the photolithography technique, short-wavelength radiation such as an ArF excimer laser or the like is used, or a liquid immersion immersion method is used to perform exposure in a state where the space between the lens and the resist film of the exposure device is filled with a liquid medium. Exposure method (liquid immersion lithography) to advance pattern miniaturization.

In an effort to promote further technological progress, a technique has been proposed: a quencher (diffusion control agent) is prepared in a resist composition, and the acid diffused to the unexposed part is captured by a salt exchange reaction, and the exposure based on ArF is improved. lithography performance (Patent Document 1). In addition, as a next-generation technology, lithography using shorter wavelength radiation such as electron beams, X-rays, and extreme ultraviolet (EUV) is also being studied. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 5556765

[The problem to be solved by the invention] In efforts for such next-generation technology, the performance of Line Width Roughness (LWR), which represents the variation in sensitivity or the line width of the resist pattern, as an index of the uniformity of the line width or aperture, is the key Dimensional uniformity (critical dimension uniformity, CDU) performance and other aspects require resist performance that is equal to or higher than that of the past. However, these characteristics cannot be obtained at a sufficient level with the existing radiation-sensitive resin composition.

An object of the present invention is to provide a radiation-sensitive resin composition, a pattern forming method, and an onium salt compound that can exhibit sensitivity, LWR performance, and CDU performance at a sufficient level. [Means of Solving Problems]

The inventors of the present invention made repeated efforts to solve the problem, and as a result, they found that the object can be achieved by adopting the following structure, and completed the present invention.

（所述式（1）中， R ^f為氟原子或碳數1～10的一價氟化烴基。 R ¹～R ³分別獨立地為氫原子或碳數1～20的一價烴基，或者表示R ¹～R ³中的兩個相互結合並與該些所鍵結的碳原子一起構成的碳數3～20的環狀結構。 n為1～4的整數。於n為2以上的情況下，多個R ²及R ³彼此相同或不同， Z ⁺為一價的感放射線性鎓陽離子）。 That is, one embodiment of the present invention relates to a radiation-sensitive resin composition comprising: an onium salt compound represented by the following formula (1) (hereinafter, also referred to as "onium salt compound (1)" ), a resin containing a structural unit having an acid dissociable group, and a solvent. [hua 1]

(In the above formula (1), R ^f is a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms. R ¹ to R ³ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, or Represents a cyclic structure having 3 to 20 carbon atoms in which two of R ¹ to R ³ are bonded to each other and together with these bonded carbon atoms. n is an integer of 1 to 4. When n is 2 or more In the following, a plurality of R ² and R ³ are the same or different from each other, and Z ⁺ is a monovalent radioactive onium cation).

Since the radiation-sensitive resin composition contains the onium salt compound (1) as a quencher (acid diffusion control agent), it can exhibit excellent sensitivity, LWR performance, and CDU performance when forming a resist pattern. The reason for this, although not limited by any theory, is presumed to be influenced by the fact that the onium salt compound (1) has high transparency (low absorption in the wavelength band of exposure) in the resist film, so that the sensitivity is good, At the same time, the fluorinated hydrocarbon group and the carboxylate anion are appropriately separated, and the number of the fluorinated hydrocarbon group is reduced to one (as a result, the carboxylate anion is destabilized and the hydroxyl group is stabilized), and the basicity of the onium salt compound (1) is relatively It is enhanced, and the acid capture property of the unexposed part becomes high.

In another embodiment, the present invention relates to a pattern forming method, the pattern forming method includes: a step of directly or indirectly coating the radiation-sensitive resin composition on a substrate to form a resist film; the step of exposing the resist film; and The step of developing the exposed resist film with a developing solution.

In this pattern forming method, since the radiation-sensitive resin composition excellent in sensitivity, LWR performance, and CDU performance is used, a high-quality resist pattern can be efficiently formed.

（所述式（1）中， R ^f為氟原子或碳數1～10的一價氟化烴基。 R ¹～R ³分別獨立地為氫原子或碳數1～20的一價烴基，或者表示R ¹～R ³中的兩個相互結合並與該些所鍵結的碳原子一起構成的碳數3～20的環狀結構。 n為1～4的整數。於n為2以上的情況下，多個R ²及R ³彼此相同或不同， Z ⁺為一價的感放射線性鎓陽離子）。 In still another embodiment, the present invention relates to an onium salt compound represented by the following formula (1) (ie, an onium salt compound (1)). [hua 2]

(In the above formula (1), R ^f is a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms. R ¹ to R ³ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, or Represents a cyclic structure having 3 to 20 carbon atoms in which two of R ¹ to R ³ are bonded to each other and together with these bonded carbon atoms. n is an integer of 1 to 4. When n is 2 or more In the following, a plurality of R ² and R ³ are the same or different from each other, and Z ⁺ is a monovalent radioactive onium cation).

The onium salt compound (1) exhibits transparency and strong alkalinity in a resist film, and therefore, when it is formulated into a radiation-sensitive resin composition, it can impart to the composition a resistance to resist pattern formation. Excellent sensitivity, or LWR performance, CDU performance.

Hereinafter, the embodiments of the present invention will be described in detail, but the present invention is not limited to these embodiments.

<Radiation sensitive resin composition> The radiation-sensitive resin composition (hereinafter, also simply referred to as "composition") of the present embodiment includes a predetermined onium salt compound (1), a resin, and a solvent. Furthermore, a radiation sensitive acid generator is contained as needed. As long as the effect of this invention is not impaired, the said composition may contain other arbitrary components. By including the predetermined onium salt compound (1) in the radiation-sensitive resin composition, high-level sensitivity, LWR performance, and CDU performance can be imparted to the radiation-sensitive resin composition.

(Onium salt compound (1)) The onium salt compound (1) functions as a quencher (also referred to as a "photodegradable base" or "acid diffusion controller") that captures an acid in a pre-exposed or unexposed portion. The onium salt compound (1) is represented by the following formula (1).

（所述式（1）中， R ^f為氟原子或碳數1～10的一價氟化烴基。 R ¹～R ³分別獨立地為氫原子或碳數1～20的一價烴基，或者表示R ¹～R ³中的兩個相互結合並與該些所鍵結的碳原子一起構成的碳數3～20的環狀結構。 n為1～4的整數。於n為2以上的情況下，多個R ²及R ³彼此相同或不同， Z ⁺為一價的感放射線性鎓陽離子）。 [hua 3]

(In the above formula (1), R ^f is a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms. R ¹ to R ³ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, or Represents a cyclic structure having 3 to 20 carbon atoms in which two of R ¹ to R ³ are bonded to each other and together with these bonded carbon atoms. n is an integer of 1 to 4. When n is 2 or more In the following, a plurality of R ² and R ³ are the same or different from each other, and Z ⁺ is a monovalent radioactive onium cation).

In the above formula (1), examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ^f include: a monovalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms, Monovalent fluorinated alicyclic hydrocarbon group, etc.

Examples of the monovalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms include: Trifluoromethyl, 2,2,2-trifluoroethyl, pentafluoroethyl, 2,2,3,3,3-pentafluoropropyl, 1,1,1,3,3,3-hexafluoro Propyl, heptafluoro-n-propyl, heptafluoroisopropyl, nonafluoro-n-butyl, nonafluoroisobutyl, nonafluorotert-butyl, 2,2,3,3,4,4,5,5- Fluorinated alkyl groups such as octafluoro-n-pentyl, tridecafluoro-n-hexyl, 5,5,5-trifluoro-1,1-diethylpentyl; Fluorinated alkenyl such as trifluorovinyl and pentafluoropropenyl; Fluorinated alkynyl groups such as fluoroethynyl, trifluoropropynyl, and the like.

Examples of the monovalent fluorinated alicyclic hydrocarbon group having 3 to 20 carbon atoms include: Fluorocyclopentyl, difluorocyclopentyl, nonafluorocyclopentyl, fluorocyclohexyl, difluorocyclohexyl, undecafluorocyclohexylmethyl, fluoronorbornyl, fluoroadamantyl, fluorobornyl, fluoroiso Fluorinated cycloalkyl groups such as bornyl, fluorotricyclodecyl, and fluorotetracyclodecyl; Fluorinated cycloalkenyl such as fluorocyclopentenyl, nonafluorocyclohexenyl, etc.

The fluorinated hydrocarbon group is preferably the monovalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms, more preferably a monovalent fluorinated alkyl group having 1 to 10 carbon atoms, and still more preferably a monovalent fluorinated alkyl group having 1 to 6 carbon atoms. The perfluoroalkyl group is particularly preferably a linear perfluoroalkyl group having 1 to 6 carbon atoms.

The monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ¹ , R ² and R ³ in the formula (1) is not particularly limited, and examples thereof include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, or A monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and the like.

Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include a linear or branched saturated hydrocarbon group having 1 to 20 carbon atoms, or a linear or branched unsaturated hydrocarbon group having 1 to 20 carbon atoms. .

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include a monocyclic or polycyclic saturated hydrocarbon group, or a monocyclic or polycyclic unsaturated hydrocarbon group. The monocyclic saturated hydrocarbon group is preferably a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. The polycyclic cycloalkyl group is preferably a bridged alicyclic hydrocarbon group such as norbornyl, adamantyl, tricyclodecyl, and tetracyclododecyl. Examples of the monocyclic unsaturated hydrocarbon group include monocyclic cycloalkenyl groups such as a cyclopropenyl group, a cyclobutenyl group, a cyclopentenyl group, and a cyclohexenyl group. Examples of the polycyclic unsaturated hydrocarbon group include polycyclic cycloalkenyl groups such as norbornenyl, tricyclodecenyl, and tetracyclododecenyl. In addition, the bridged alicyclic hydrocarbon group refers to a polycyclic alicyclic hydrocarbon group in which two carbon atoms which are not adjacent to each other among the carbon atoms constituting the alicyclic ring are bonded by a bonding chain containing one or more carbon atoms.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include aryl groups such as phenyl, tolyl, xylyl, naphthyl, and anthracenyl; aromatic groups such as benzyl, phenethyl, and naphthylmethyl. Alkyl etc.

Examples of the cyclic structure having 3 to 20 carbon atoms in which two of R ¹ to R ³ are bonded to each other and constituted together with the bonded carbon atoms include the monovalent alicyclic having 3 to 20 carbon atoms described above. A structure obtained by further removing a hydrogen atom from a hydrocarbyl group of the formula.

From the viewpoint of increasing the basicity of the onium salt compound (1) to efficiently control the diffusion of the acid, n in the formula (1) is an integer of 1 or more to suppress the generation of electron-withdrawing fluorinated hydrocarbon groups. stabilization of the carboxylate anion.

On the other hand, when the basicity of the onium salt compound (1) is too high, it is difficult to stably exist as a salt, so the above formula (1) Among them, n is preferably an integer of 1 to 3, more preferably 1 or 2, particularly preferably 1.

In addition, from the viewpoint of keeping the basicity and structure of the onium salt compound (1) constant, in order to form only a specific intramolecular hydrogen bond, R ^f and R ¹ to R in the above formula (1) are preferably None of the ³ contained hydroxyl groups (ie, the anionic moiety had only one hydroxyl group).

Although it does not specifically limit as an anion part of the onium salt compound (1) represented by the said formula (1), For example, the structure etc. which are represented by following formula (1a) - formula (1z) are mentioned.

[hua 4]

[hua 5]

[hua 6]

In the formula (1), the monovalent radioactive onium cation represented by Z ⁺ includes, for example, S, I, O, N, P, Cl, Br, F, As, Se, Sn Examples of radiation-decomposable onium cations of elements such as Sb, Te, and Bi include perionium cations, tetrahydrothiophenium cations, iodonium cations, phosphonium cations, diazonium cations, and pyridinium cations. Among them, pericynium cation or iodonium cation is preferable. The periconium cation or the iodonium cation is preferably represented by the following formulae (X-1) to (X-6).

[hua 7]

[hua 8]

[Chemical 9]

[Chemical 10]

[Chemical 11]

[Chemical 12]

In the formula (X-1), R ^a1 , R ^a2 and R ^a3 are each independently a substituted or unsubstituted linear or branched alkyl group, alkoxy group or alkane having 1 to 12 carbon atoms Oxycarbonyloxy, substituted or unsubstituted monocyclic or polycyclic cycloalkyl group with 3 to 12 carbon atoms, substituted or unsubstituted aromatic hydrocarbon group with 6 to 12 carbon atoms, hydroxyl group, halogen atom , -OSO ₂ -R ^P , -SO ₂ -R ^Q or -SR ^T , or a ring structure formed by combining two or more of these groups. The ring structure may contain heteroatoms such as O or S between carbon-carbon bonds forming the skeleton. R ^P , R ^Q and R ^T are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alicyclic having 5 to 25 carbon atoms. A hydrocarbon group of the formula or a substituted or unsubstituted aromatic hydrocarbon group with 6 to 12 carbon atoms. k1, k2, and k3 are each independently an integer of 0-5. When there are multiple R ^a1 to R ^a3 and R ^P , R ^Q and ^RT respectively, the multiple R ^a1 to R ^a3 and R ^P , R ^Q and RT may be the same or different, respectively ^.

In the formula (X-2), R ^b1 is a substituted or unsubstituted linear or branched alkyl group or alkoxy group with 1 to 20 carbon atoms, a substituted or unsubstituted carbon number with 2 -8 acyl group, or substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms, or hydroxy group. n _k is 0 or 1. When n _k is 0, k4 is an integer of 0-4, and when n _k is 1, k4 is an integer of 0-7. When there are plural R ^b1s , the plural R ^b1s may be the same or different, and the plural R ^b1s may represent a ring structure formed by bonding 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. L ^C is a single bond or a divalent linking group. k5 is an integer of 0-4. When there are plural R ^b2s , the plural R ^b2s may be the same or different, and the plural R ^b2s may represent a ring structure formed by bonding with each other. q is an integer of 0-3. In the formula, the ring structure containing S ⁺ may contain heteroatoms such as O or S between carbon-carbon bonds forming the skeleton.

In the formula (X-3), R ^c1 , R ^c2 and R ^c3 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms.

In the formula (X-4), R ^g1 is a substituted or unsubstituted linear or branched alkyl group having 1 to 20 carbon atoms or an alkoxy group, a substituted or unsubstituted carbon number 2 -8 acyl group, or substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms, or hydroxy group. n _k2 is 0 or 1. When n _k2 is 0, k10 is an integer of 0 to 4, and when n _k2 is 1, k10 is an integer of 0 to 7. When there are plural R ^g1s , the plural R ^g1s may be the same or different, and the plural R ^g1s may represent a ring structure formed by bonding with each other. R ^g2 and R ^g3 are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, an alkoxy group or an alkoxycarbonyloxy group, a substituted or unsubstituted A monocyclic or polycyclic cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, a hydroxyl group, a halogen atom, or a ring structure formed by combining these groups with each other . k11 and k12 are each independently an integer of 0 to 4. When each of R ^g2 and R ^g3 is plural, the plural R ^g2 and R ^g3 may be the same or different, respectively.

In the formula (X-5), R ^d1 and R ^d2 are each independently a substituted or unsubstituted linear or branched alkyl group, alkoxy group or alkoxycarbonyl group having 1 to 12 carbon atoms , substituted or unsubstituted aromatic hydrocarbon groups with 6 to 12 carbon atoms, halogen atoms, halogenated alkyl groups with 1 to 4 carbon atoms, nitro groups, or a ring formed by combining two or more of these groups with each other structure. k6 and k7 are each independently an integer of 0 to 5. When each of R ^d1 and R ^d2 is plural, the plural R ^d1 and R ^d2 may be the same or different, respectively.

In the formula (X-6), R ^e1 and R ^e2 are each independently a halogen atom, a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted alkyl group. A substituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k8 and k9 are each independently an integer of 0-4.

The onium salt compound (1) is formed by any combination of the anion moiety defined by the formula (1) and the monovalent radiosensitive onium cation. Although it does not specifically limit as a specific example of an onium salt compound (1), For example, the structure etc. which are represented by following formula (1-1) - formula (1-26) are mentioned.

[Chemical 13]

[Chemical 14]

[Chemical 15]

[Chemical 16]

Among them, the above-mentioned formula (1-1), formula (1-4), formula (1-5), formula (1-7) to formula (1-20), formula (1-23) to formula are preferred The onium salt compound (1) represented by (1-25).

The content of the onium salt compound (1) in the radiation-sensitive resin composition of the present embodiment (in the case of using a plurality of types of onium salt compounds in combination, the total of each) is preferably 0.01 part by mass relative to 100 parts by mass of the resin described later. more than 30 parts by mass or less. The content is more preferably 25 parts by mass or less, still more preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less. In addition, the content is more preferably 0.05 part by mass or more, still more preferably 0.1 part by mass or more, and particularly preferably 0.5 part by mass or more. The content of the onium salt compound (1) is appropriately selected depending on the type of resin to be used, exposure conditions or required sensitivity, and the type and content of the radiation-sensitive acid generator described later. Thereby, excellent sensitivity, LWR performance, and CDU performance can be exhibited when forming a resist pattern.

(Synthesis method of onium salt compound (1)) As the onium salt compound (1), the case where all of R ¹ to R ³ are hydrogen atoms and n is 1 will be described as an example. Typically, as shown in the following scheme, the ketone of the fluorinated ketone ester is converted into an alcohol with a reducing agent (sodium borohydride as a hydride complex in the scheme), and then the ester moiety is hydrolyzed with a base. , and finally react with an onium cation halide corresponding to the onium cation moiety to perform salt exchange, whereby the target onium salt compound (1) can be synthesized.

（式中，R ¹及Z ⁺與所述式（1）為相同含義。M為鹼金屬。Hal ^-是鹵化物離子。） [Chemical 17]

(In the formula, R ¹ and Z ⁺ have the same meanings as in the above formula (1). M is an alkali metal. Hal ^- is a halide ion.)

The onium salt compound (1) having another structure can also be synthesized similarly by appropriately selecting the fluorinated ketone ester or reducing agent serving as the base of the anion moiety, and a precursor corresponding to the onium cation moiety. For example, a hydrocarbyl group can be introduced as R ¹ by using a Grignard reagent in place of a hydride complex as a ketone reducing agent.

(resin) The resin is an aggregate of polymers having a structural unit (hereinafter, also referred to as "structural unit (I)") containing an acid dissociable group (hereinafter, this resin is also referred to as "base resin"). The "acid-dissociable group" refers to a group that substitutes a hydrogen atom contained in a carboxyl group, a phenolic hydroxyl group, an alcoholic hydroxyl group, a sulfo group, and the like, and is a group that is dissociated by the action of an acid. The radiation-sensitive resin composition has the structural unit (I) due to the resin, and is excellent in pattern formability.

In addition to the structural unit (I), the base resin preferably also has a structural unit (II) including at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure, which will be described later, You may have other structural units other than the structural unit (I) and the structural unit (II). Hereinafter, each structural unit will be described.

[Structural unit (I)] The structural unit (I) is a structural unit containing an acid dissociable group. The structural unit (I) is not particularly limited as long as it contains an acid dissociable group, and examples thereof include a structural unit having a tertiary alkyl ester moiety, and a structure in which a hydrogen atom having a phenolic hydroxyl group is substituted with a tertiary alkyl group. A structural unit, a structural unit having an acetal bond, etc., is preferably a structural unit represented by the following formula (3) (hereinafter, also referred to as the is "structural unit (I-1)").

[Chemical 18]

In the formula (3), R ⁷ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ⁸ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ⁹ and R ¹⁰ are each independently a monovalent chain hydrocarbon group having 1 to ¹⁰ carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or represent that these groups are bonded to each other and to the A divalent alicyclic group with 3 to 20 carbon atoms formed by carbon atoms together.

As said R< ⁷ >, from a viewpoint of the copolymerizability of the monomer which provides a structural unit (I-1), a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ⁸ include a chain hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms. The monovalent aromatic hydrocarbon group, etc.

Examples of the chain hydrocarbon group having ¹ to ¹⁰ carbon atoms represented by R ⁸ to R 10 include a linear or branched saturated hydrocarbon group having 1 to 10 carbon atoms, or a linear or branched hydrocarbon group having 1 to 10 carbon atoms. Chain unsaturated hydrocarbon group.

Examples of the alicyclic hydrocarbon group having 3 to ²⁰ carbon atoms represented by R ⁸ to R ¹⁰ include a monocyclic or polycyclic saturated hydrocarbon group, or a monocyclic or polycyclic unsaturated hydrocarbon group. The monocyclic saturated hydrocarbon group is preferably a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. The polycyclic cycloalkyl group is preferably a bridged alicyclic hydrocarbon group such as norbornyl, adamantyl, tricyclodecyl, and tetracyclododecyl. In addition, the bridged alicyclic hydrocarbon group refers to a polycyclic alicyclic hydrocarbon group in which two carbon atoms which are not adjacent to each other among the carbon atoms constituting the alicyclic ring are bonded by a bonding chain containing one or more carbon atoms.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by R ⁸ include: aryl groups such as phenyl, tolyl, xylyl, naphthyl, and anthracenyl; benzyl, phenethyl, etc. , naphthylmethyl and other aralkyl groups, etc.

The R ⁸ is preferably a linear or branched saturated hydrocarbon group having 1 to 10 carbon atoms, or an alicyclic hydrocarbon group having 3 to 20 carbon atoms.

The divalent alicyclic group having 3 to ²⁰ carbon atoms in which the chain hydrocarbon groups or alicyclic hydrocarbon groups represented by R ⁹ and R ¹⁰ are bonded to each other and constituted together with these bonded carbon atoms may be self-constituting. The group obtained by removing two hydrogen atoms from the same carbon atom of the carbon ring of the monocyclic or polycyclic alicyclic hydrocarbon having the carbon number is not particularly limited. It can be either a monocyclic hydrocarbon group or a polycyclic hydrocarbon group. The polycyclic hydrocarbon group can be either a bridged alicyclic hydrocarbon group or a condensed alicyclic hydrocarbon group, or a saturated hydrocarbon group or an unsaturated hydrocarbon group. A sort of. In addition, the condensed alicyclic hydrocarbon group refers to a polycyclic alicyclic hydrocarbon group constituted by a plurality of alicyclic rings sharing a side (a bond between two adjacent carbon atoms).

The saturated hydrocarbon group in the monocyclic alicyclic hydrocarbon group is preferably cyclopentanediyl, cyclohexanediyl, cycloheptanediyl, cyclooctanediyl and the like, and the unsaturated hydrocarbon group is preferably cyclopentanediyl Alkenediyl, cyclohexenediyl, cycloheptenediyl, cyclooctenediyl, cyclodecenediyl, etc. The polycyclic alicyclic hydrocarbon group is preferably a bridged alicyclic saturated hydrocarbon group, for example, bicyclo[2.2.1]heptane-2,2-diyl (norbornane-2,2-diyl) is preferred ), bicyclo[2.2.2]octane-2,2-diyl, tricyclo[3.3.1.1 ^3,7 ]decane-2,2-diyl (adamantane-2,2-diyl), etc.

Among these, it is preferable that R ⁸ is an alkyl group having 1 to 4 carbon atoms, and the alicyclic structure formed by R ⁹ and R ^{1 0} combined with each other and these bonded carbon atoms is polycyclic or monocyclic Cycloalkane structure.

As the structural unit (I-1), for example, structural units represented by the following formulae (3-1) to (3-6) (hereinafter, also referred to as "structural unit (I-1-1) to unit (I-1-6)”), etc.

[Chemical 19]

In the above formulas (3-1) to (3-6), R ⁷ to R ^{1 0} have the same meanings as in the above formula (3). i and j are each independently an integer of 1 to 4. k and l are 0 or 1.

As i and j, 1 is preferable. As R ⁸ , methyl, ethyl or isopropyl is preferred. As R ⁹ and R ¹⁰ , a methyl group or an ^ethyl group is preferable.

The base resin may contain one kind or two or more kinds of structural units (I) in combination.

With respect to all the structural units constituting the base resin, the content ratio of the structural unit (I) (the total content ratio when multiple types are included) is preferably 10 mol % or more, more preferably 20 mol % or more, and still more preferably It is 30 mol% or more, particularly preferably 35 mol% or more. In addition, it is preferably 80 mol % or less, more preferably 75 mol % or less, still more preferably 70 mol % or less, and particularly preferably 65 mol % or less. By making the content ratio of a structural unit (I) into the said range, the pattern formability of this radiation sensitive resin composition can be improved further.

[Structural unit (II)] The structural unit (II) is a structural unit containing at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure. Since the base resin further has the structural unit (II), the solubility to the developer can be adjusted, and as a result, the radiation-sensitive resin composition can improve lithography performance such as resolution. Moreover, the adhesiveness of the resist pattern formed with the base resin and a board|substrate can be improved.

As a structural unit (II), the structural unit etc. which are represented by following formula (T-1) - formula (T-10) are mentioned, for example.

[hua 20]

In the formula, R ^L1 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^L2 to R ^L5 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a cyano group, a trifluoromethyl group, a methoxy group, a methoxycarbonyl group, a hydroxyl group, a hydroxymethyl group, and a dimethylamino group. R ^L4 and R ^L5 may be a divalent alicyclic group having 3 to 8 carbon atoms which are bonded to each other and constituted together with these bonded carbon atoms. L ² is a single bond or a divalent linking group. X is an oxygen atom or a methylene group. k is an integer of 0-3. m is an integer of 1-3.

Examples of the divalent alicyclic group having 3 to 8 carbon atoms in which the R ^L4 and R ^L5 are bonded to each other and constituted together with the bonded carbon atoms include R ⁹ and R in the above formula (3). A group having 3 to 8 carbon atoms among the divalent alicyclic groups having 3 to 20 carbon atoms in which the chain hydrocarbon group or alicyclic hydrocarbon group represented by ^{1 0} is bonded to each other and constituted together with the bonded carbon atoms. One or more hydrogen atoms on the alicyclic group may be substituted with a hydroxyl group.

Examples of the divalent linking group represented by L ² include a divalent linear or branched hydrocarbon group having 1 to 10 carbon atoms, a divalent alicyclic hydrocarbon group having 4 to 12 carbon atoms, or A group consisting of one or more of these hydrocarbon groups and at least one of -CO-, -O-, -NH-, and -S-, and the like.

As the structural unit (II), among these, a structural unit containing a lactone structure is preferable, a structural unit containing a norbornane lactone structure is more preferable, and a norbornane lactone derived (meth)acrylate is further preferable. - Structural unit of base ester.

The content ratio of the structural unit (II) is preferably 20 mol % or more, more preferably 25 mol % or more, and still more preferably 30 mol % or more with respect to all the structural units constituting the base resin. In addition, it is preferably 80 mol % or less, more preferably 75 mol % or less, still more preferably 70 mol % or less. By setting the content ratio of the structural unit (II) to the above-mentioned range, the radiation-sensitive resin composition can further improve the lithography performance such as resolution and the adhesion between the formed resist pattern and the substrate.

[Structural unit (III)] The base resin optionally has other structural units in addition to the structural unit (I) and the structural unit (II). As said other structural unit, the structural unit (III) containing a polar group etc. are mentioned, for example (however, the thing corresponding to a structural unit (II) is excluded). By having the structural unit (III) more, the base resin can adjust the solubility to the developing solution, and as a result, can improve the lithography performance such as the analytical properties of the radiation-sensitive resin composition. As said polar group, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, a sulfonamido group etc. are mentioned, for example. Among these, a hydroxyl group and a carboxyl group are preferable, and a hydroxyl group is more preferable.

As a structural unit (III), the structural unit etc. which are represented by the following formula are mentioned, for example.

[Chemical 21]

In the formula, ^RA is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

When the base resin contains the structural unit (III) having a polar group, the content of the structural unit (III) is preferably 5 mol % or more relative to all the structural units constituting the base resin, More preferably, it is 8 mol % or more, and still more preferably 10 mol % or more. In addition, it is preferably 40 mol % or less, more preferably 35 mol % or less, still more preferably 30 mol % or less. By setting the content ratio of the structural unit (III) to the above-mentioned range, the lithography performance such as the resolution of the radiation-sensitive resin composition can be further improved.

[Structural Unit (IV)] As other structural units, in addition to the structural unit (III) having a polar group, the base resin optionally has a structural unit derived from hydroxystyrene or a structural unit having a phenolic hydroxyl group (hereinafter, both are also referred to together). "Structural Unit (IV)"). The structural unit (IV) contributes to the improvement of etching resistance and the improvement of the difference in developer solubility (dissolution contrast) between the exposed part and the unexposed part. In particular, it can be preferably applied to pattern formation using exposure with radiation having a wavelength of 50 nm or less, such as electron beams or EUV. In this case, it is preferable that resin has a structural unit (IV) and a structural unit (I) together.

In this case, it is preferable to carry out the polymerization in a state in which the phenolic hydroxyl group is protected by a protecting group such as an alkali dissociable group during the polymerization, and then hydrolyze and deprotect, whereby the structural unit (IV) is obtained. The structural unit which provides the structural unit (IV) by hydrolysis is preferably represented by the following formula (4-1) and formula (4-2).

[Chemical 22]

In the formula (4-1) and formula (4-2), R ^{1 1} is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^{1 2} is a monovalent hydrocarbon group or an alkoxy group having 1 to 20 carbon atoms. Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms in R ^{1 2} include monovalent hydrocarbon groups having 1 to 20 carbon atoms in R ⁸ in the structural unit (I). As an alkoxy group, a methoxy group, an ethoxy group, a 3rd butoxy group, etc. are mentioned, for example.

The R ^{1 2} is preferably an alkyl group and an alkoxy group, and more preferably a methyl group and a tertiary butoxy group.

In the case of a resin for exposure by radiation with a wavelength of 50 nm or less, the content ratio of the structural unit (IV) is preferably 10 mol % or more, more preferably 20 mol % with respect to all the structural units constituting the resin. %above. In addition, it is preferably 70 mol % or less, more preferably 60 mol % or less.

(Synthesis method of base resin) The base resin can be synthesized by, for example, polymerizing a monomer that provides each structural unit in an appropriate solvent using a radical polymerization initiator or the like.

Examples of the radical polymerization initiator include: azobisisobutyronitrile (AIBN), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) , 2,2'-azobis(2-cyclopropylpropanenitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyric acid Azo radical initiators such as dimethyl ester; peroxide radical initiators such as benzyl peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, etc. Among these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferable, and AIBN is more preferable. These radical initiators may be used alone or in combination of two or more.

Examples of the solvent used in the polymerization include: n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane and other alkanes; Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane; Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene; Halogenated hydrocarbons such as chlorobutane, bromohexane, dichloroethane, hexamethylene dibromide, and chlorobenzene; Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, isobutyl acetate, methyl propionate; Acetone, methyl ethyl ketone, 4-methyl-2-pentanone, 2-heptanone and other ketones; Ethers such as tetrahydrofuran, dimethoxyethane, and diethoxyethane; Alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 4-methyl-2-pentanol, etc. These solvents used for the polymerization may be used alone or in combination of two or more.

The reaction temperature in the polymerization is usually 40°C to 150°C, preferably 50°C to 120°C. The reaction time is usually 1 hour to 48 hours, preferably 1 hour to 24 hours.

The molecular weight of the base resin is not particularly limited, and the polystyrene-equivalent weight average molecular weight (Mw) by Gel Permeation Chromatography (GPC) is preferably 1,000 or more and 50,000 or less, more preferably 2,000 or more and 30,000 or less, more preferably 3,000 or more and 15,000 or less, and particularly preferably 4,000 or more and 12,000 or less. If the Mw of the base resin is less than the lower limit, the heat resistance of the obtained resist film may decrease. When Mw of a base resin exceeds the said upper limit, the developability of a resist film may fall.

The ratio (Mw/Mn) of Mw of the base resin to the number average molecular weight (Mn) in terms of polystyrene by GPC is usually 1 or more and 5 or less, preferably 1 or more and 3 or less, and more preferably 1 or more, 2 or less.

The Mw and Mn of resin in this specification are values measured using gel permeation chromatography (GPC) under the following conditions.

GPC columns: 2 G2000HXL, 1 G3000HXL, 1 G4000HXL (the above are manufactured by Tosoh) Column temperature: 40℃ Dissolution solvent: tetrahydrofuran Flow rate: 1.0 mL/min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Detector: Differential Refractometer Standard material: monodisperse polystyrene

The content of the base resin is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 85% by mass or more with respect to the total solid content of the radiation-sensitive resin composition.

(other resins) The radiation-sensitive resin composition of the present embodiment may contain, as another resin, a resin having a larger mass content of fluorine atoms than the base resin (hereinafter, also referred to as a "high fluorine content resin"). In the case where the radiation-sensitive resin composition contains a resin with a high fluorine content, it can be biased to exist in the surface layer of the resist film relative to the base resin, and as a result, the resistance of the resist film during immersion exposure can be improved. Water repellency of the surface.

The high fluorine content resin preferably has, for example, a structural unit represented by the following formula (5) (hereinafter, also referred to as "structural unit (V)"), and may have a structural unit in the base resin as necessary (I) or structural unit (II).

[Chemical 23]

In the formula (5), R ^{1 3} is a hydrogen atom, a methyl group or a trifluoromethyl group. GL is a single bond, an oxygen atom, a sulfur atom, -COO-, -SO ₂ ^ONH- , -CONH- or -OCONH-. R ^{1 4} is a monovalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated alicyclic hydrocarbon group having 3 to 20 carbon atoms.

As said R13, ^a hydrogen atom and a methyl group are preferable from a viewpoint of the copolymerizability ^of the monomer which provides a structural unit (V), and a methyl group is more preferable.

As said GL, a single bond and -COO- are preferable from a viewpoint of providing the copolymerizability of the monomer of a structural unit (V), and ^-COO- is more preferable.

Examples of the monovalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms represented by R ^{1 4} include a part or all of the hydrogen atoms contained in the straight-chain or branched alkyl group having 1 to 20 carbon atoms, which are fused to a fluorine atom. replaced by.

As the monovalent fluorinated alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ^{1 4} , a part or all of the hydrogen atoms contained in the monocyclic or polycyclic hydrocarbon group having 3 to 20 carbon atoms are fluorinated. Atom replacement.

The R ^{1 4} is preferably a fluorinated chain hydrocarbon group, more preferably a fluorinated alkyl group, and still more preferably 2,2,2-trifluoroethyl, 1,1,1,3,3,3- Hexafluoropropyl and 5,5,5-trifluoro-1,1-diethylpentyl.

When the high fluorine content resin has a structural unit (V), the content ratio of the structural unit (V) is preferably 30 mol % or more, more preferably 40 mol % with respect to all the structural units constituting the high fluorine content resin % or more, more preferably 45 mol % or more, and particularly preferably 50 mol % or more. In addition, it is preferably 95 mol % or less, more preferably 90 mol % or less, and still more preferably 85 mol % or less. By setting the content ratio of the structural unit (V) to the above-mentioned range, the mass content ratio of fluorine atoms in the resin with high fluorine content can be adjusted more appropriately, and the biased existence in the surface layer of the resist film can be further promoted, as a result. , the water repellency of the resist film during liquid immersion exposure can be further improved.

The high fluorine content resin may have a fluorine atom-containing structural unit (hereinafter, also referred to as a structural unit (VI) represented by the following formula (f-2) together with the structural unit (V) or in place of the structural unit (V). )). Since the high fluorine content resin has the structural unit (f-2), the solubility to an alkaline developer can be improved, and the occurrence of development defects can be suppressed.

[Chemical 24]

The structural unit (VI) is roughly classified into those having (x) an alkali-soluble group, and those having (y) a group that is dissociated by the action of an alkali and has increased solubility in an alkaline developer (hereinafter, also abbreviated as "alkali"). dissociative base") in both cases. Both (x) and (y) are common, and in the formula (f-2), R ^C is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^D is a single bond, a (s+1)-valent hydrocarbon group having 1 to 20 carbon atoms, and an oxygen atom, sulfur atom, -NR ^dd -, carbonyl group, -COO- or - is bonded to the terminal on the R ^E side of the hydrocarbon group A structure formed of CONH- or a structure in which a part of hydrogen atoms contained in the hydrocarbon group is substituted with an organic group having a hetero atom. R ^dd is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. s is an integer of 1-3.

When the structural unit (VI) has (x) an alkali-soluble group, RF is an oxygen atom and ^{A 1} is an oxygen atom, -COO-* or -SO ₂ O-*. * ^Indicates the site bound to RF. W ¹ is a single bond, a hydrocarbon group having 1 to 20 carbon atoms or a divalent fluorinated hydrocarbon group. When A ¹ is an oxygen atom, W ¹ is a fluorinated hydrocarbon group having a fluorine atom or a fluoroalkyl group on the carbon atom to which A ¹ is bonded. R ^E is a single bond or a divalent organic group having 1 to 20 carbon atoms. When s is 2 or 3, a plurality of RE, ^{W 1} , ^{A 1} and RF may be the same or different, respectively. By having (x) an alkali-soluble group in the structural unit (VI), the affinity for an alkaline developer can be improved and development defects can be suppressed. The structural unit (VI) having (x) an alkali-soluble group is particularly preferably one in which A ¹ is an oxygen atom and W ¹ is 1,1,1,3,3,3-hexafluoro-2,2-methanediyl. Happening.

When the structural unit (VI) has a base dissociable group (y), R ^F is a monovalent organic group having 1 to 30 carbon atoms, and A ¹ is an oxygen atom, -NR ^aa -, -COO-* or -SO2O -*. R ^aa is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. * ^Indicates the site bound to RF. W1 is a single bond or a divalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. R ^E is a single bond or a divalent organic group having 1 to 20 carbon atoms. When A ¹ is -COO-* or -SO ₂ O-*, a fluorine atom is present on the carbon atom to which W ¹ or R ^F is bonded to A ¹ or a carbon atom adjacent thereto. When A ¹ is an oxygen atom, W ¹ and R ^E are a single bond, R ^D is a structure in which a carbonyl group is bonded to the terminal on the R ^E side of a hydrocarbon group having 1 to 20 carbon atoms, and R ^F is a structure having fluorine. The organic radical of an atom. When s is 2 or 3, a plurality of RE, ^{W 1} , ^{A 1} and RF may be the same or different, respectively. Since the structural unit (VI) has (y) an alkali dissociable group, in the alkali development step, the surface of the resist film is changed from hydrophobicity to hydrophilicity. As a result, the affinity for the developer can be greatly improved, and development defects can be suppressed more efficiently. As a structural unit (VI) which has a base dissociable group (y), A ¹ is -COO-*, and it is especially preferable that R ^F or W ¹ or both have a fluorine atom.

As R ^C , a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable from the viewpoint of the copolymerizability of the monomer which provides the structural unit (VI).

When ^RE is a divalent organic group, it is preferably a group having a lactone structure, more preferably a group having a polycyclic lactone structure, and still more preferably a group having a norbornane lactone structure.

When the high fluorine content resin has a structural unit (VI), the content ratio of the structural unit (VI) is preferably 50 mol % or more, more preferably 60 mol % with respect to all the structural units constituting the high fluorine content resin % or more, more preferably 70 mol % or more. In addition, it is preferably 95 mol % or less, more preferably 90 mol % or less, and still more preferably 85 mol % or less. By setting the content ratio of the structural unit (VI) to the above range, the water repellency of the resist film at the time of liquid immersion exposure can be further improved.

（所述式（6）中，R ^1α為氫原子、氟原子、甲基或三氟甲基。R ^2α為碳數3～20的一價脂環式烴基。） [Other Structural Units] The high fluorine-content resin may contain, as structural units other than those listed above, a structural unit having an alicyclic structure represented by the following formula (6). [Chemical 25]

(In the above formula (6), R ^1α is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^2α is a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms.)

In the above formula (6), as the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ^2α , the carbon number 3 to 20 represented by R ⁸ in the above formula (1) can be preferably used The monovalent alicyclic hydrocarbon group.

When the high fluorine content resin contains the structural unit having an alicyclic structure, the content ratio of the structural unit having an alicyclic structure is preferably 10 mol % relative to all the structural units constituting the high fluorine content resin Above, more preferably 20 mol % or more, still more preferably 30 mol % or more. In addition, it is preferably 70 mol % or less, more preferably 60 mol % or less, and still more preferably 50 mol % or less.

As a lower limit of Mw of a high fluorine content resin, 1,000 is preferable, 2,000 is more preferable, 3,000 is still more preferable, and 5,000 is especially preferable. The upper limit of the Mw is preferably 50,000, more preferably 30,000, still more preferably 20,000, and particularly preferably 15,000.

The lower limit of Mw/Mn of the high fluorine content resin is usually 1, and more preferably 1.1. The upper limit of the Mw/Mn is usually 5, preferably 3, more preferably 2, still more preferably 1.9.

The content of the high fluorine content resin is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 1 part by mass or more, and particularly preferably 1.5 part by mass or more, relative to 100 parts by mass of the base resin. Moreover, 15 mass parts or less are preferable, 12 mass parts or less are more preferable, 10 mass parts or less are still more preferable, and 8 mass parts or less are especially preferable.

By setting the content of the high-fluorine-containing resin to the above-mentioned range, the high-fluorine-containing resin can be more effectively biased to exist in the surface layer of the resist film, and as a result, the resistance of the resist film at the time of immersion exposure can be further improved. Water repellency of the surface. The radiation-sensitive resin composition may contain one kind or two or more kinds of high fluorine content resins.

(Synthesis method of resin with high fluorine content) The high fluorine content resin can be synthesized by the same method as the synthesis method of the base resin.

(radiosensitive acid generator) The radiation-sensitive resin composition of the present embodiment preferably further contains a radiation-sensitive acid generator that generates a pKa by irradiation (exposure) with radiation, rather than a radiation-sensitive acid generator generated from the onium salt compound. Acids that are less acidic, ie, relatively strong acids. When the resin contains the structural unit (I) having an acid dissociable group, the acid generated from the radiation-sensitive acid generator by exposure to light can dissociate the acid dissociable group contained in the structural unit (I), Thereby producing a carboxyl group and the like. This function is different from the function of the onium salt compound, which does not substantially dissociate the acid contained in the structural unit (I) and the like of the resin under the pattern forming conditions using the radiation-sensitive resin composition. In the unexposed part, the diffusion of the acid generated from the radiation-sensitive acid generator is suppressed. The difference in the functions of the onium salt compound and the radiation-sensitive acid generator is given by the energy required for dissociation of the acid-dissociable group possessed by the structural unit (I) of the resin, etc., and the formation of a pattern using the radiation-sensitive resin composition. the thermal energy conditions, etc. The radiation-sensitive acid generator in the radiation-sensitive resin composition may be contained in a form in which it exists alone as a compound (free from a polymer), or a form in which it is incorporated as a part of a polymer, or Although these two forms may be sufficient, the form which exists individually as a compound is preferable.

When the radiation-sensitive resin composition contains the radiation-sensitive acid generator, the polarity of the resin in the exposed part increases, and when the resin in the exposed part is developed in an alkaline aqueous solution, it becomes soluble in the developing solution. , in the case of organic solvent development, it becomes poorly soluble with respect to the developer.

Examples of the acid generator include onium salt compounds (excluding the above-mentioned onium salt compound (1)), sulfonimide compounds, halogen-containing compounds, diazoketone compounds, and the like. As an onium salt compound, a pernium salt, a tetrahydrothiophenium salt, an iodonium salt, a phosphonium salt, a diazonium salt, a pyridinium salt, etc. are mentioned, for example. Among these, pericynium salts and iodonium salts are preferred.

As an acid generated by exposure, a sulfonic acid is generated by exposure. Examples of such an acid include compounds in which one or more fluorine atoms or fluorinated hydrocarbon groups are substituted with carbon atoms adjacent to the sulfo group. Among them, as the radiation-sensitive acid generator, those having a cyclic structure are particularly preferred.

These radiation-sensitive acid generators may be used alone or in combination of two or more. With respect to 100 parts by mass of the base resin, the content of the radiation-sensitive acid generator (when a plurality of types of radiation-sensitive acid generators are used in combination, the sum of these) is preferably 0.1 part by mass or more, more preferably 1 part by mass part or more, more preferably 5 parts by mass or more. Moreover, 40 mass parts or less are preferable with respect to 100 mass parts of said resins, 35 mass parts or less are more preferable, 30 mass parts or less are further more preferable, and 20 mass parts or less are especially preferable. Thereby, excellent sensitivity, LWR performance, and CDU performance can be exhibited when forming a resist pattern.

(solvent) The radiation-sensitive resin composition of the present embodiment contains a solvent. The solvent is not particularly limited as long as it can dissolve or disperse at least the compound (1), the resin, and, if necessary, a radiation-sensitive acid generator and the like.

Examples of the solvent include alcohol-based solvents, ether-based solvents, ketone-based solvents, amide-based solvents, ester-based solvents, hydrocarbon-based solvents, and the like.

Examples of alcohol-based solvents include: Isopropanol, 4-methyl-2-pentanol, 3-methoxybutanol, n-hexanol, 2-ethylhexanol, furfuryl alcohol, cyclohexanol, 3,3,5-trimethylcyclohexanol , Diacetone alcohol and other mono-alcohol solvents with carbon number of 1 to 18; Ethylene glycol, 1,2-propylene glycol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, etc. carbon number 2 ~18 polyol-based solvents; A polyhydric alcohol partial ether type solvent etc. which etherify a part of the hydroxyl group which the said polyhydric alcohol type solvent has.

Examples of ether-based solvents include: Dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether; Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran; Diphenyl ether, anisole (methyl phenyl ether) and other ether solvents containing aromatic rings; A polyol ether-based solvent or the like obtained by etherifying a hydroxyl group contained in the polyol-based solvent.

Examples of the ketone-based solvent include chain ketone-based solvents such as acetone, methyl ethyl ketone, and methyl-isobutyl ketone; Cyclic ketone solvents such as cyclopentanone, cyclohexanone, methyl cyclohexanone; 2,4-pentanedione, acetone acetone, acetophenone, etc.

Examples of the amide-based solvent include cyclic amide-based solvents such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone; N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide Chain amide solvents such as amide and N-methylpropionamide, etc.

Examples of ester-based solvents include: Monocarboxylate solvents such as n-butyl acetate and ethyl lactate; Diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate and other polyhydric alcohol partial ether acetate solvents; Lactone solvents such as γ-butyrolactone and valerolactone; Carbonate-based solvents such as diethyl carbonate, ethylene carbonate, and propyl carbonate; Polycarboxylic acid diester-based solvents such as propylene glycol diacetate, methoxytriethylene glycol acetate, diethyl oxalate, ethyl acetate, ethyl lactate, and diethyl phthalate.

Examples of hydrocarbon-based solvents include: Aliphatic hydrocarbon solvents such as n-hexane, cyclohexane and methylcyclohexane; Aromatic hydrocarbon-based solvents such as benzene, toluene, diisopropylbenzene, n-pentylnaphthalene, and the like.

Among these, ester-based solvents and ketone-based solvents are preferred, polyol partial ether acetate-based solvents, cyclic ketone-based solvents, and lactone-based solvents are more preferred, and propylene glycol monomethyl ether acetate, Cyclohexanone, gamma-butyrolactone. The radiation-sensitive resin composition may contain one or two or more kinds of solvents.

(any other ingredients) The radiation-sensitive resin composition may contain other arbitrary components in addition to the above-mentioned components. Examples of the other optional components include a crosslinking agent, a biasing accelerator, a surfactant, an alicyclic skeleton-containing compound, a sensitizer, and the like. These other optional components may be used alone or in combination of two or more.

(crosslinking agent) The crosslinking agent is a compound having two or more functional groups, and in the baking step after the general exposure step, a crosslinking reaction is induced in the resin component by an acid catalyst reaction, and the molecular weight of the resin component is increased. By increasing, the solubility of the pattern exposure portion with respect to the developing solution is decreased. As said functional group, a (meth)acryloyl group, a hydroxymethyl group, an alkoxymethyl group, an epoxy group, a vinyl ether group, etc. are mentioned, for example.

(biased towards existential accelerators) The localization accelerator has the effect of making the high fluorine content resin more efficiently localized on the surface of the resist film. By making the radiation-sensitive resin composition contain the biased existence accelerator, the addition amount of the high-fluorine-content resin can be reduced compared with the conventional method. Therefore, while maintaining the lithography performance of the radiation-sensitive resin composition, the elution of components from the resist film to the liquid immersion medium can be further suppressed, or the liquid immersion exposure can be performed at a higher speed by high-speed scanning. As a result, It is possible to improve the hydrophobicity of the surface of the resist film which suppresses defects derived from liquid immersion such as watermark defects. As a thing which can be used as such a biasing accelerator, for example, the relative dielectric constant is 30 or more and 200 or less, and a low molecular weight compound whose boiling point is 100 degreeC or more at 1 atmospheric pressure is mentioned. As such a compound, a lactone compound, a carbonate compound, a nitrile compound, a polyhydric alcohol etc. are mentioned specifically,.

As said lactone compound, gamma-butyrolactone, valerolactone, mevalonic lactone, norbornane lactone etc. are mentioned, for example.

As said carbonate compound, propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, etc. are mentioned, for example.

As said nitrile compound, succinonitrile etc. are mentioned, for example.

As said polyhydric alcohol, glycerol etc. are mentioned, for example.

With respect to 100 parts by mass of the total amount of resin in the radiation-sensitive resin composition, the content of the biasing accelerator is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and still more preferably 20 parts by mass or more, Particularly preferred is 25 parts by mass or more. Moreover, 300 mass parts or less are preferable, 200 mass parts or less are more preferable, 100 mass parts or less are still more preferable, and 80 mass parts or less are especially preferable. The radiation-sensitive resin composition may also contain one or two or more kinds of biased existence accelerators.

(surfactant) The surfactant has the effect of improving coatability, striation, developability, and the like. As the surfactant, for example, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyoxyethylene Nonionic surfactants such as ethylene glycol dilaurate and polyethylene glycol distearate; commercially available products include KP341 (manufactured by Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75. Polyflow No.95 (above manufactured by Gongrongsha Chemical), Eftop EF301, Eftop EF303, Eftop EF352 (above by Taokai Tohchem Products), Megafac F171, Megafac F173 (above manufactured by DIC), Fluorad FC430, Fluorad FC431 (above manufactured by Sumitomo 3M), Asahi Guard AG710, Surflon S-382, Surflon SC-101, Surflon SC-102, Surflon ) SC-103, Surflon SC-104, Surflon SC-105, Surflon SC-106 (the above are manufactured by Asahi Glass Industries), etc. The content of the surfactant in the radiation-sensitive resin composition is usually 2 parts by mass or less with respect to 100 parts by mass of the resin.

(compounds containing alicyclic skeleton) The compound containing an alicyclic skeleton has the effect of improving dry etching resistance, pattern shape, adhesion to a substrate, and the like.

Examples of compounds containing an alicyclic skeleton include: Adamantane derivatives such as 1-adamantane carboxylic acid, 2-adamantanone, 1-adamantane carboxylic acid tert-butyl ester; Deoxycholate esters such as 3-butyl deoxycholate, 3-butoxycarbonyl deoxycholate, and 2-ethoxyethyl deoxycholate; Lithocholic acid 3-butyl ester, lithocholic acid 3-butoxycarbonyl methyl ester, lithocholic acid 2-ethoxyethyl ester and other lithocholic acid esters; 3-[2-Hydroxy-2,2-bis(trifluoromethyl)ethyl]tetracyclo[4.4.0.1(2,5).1(7,10)]dodecane, 2-hydroxy-9- Methoxycarbonyl-5-oxo-4-oxa-tricyclo[4.2.1.0(3,7)]nonane, etc. The content of the alicyclic skeleton-containing compound in the radiation-sensitive resin composition is usually 5 parts by mass or less with respect to 100 parts by mass of the resin.

(sensitizer) The sensitizer has the effect of increasing the amount of acid generated from the radiation-sensitive acid generator or the like, and has the effect of improving the "apparent sensitivity" of the radiation-sensitive resin composition.

Examples of sensitizers include: carbazoles, acetophenones, benzophenones, naphthalenes, phenols, diacetyl, eosin, rose Bengal, pyrenes, anthracenes, phenothiazine class etc. These sensitizers may be used alone or in combination of two or more. The content of the sensitizer in the radiation-sensitive resin composition is usually 2 parts by mass or less with respect to 100 parts by mass of the resin.

<Preparation method of radiation-sensitive resin composition> The radiation-sensitive resin composition can be prepared, for example, by mixing the compound (A), a resin, a radiation-sensitive acid generator, optionally a high fluorine content resin, etc., and a solvent in a predetermined ratio. The radiation-sensitive resin composition is preferably filtered, for example, with a filter having a pore size of about 0.05 μm after mixing. The solid content concentration of the radiation-sensitive resin composition is usually 0.1 to 50 mass %, preferably 0.5 to 30 mass %, and more preferably 1 to 2 mass %.

<Pattern formation method> A pattern forming method according to an embodiment of the present invention includes: Step (1) (hereinafter, also referred to as "resist film forming step"), directly or indirectly coating the radiation-sensitive resin composition on the substrate to form a resist film; step (2) (hereinafter, also referred to as "exposure step"), exposing the resist film; and In step (3) (hereinafter, also referred to as "development step"), the exposed resist film is developed.

According to the resist pattern forming method, since the radiation-sensitive resin composition excellent in sensitivity, CDU performance, and LWR performance in the exposure step is used, a high-quality resist pattern can be formed. Hereinafter, each step will be described.

[Resist film formation step] In this step (the step (1)), a resist film is formed using the radiation-sensitive resin composition. As a substrate on which the resist film is formed, for example, conventionally known ones such as silicon wafers, silicon dioxide, and aluminum-coated wafers can be mentioned. In addition, an organic or inorganic antireflection film disclosed in, for example, Japanese Patent Laid-Open No. 6-12452, Japanese Patent Laid-Open No. 59-93448, etc. may be formed on the substrate. As a coating method, spin coating (spin coating), casting coating, roll coating, etc. are mentioned, for example. After coating, prebake (PB) may be performed as necessary to volatilize the solvent in the coating film. The PB temperature is usually 60°C to 140°C, preferably 80°C to 120°C. The PB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds. The thickness of the resist film to be formed is preferably 10 nm to 1,000 nm, and more preferably 10 nm to 500 nm.

In the case of liquid immersion exposure, regardless of the presence or absence of water-repellent polymer additives such as the high fluorine content resin in the radiation-sensitive resin composition, in order to avoid direct contact between the liquid immersion liquid and the resist film For the purpose of immersion, a liquid immersion protective film which is insoluble to the liquid immersion liquid may be provided on the formed resist film. As the protective film for liquid immersion, a solvent peeling type protective film that is peeled off with a solvent before the development step (for example, refer to Japanese Patent Laid-Open No. 2006-227632), and a developer peeling type that is peeled off simultaneously with the development of the developing step can also be used Any of the protective films (for example, refer to WO2005-069076 A and WO2006-035790). Among them, from the viewpoint of yield, it is preferable to use a developing solution peeling-type liquid immersion protective film.

In addition, when performing the exposure step as the next step with radiation having a wavelength of 50 nm or less, it is preferable to use a resin having the structural unit (I) and the structural unit (IV) as a base in the composition resin.

[Exposure step] In this step (the step (2)), the resist film formed in the step (1), that is, the resist film forming step, is irradiated with radiation through a photomask (via a liquid immersion medium such as water as appropriate) to expose. Examples of radiation used for exposure include electromagnetic waves such as visible rays, ultraviolet rays, extreme ultraviolet rays, extreme ultraviolet rays (EUV), X rays, and γ rays, and charged particle beams such as electron beams and α rays, depending on the line width of the target pattern. . Among them, far-ultraviolet rays, electron beams, EUV are preferred, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), electron beams, EUV are more preferred, and further preferred are positioned as Electron beam and EUV with wavelengths below 50 nm for next-generation exposure technology.

When exposure is performed by liquid immersion exposure, as a liquid immersion liquid to be used, water, a fluorine-type inert liquid, etc. are mentioned, for example. The immersion liquid is preferably a liquid that is transparent to the exposure wavelength and has a temperature coefficient of refractive index as small as possible to minimize the distortion of the optical image projected on the film, especially when the exposure light source is an ArF excimer laser. In the case of irradiated light (wavelength of 193 nm), it is preferable to use water from the viewpoints of easiness of acquisition, easiness of handling, and the like. In the case of using water, an additive which reduces the surface tension of water and increases the interfacial active force may be added at a slight ratio. The additive preferably does not dissolve the resist film on the wafer and has a negligible effect on the optical coating on the lower surface of the lens. As the water to be used, distilled water is preferred.

Preferably, a post exposure bake (PEB) is performed after the exposure, and in the exposed portion of the resist film, the acid generated by the self-inductive radiation acid generator by exposure is used to promote the resin Dissociation of acid dissociable groups, etc. Due to the PEB, the difference in solubility with respect to the developer occurs between the exposed portion and the unexposed portion. The PEB temperature is usually 50°C to 180°C, preferably 80°C to 130°C. The PEB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

[Development step] In this step (the step (3)), the resist film exposed in the step (2), that is, the exposure step, is developed. Thereby, a predetermined resist pattern can be formed. Generally, it wash|cleans with the rinse liquid, such as water or alcohol, after image development, and it is dried.

As the developing solution used for the development, in the case of alkali development, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia water, ethylamine, n-propyl amine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethyl ammonium hydroxide (TMAH), Bases such as pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, 1,5-diazabicyclo-[4.3.0]-5-nonene Alkaline aqueous solution of at least one kind of compound, etc. Among these developing solutions, a TMAH aqueous solution is preferable, and a 2.38 mass % TMAH aqueous solution is more preferable.

In addition, in the case of developing with an organic solvent, organic solvents such as hydrocarbon-based solvents, ether-based solvents, ester-based solvents, ketone-based solvents, and alcohol-based solvents, or solvents containing organic solvents are exemplified. As the organic solvent, for example, one or two or more of the solvents listed as the solvent of the radiation-sensitive resin composition may be mentioned. Among these, ether-based solvents, ester-based solvents, and ketone-based solvents are preferred. The ether-based solvent is preferably a glycol ether-based solvent, and more preferably ethylene glycol monomethyl ether and propylene glycol monomethyl ether. As the ester-based solvent, an acetate-based solvent is preferable, and n-butyl acetate and amyl acetate are more preferable. The ketone-based solvent is preferably a chain ketone, more preferably 2-heptanone. The content of the organic solvent in the developer is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and particularly preferably 99% by mass or more. As a component other than the organic solvent in a developer, water, a silicone oil, etc. are mentioned, for example.

As described above, the developer may be either an alkaline developer or an organic solvent developer, but it is preferable that the developer contains an organic solvent, and the obtained pattern is a negative pattern.

Examples of the developing method include: a method of immersing a substrate in a tank filled with a developing solution for a fixed period of time (dipping method); a method of developing by depositing a developing solution on the surface of the substrate by utilizing surface tension and standing still for a fixed period of time (overlay method) The puddle method); the method of spraying the developer on the surface of the substrate (spray method); the method of continuously applying the developer to the substrate rotating at a fixed speed while scanning the developer coating nozzle at a fixed speed (dynamic distribution method) etc.

（所述式（1）中， R ^f為氟原子或碳數1～10的一價氟化烴基。 R ¹～R ³分別獨立地為氫原子或碳數1～20的一價烴基，或者表示R ¹～R ³中的兩個相互結合並與該些所鍵結的碳原子一起構成的碳數3～20的環狀結構。 n為1～4的整數。於n為2以上的情況下，多個R ²及R ³彼此相同或不同， Z ⁺為一價的感放射線性鎓陽離子）。 <Onium salt compound (1)> The onium salt compound of still another embodiment of the present invention is represented by the following formula (1). [Chemical 26]

(In the above formula (1), R ^f is a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms. R ¹ to R ³ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, or Represents a cyclic structure having 3 to 20 carbon atoms in which two of R ¹ to R ³ are bonded to each other and together with these bonded carbon atoms. n is an integer of 1 to 4. When n is 2 or more In the following, a plurality of R ² and R ³ are the same or different from each other, and Z ⁺ is a monovalent radioactive onium cation).

As the onium salt compound represented by the formula (1) of the present embodiment, the onium salt compound (1) contained in the radiation-sensitive resin composition can be preferably used. [Example]

Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples. The measurement methods of various physical property values are shown below.

[Weight Average Molecular Weight (Mw) and Number Average Molecular Weight (Mn)] The Mw and Mn of the polymer were measured under the above-mentioned conditions. In addition, the degree of dispersion (Mw/Mn) was calculated from the measurement results of Mw and Mn.

[ ¹³ C-Nuclear Magnetic Resonance (NMR) Analysis] The ¹³ C-NMR analysis of the resin was carried out using a nuclear magnetic resonance apparatus (“JNM-Delta400” from Japan Electron Co., Ltd.).

<Synthesis of resin and resin with high fluorine content> The monomers used for the synthesis of each resin and high fluorine content resin in each Example and each Comparative Example are shown below. In addition, in the following synthesis examples, unless otherwise specified, the parts by mass refer to the value when the total mass of the monomers used is 100 parts by mass, and the mole % refers to the amount of the monomers used. The total number of moles of the body is set to the value when 100 mole%.

[Chemical 27]

[Synthesis Example 1] (Synthesis of Resin (A-1)) Monomer (M-1), Monomer (M-2), and Monomer (M-10) were molar ratio of 40/15 2-butanone (200 parts by mass) was dissolved in 2-butanone (200 parts by mass) so as to be /45 (mol %), and azobisisobutyronitrile (AIBN) was added as a starting agent (100 mol per total of the monomers used). % instead of 3 mol%) to prepare a single volume solution. 2-Butanone (100 parts by mass) was placed in the reaction container, and after 30 minutes of nitrogen flushing, the inside of the reaction container was set to 80° C., and the monomer solution was added dropwise over 3 hours while stirring. The start of dropwise addition was set as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours. After the completion of the polymerization reaction, the polymerization solution was cooled to 30°C or lower by water-cooling. The cooled polymerization solution was put into methanol (2,000 parts by mass), and the precipitated white powder was separated by filtration. After the white powder separated by filtration was washed twice with methanol, it was separated by filtration, and dried at 50° C. for 24 hours to obtain a white powdery polymer (A-1) (yield: 80%). Resin (A-1) had Mw of 8,700 and Mw/Mn of 1.49. In addition, as a result of ¹³ C-NMR analysis, the content ratios of the respective structural units derived from (M-1), (M-2) and (M-10) were 39.9 mol %, 14.3 mol % and 45.8 mol %, respectively. Ear%.

[Synthesis Example 2 to Synthesis Example 11] (Synthesis of resin (A-2) to resin (A-11)) Resin (A-2) to resin (A-11) were synthesized in the same manner as in Synthesis Example 1, except that the monomers of the types and compounding ratios shown in the following Table 1 were used. The content ratio (mol %), yield (%), and physical property values (Mw and Mw/Mn) of each structural unit of the obtained resin are collectively shown in Table 1 below. In addition, "-" in the following Table 1 means that the corresponding monomer is not used (the same applies to the following tables).

[Table 1] [A] Resin Monomers that provide structural units (I) Monomers that provide structural unit (II) Monomers that provide structural unit (III) Mw Mw/Mn type Allocation ratio (mol%) Structural unit content (mol%) type Allocation ratio (mol%) Structural unit content (mol%) type Allocation ratio (mol%) Structural unit content (mol%) Synthesis Example 1 A-1 M-1 40 39.9 M-10 45 45.8 - - - 8700 1.49 M-2 15 14.3 Synthesis Example 2 A-2 M-1 30 31.4 M-15 60 60.6 - - - 9000 1.44 M-2 10 8.0 Synthesis Example 3 A-3 M-1 30 31.9 M-11 60 61.7 - - - 8900 1.39 M-3 10 6.4 Synthesis Example 4 A-4 M-1 35 32.3 M-13 45 49.6 - - - 8500 1.59 M-3 20 18.1 Synthesis Example 5 A-5 M-1 40 41.1 M-9 45 45.7 - - - 8700 1.44 M-4 15 13.2 Synthesis Example 6 A-6 M-1 40 41.6 M-8 45 46.1 - - - 7700 1.51 M-4 15 12.3 Synthesis Example 7 A-7 M-1 40 42.4 M-7 45 39.5 M-12 15 18.1 7800 1.59 Synthesis Example 8 A-8 M-1 40 41.1 M-6 40 35.7 M-16 20 23.2 8100 1.56 Synthesis Example 9 A-9 M-1 50 51.0 M-5 50 49.0 - - - 7800 1.55 Synthesis Example 10 A-10 M-1 40 44.4 M-13 60 55.6 - - - 7900 1.59 Synthesis Example 11 A-11 M-1 40 42.8 M-6 60 57.2 - - - 8000 1.43

[Synthesis Example 12] (Synthesis of Resin (A-12)) Monomer (M-1) and Monomer (M-18) were dissolved in a molar ratio of 50/50 (mol %). To 1-methoxy-2-propanol (200 parts by mass), AIBN (5 mol %) as a starting agent was added to prepare a single-body solution. 1-Methoxy-2-propanol (100 parts by mass) was placed in the reaction vessel, and after 30 minutes of nitrogen flushing, the inside of the reaction vessel was set to 80°C, and the monomer was added dropwise over 3 hours while stirring. solution. The start of dropwise addition was set as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours. After the completion of the polymerization reaction, the polymerization solution was cooled to 30°C or lower by water-cooling. The cooled polymerization solution was put into hexane (2,000 parts by mass), and the precipitated white powder was separated by filtration. After the white powder separated by filtration was washed twice with hexane, it was separated by filtration and dissolved in 1-methoxy-2-propanol (300 parts by mass). Next, methanol (500 parts by mass), triethylamine (50 parts by mass), and ultrapure water (10 parts by mass) were added, and a hydrolysis reaction was performed at 70° C. for 6 hours while stirring. After the completion of the reaction, the residual solvent was distilled off, the obtained solid was dissolved in acetone (100 parts by mass), and added dropwise to water (500 parts by mass) to solidify the resin. The obtained solid was separated by filtration, and dried at 50° C. for 13 hours to obtain a white powdery resin (A-12) (yield: 79%). Resin (A-12) had Mw of 5,200 and Mw/Mn of 1.60. In addition, as a result of ¹³ C-NMR analysis, the content ratios of the respective structural units derived from (M-1) and (M-18) were 51.3 mol % and 48.7 mol %, respectively.

[Synthesis Example 13 to Synthesis Example 15] (Synthesis of resin (A-13) to resin (A-15)) Resin (A-13) to resin (A-15) were synthesized in the same manner as in Synthesis Example 12, except that the monomers of the types and compounding ratios shown in the following Table 2 were used. The content ratio (mol %), yield (%), and physical property values (Mw and Mw/Mn) of each structural unit of the obtained resin are collectively shown in Table 2 below.

[Table 2] [A] Resin Monomers that provide structural units (I) Monomers that provide structural unit (III) Monomers that provide building blocks (IV) Mw Mw/Mn type Allocation ratio (mol%) Structural unit content (mol%) type Allocation ratio (mol%) Structural unit content (mol%) type Allocation ratio (mol%) Structural unit content (mol%) Synthesis Example 12 A-12 M-1 50 51.3 - - - M-18 50 48.7 5200 1.60 Synthesis Example 13 A-13 M-3 50 47.7 M-16 20 20.1 M-19 30 32.2 5800 1.51 Synthesis Example 14 A-14 M-2 50 48.1 M-17 20 21.3 M-18 30 30.6 5100 1.59 Synthesis Example 15 A-15 M-1 55 54.3 M-17 15 15.6 M-19 30 30.1 6200 1.53

[Synthesis Example 16] (Synthesis of High Fluorine Content Resin (E-1)) Monomer (M-1) and Monomer (M-20) were prepared in a molar ratio of 20/80 (mol %). The solution was dissolved in 2-butanone (200 parts by mass), and AIBN (4 mol %) was added as a starting agent to prepare a single-body solution. 2-Butanone (100 parts by mass) was placed in the reaction container, and after 30 minutes of nitrogen flushing, the inside of the reaction container was set to 80° C., and the monomer solution was added dropwise over 3 hours while stirring. The start of dropwise addition was set as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours. After the completion of the polymerization reaction, the polymerization solution was cooled to 30°C or lower by water-cooling. After replacing the solvent with acetonitrile (400 parts by mass), hexane (100 parts by mass) was added and stirred, and the acetonitrile layer was recovered, and the operation was repeated three times. By replacing the solvent with propylene glycol monomethyl ether acetate, a solution (yield: 69%) of the high fluorine content resin (E-1) was obtained. The high fluorine content resin (E-1) had Mw of 6,000 and Mw/Mn of 1.62. Furthermore, as a result of ¹³ C-NMR analysis, the content ratios of the respective structural units derived from (M-1) and (M-20) were 19.9 mol % and 80.1 mol %, respectively.

[Synthesis Example 17 to Synthesis Example 20] (Synthesis of high fluorine content resin (E-2) to high fluorine content resin (E-5)) The high fluorine content resin (E-2) to the high fluorine content resin (E-5) were synthesized in the same manner as in Synthesis Example 16, except that the monomers of the types and compounding ratios shown in the following Table 3 were used. The content ratio (mol %), yield (%), and physical property values (Mw and Mw/Mn) of each structural unit of the obtained high-fluorine-content resin are collectively shown in Table 3 below.

[table 3] [E] High fluorine content resin Provide the amount of structural units (V), (VI) monomers Monomers that provide structural units (I) Monomers that provide structural unit (III) Monomers that provide other building blocks Mw Mw/Mn type Allocation ratio (mol%) Structural unit content (mol%) type Allocation ratio (mol%) Structural unit content (mol%) type Allocation ratio (mol%) Structural unit content (mol%) type Allocation ratio (mol%) Structural unit content (mol%) Synthesis Example 16 E-1 M-20 80 80.1 M-1 20 19.9 - - - - - - 6000 1.62 Synthesis Example 17 E-2 M-22 80 81.9 M-1 20 18.1 - - - - - - 7200 1.77 Synthesis Example 18 E-3 M-14 60 62.3 - - - - - - M-21 40 38.7 6300 1.82 Synthesis Example 19 E-4 M-14 70 68.7 - - - M-12 30 31.3 - - - 6500 1.81 Synthesis Example 20 E-5 M-14 70 72.3 - - - M-17 30 27.7 - - - 6200 1.78

<Synthesis of Acid Diffusion Controlling Agent C> [Example 1] (Synthesis of Compound (C-1)) Compound (C-1) was synthesized according to the following synthesis scheme.

[Chemical 28]

20.0 mmol of ethyl pentafluoropropionyl acetate, 24.0 mmol of sodium borohydride, and toluene were added to the reaction vessel to prepare a 0.5 M solution, and the reaction was carried out at room temperature for 3 hours. Then, after adding a saturated aqueous ammonium chloride solution to stop the reaction, ethyl acetate was added for extraction, and the organic layer was separated. The obtained organic layer was washed with a saturated aqueous sodium chloride solution and then with water. After drying with sodium sulfate, the solvent was distilled off, and the β-hydroxyester body was obtained in good yield by purification by column chromatography.

To 20.0 mmol of the β-hydroxyester body, a mixture of acetonitrile: water (1:1 (mass ratio)) was added to make a 1M solution, then 24.0 mmol of lithium hydroxide was added, and the reaction was carried out at room temperature for 3 hours to obtain a carboxylic acid Lithium salt.

To 20.0 mmol of the lithium carboxylate salt, 20.0 mmol of triphenyl perionium chloride was added, and a mixed solution of water:dichloromethane (1:1 (mass ratio)) was added to prepare a 0.5 M solution. After vigorous stirring at room temperature for 3 hours, dichloromethane was added for extraction, and the organic layer was separated. After drying the obtained organic layer with sodium sulfate, the solvent was distilled off, and the compound (C-1) represented by the said formula (C-1) was obtained.

[Example 2 to Example 10] (Synthesis of Compound (C-2) to Compound (C-10)) The radiation-sensitive acid diffusion control agents represented by the following formulae (C-2) to (C-10) were synthesized in the same manner as in the synthesis example, except that the raw materials and precursors were appropriately changed.

[Chemical 29]

[Example 11] (Synthesis of Compound (C-11)) Compound (C-11) was synthesized according to the following synthetic scheme.

[Chemical 30]

20.0 mmol of ethyl pentafluoropropionyl acetate and THF were added to the reaction vessel to prepare a 0.5 M solution, and then cooled to -20°C, and a THF solution of 20.0 mmol of methylmagnesium bromide was added dropwise, and the reaction was carried out for 3 hours. Then, after adding a saturated aqueous ammonium chloride solution to stop the reaction, ethyl acetate was added for extraction, and the organic layer was separated. The obtained organic layer was washed with a saturated aqueous sodium chloride solution and then with water. After drying with sodium sulfate, the solvent was distilled off, and the β-hydroxyester body was obtained in good yield by purification by column chromatography.

To 20.0 mmol of the β-hydroxyester body, a mixture of acetonitrile: water (1:1 (mass ratio)) was added to make a 1M solution, then 20.0 mmol of lithium hydroxide was added, and the reaction was carried out at room temperature for 3 hours to obtain a carboxylic acid Lithium salt.

To 20.0 mmol of the lithium carboxylate salt, 20.0 mmol of triphenyl perionium chloride was added, and a mixed solution of water:dichloromethane (1:1 (mass ratio)) was added to prepare a 0.5 M solution. After vigorous stirring at room temperature for 3 hours, dichloromethane was added for extraction, and the organic layer was separated. After drying the obtained organic layer with sodium sulfate, the solvent was distilled off, and the compound (C-11) represented by the said formula (C-11) was obtained.

[Example 12 to Example 13] (Synthesis of Compound (C-12) to Compound (C-13)) The radiation-sensitive acid diffusion control agents represented by the following formulae (C-12) to (C-13) were synthesized in the same manner as in the synthesis example, except that the raw materials and precursors were appropriately changed.

[Chemical 31]

[Radiation-sensitive acid diffusion control agents other than compounds (C-1) to (C-13)] cc-1 to cc-9: compounds represented by the following formulas (cc-1) to (cc-9) (hereinafter, compounds represented by formulas (cc-1) to (cc-9) may be referred to as They are respectively described as "compound (cc-1)" to "compound (cc-9)").

[Chemical 32]

[[B]Radiation-sensitive acid generator] B-1 to B-6: compounds represented by the following formulae (B-1) to (B-6) (hereinafter, the compounds represented by the formulas (B-1) to (B-6) may be referred to as They are respectively described as "Compound (B-1)" to "Compound (B-6)").

[Chemical 33]

[[D]solvent] D-1: Propylene glycol monomethyl ether acetate D-2: cyclohexanone D-3: γ-Butyrolactone D-4: Ethyl lactate

[Preparation of Negative Radiation Sensitive Resin Composition for ArF Exposure] [Example 14] 100 parts by mass of (A-1) as a resin, 15.0 parts by mass of (B-1) as a radiation-sensitive acid generator, 3.0 parts by mass of (C-1) as an acid diffusion control agent, and a resin with a high fluorine content were mixed (E-1) 5.0 parts by mass (solid content), and 3,230 mass of a mixed solvent of (D-1)/(D-2)/(D-3)=69/30/1 (mass ratio) as a solvent Parts were filtered through a membrane filter with a pore size of 0.2 μm to prepare a radiation-sensitive resin composition (J-14).

[Example 15 to Example 54 and Comparative Example 1 to Comparative Example 9] A radiation-sensitive resin composition (J-15) to a radiation-sensitive resin composition (J-54) and a radiation-sensitive resin composition (J-54) and a radiation-sensitive resin composition (J-54) and a radiation-sensitive resin composition were prepared in the same manner as in Example 14, except that each component of the type and content shown in the following Table 4 was used. Radiation resin composition (CJ-1) to radiation sensitive resin composition (CJ-9).

[Table 4] Radiation sensitive resin composition [A] Resin [B] Radiosensitive acid generator [C] Acid diffusion control agent [E] High fluorine content resin [D] Organic solvent type Content (mass parts) type Content (mass parts) type Content (mass parts) type Content (mass parts) type Content (mass parts) Example 14 J-14 A-1 100 B-1 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 15 J-15 A-1 100 B-1 15.0 C-2 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 16 J-16 A-1 100 B-1 15.0 C-3 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 17 J-17 A-1 100 B-1 15.0 C-4 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 18 J-18 A-1 100 B-1 15.0 C-5 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 19 J-19 A-1 100 B-1 15.0 C-6 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 20 J-20 A-1 100 B-1 15.0 C-7 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 21 J-21 A-1 100 B-1 15.0 C-8 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 22 J-22 A-1 100 B-1 15.0 C-9 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 23 J-23 A-1 100 B-1 15.0 C-10 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 24 J-24 A-1 100 B-1 15.0 C-11 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 25 J-25 A-1 100 B-1 15.0 C-12 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 26 J-26 A-1 100 B-1 15.0 C-13 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 27 J-27 A-2 100 B-1 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 28 J-28 A-3 100 B-1 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 29 J-29 A-4 100 B-1 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 30 J-30 A-5 100 B-1 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 31 J-31 A-6 100 B-1 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 32 J-32 A-7 100 B-1 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 33 J-33 A-8 100 B-1 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 34 J-34 A-9 100 B-1 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 35 J-35 A-10 100 B-1 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 36 J-36 A-11 100 B-1 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 37 J-37 A-1 100 B-2 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 38 J-38 A-1 100 B-3 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 39 J-39 A-1 100 B-4 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 40 J-40 A-1 100 B-5 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 41 J-41 A-1 100 B-6 15.0 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 42 J-42 A-1 100 B-1 15.0 C-1 3.0 E-2 5.0 D-1/D-2/D-3 2240/960/30 Example 43 J-43 A-1 100 B-1 15.0 C-1 3.0 E-3 5.0 D-1/D-2/D-3 2240/960/30 Example 44 J-44 A-1 100 B-1 15.0 C-1 3.0 E-4 5.0 D-1/D-2/D-3 2240/960/30 Example 45 J-45 A-1 100 B-1 15.0 C-1 0.3 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 46 J-46 A-1 100 B-1 15.0 C-1 6.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 47 J-47 A-1 100 B-1 15.0 C-1 12.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 48 J-48 A-1 100 B-1 15.0 C-1/cc-l 1.5/1.5 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 49 J-49 A-1 100 B-1 15.0 Cl/cc-2 1.5/1.5 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 50 J-50 A-1 100 B-1 15.0 Cl/cc-3 1.5/1.5 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 51 J-51 A-1 100 B-1 15.0 Cl/cc-4 1.5/1.5 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 52 J-52 A-1 100 B-1/B-2 7.5/7.5 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 53 J-53 A-1 100 B-1/B-5 7.5/7.5 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Example 54 J-54 A-1 100 B-1/B-6 7.5/7.5 C-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Comparative Example 1 CJ-1 A-1 100 B-1 15.0 cc-1 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Comparative Example 2 CJ-2 A-1 100 B-1 15.0 cc-2 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Comparative Example 3 CJ-3 A-1 100 B-1 15.0 cc-3 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Comparative Example 4 CJ-4 A-1 100 B-1 15.0 cc-4 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Comparative Example 5 CJ-5 A-1 100 B-1 15.0 cc-5 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Comparative Example 6 CJ-6 A-1 100 B-1 15.0 cc-6 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Comparative Example 7 CJ-7 A-1 100 B-1 15.0 cc-7 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Comparative Example 8 CJ-8 A-1 100 B-1 15.0 cc-8 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30 Comparative Example 9 CJ-9 A-1 100 B-1 15.0 cc-9 3.0 E-1 5.0 D-1/D-2/D-3 2240/960/30

<Formation of a resist pattern using a negative radiation-sensitive resin composition for ArF exposure> Using a spin coater (“CLEAN TRACK ACT12” from Tokyo Electron Co., Ltd.), a composition for forming a lower layer antireflection film (“ARC66” from Brewer Science Co., Ltd.) was applied on 12 After being deposited on a silicon wafer of 1.5 inches, it was heated at 205°C for 60 seconds to form a lower anti-reflection film with an average thickness of 105 nm. The prepared negative radiation-sensitive resin composition for ArF exposure was coated on the lower antireflection film using the spin coater, and prebaked (PB) at 90° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with an average thickness of 90 nm. Next, an ArF excimer laser liquid immersion exposure device (“TWINSCAN XT-1900i” from ASML) was used under the optical conditions of NA=1.35, Annular (σ=0.8/0.6), separated by 40 nm space, The resist film was exposed to a mask pattern with a pitch of 105 nm. After exposure, a post-exposure bake (PEB) was performed at 90°C for 60 seconds. After that, using n-butyl acetate as an organic solvent developer, the resist film was developed with an organic solvent and dried to form a negative resist pattern (40 nm line and space pattern). In addition, the mask pattern was changed, and the negative resist pattern (40 nm hole, 105 nm pitch) was formed in the same manner as the above-mentioned operation.

＜Evaluation＞ The sensitivity, LWR performance, and CDU performance of the resist pattern formed using the negative radiation-sensitive resin composition for ArF exposure were evaluated according to the following methods. The results are shown in Table 5 below. In addition, for the length measurement of the resist pattern, a scanning electron microscope (“CG-5000” of Hitachi High-Technologies Co., Ltd.) was used.

[Sensitivity] In the formation of the resist pattern using the negative radiation-sensitive resin composition for ArF exposure, the exposure amount for forming a 40 nm line and space pattern was set as the optimum exposure amount, and the optimum exposure amount was The amount is set to sensitivity (mJ/cm ² ). Regarding the sensitivity, the case of 27 mJ/cm ² or less was evaluated as "good", and the case of more than 27 mJ/cm ² was evaluated as "poor".

[LWR performance] The optimum exposure amount determined in the evaluation of the sensitivity was irradiated, and the mask size was adjusted so as to form a 40 nm line and space pattern to form a resist pattern. Using the scanning electron microscope, the formed resist pattern was observed from the upper part of the pattern. A total of 500 line width deviations were measured, and a 3-sigma value was obtained from the distribution of the measured values, and the 3-sigma value was defined as LWR (nm). The smaller the value of LWR, the smaller and better the line roughness is. Regarding the LWR performance, the case of 3.5 nm or less was evaluated as "good", and the case of more than 3.5 nm was evaluated as "poor".

[CDU performance] Using the scanning electron microscope, a total of 1,800 resist patterns with holes of 40 nm and a pitch of 105 nm were measured at arbitrary points from the top of the pattern. Variation in size (3σ) was obtained and set as CDU performance (nm). The smaller the value of CDU, the smaller the deviation of the pore diameter in the long period, and the better. Regarding CDU performance, the case of 4.5 nm or less was evaluated as "good", and the case of more than 4.5 nm was evaluated as "poor".

[table 5] Radiation sensitive resin composition Sensitivity (mJ/cm ² ) LWR (nm) CDU (nm) Example 14 J-14 26 3.2 4.1 Example 15 J-15 26 3.4 4.3 Example 16 J-16 twenty two 2.7 4.3 Example 17 J-17 26 2.6 4.1 Example 18 J-18 25 3.5 3.6 Example 19 J-19 25 2.7 3.7 Example 20 J-20 25 3.4 4.2 Example 21 J-21 twenty three 3.5 4.1 Example 22 J-22 twenty two 3.3 4.0 Example 23 J-23 27 3.0 3.8 Example 24 J-24 twenty one 3.0 4.5 Example 25 J-25 twenty two 3.0 3.9 Example 26 J-26 26 2.9 4.3 Example 27 J-27 26 3.0 4.2 Example 28 J-28 twenty one 2.7 4.3 Example 29 J-29 26 3.3 4.2 Example 30 J-30 twenty two 2.7 4.4 Example 31 J-31 twenty one 3.4 3.6 Example 32 J-32 25 3.3 3.5 Example 33 J-33 twenty two 3.3 3.7 Example 34 J-34 27 3.1 3.9 Example 35 J-35 27 3.3 3.6 Example 36 J-36 twenty four 2.9 4.4 Example 37 J-37 26 2.8 3.5 Example 38 J-38 twenty one 3.0 3.8 Example 39 J-39 twenty three 3.0 3.8 Example 40 J-40 26 3.3 4.5 Example 41 J-41 twenty two 2.7 4.2 Example 42 J-42 twenty one 3.0 3.6 Example 43 J-43 twenty two 3.1 4.1 Example 44 J-44 25 2.8 4.4 Example 45 J-45 twenty three 3.1 4.2 Example 46 J-46 25 3.3 4.4 Example 47 J-47 25 2.7 4.3 Example 48 J-48 twenty two 3.2 3.7 Example 49 J-49 26 3.0 4.3 Example 50 J-50 25 2.5 3.8 Example 51 J-51 twenty two 3.4 4.5 Example 52 J-52 twenty three 3.0 4.5 Example 53 J-53 twenty one 3.3 4.5 Example 54 J-54 twenty four 2.6 4.3 Comparative Example 1 CJ-1 31 4.8 5.0 Comparative Example 2 CJ-2 30 5.0 4.9 Comparative Example 3 CJ-3 31 4.3 5.9 Comparative Example 4 CJ-4 29 3.5 4.8 Comparative Example 5 CJ-5 30 4.6 4.8 Comparative Example 6 CJ-6 33 3.6 5.8 Comparative Example 7 CJ-7 27 4.3 6.0 Comparative Example 8 CJ-8 29 3.8 5.1 Comparative Example 9 CJ-9 29 3.7 5.9

As is clear from the results in Table 5, when the radiation-sensitive resin compositions of Examples are used for ArF exposure, the sensitivity, LWR performance, and CDU performance are good, and compared with the Examples in Comparative Examples , the characteristics are poor. Therefore, when the radiation-sensitive resin composition of the Example is used for ArF exposure, a resist pattern with good LWR performance and CDU performance can be formed with high sensitivity.

[Preparation of positive radiation-sensitive resin composition for extreme ultraviolet (EUV) exposure] [Example 55] 100 parts by mass of (A-12) as a resin, 20.0 parts by mass of (B-1) as a radiation-sensitive acid generator, 4.0 parts by mass of (C-1) as an acid diffusion control agent, and a resin with a high fluorine content were mixed 3.0 parts by mass of (E-5) and 6,110 parts by mass of a mixed solvent of (D-1)/(D-4)=70/30 (mass ratio) as a solvent, filtered with a membrane filter with a pore size of 0.2 μm, Thereby, a radiation-sensitive resin composition (J-55) was prepared.

[Example 56 to Example 65 and Comparative Example 10 to Comparative Example 13] A radiation-sensitive resin composition (J-56) to a radiation-sensitive resin composition (J-65) and a radiation-sensitive resin composition (J-65) and a radiation-sensitive resin composition (J-65) were prepared in the same manner as in Example 55, except that each component of the type and content shown in the following Table 6 was used. Radiation resin composition (CJ-10) to radiation sensitive resin composition (CJ-13).

[Table 6] Radiation sensitive resin composition [A] Resin [B] Radiosensitive acid generator [C] Acid diffusion control agent [E] High fluorine content resin [D] Organic solvent type Content (mass parts) type Content (mass parts) type Content (mass parts) type Content (mass parts) type Content (mass parts) Example 55 J-55 A-12 100 B-1 20.0 C-1 4.0 E-5 3.0 D-1/D-4 4280/1830 Example 56 J-56 A-12 100 B-1 20.0 C-4 4.0 E-5 3.0 D-1/D-4 4280/1830 Example 57 J-57 A-12 100 B-1 20.0 C-7 4.0 E-5 3.0 D-1/D-4 4280/1830 Example 58 J-58 A-12 100 B-1 20.0 C-9 4.0 E-5 3.0 D-1/D-4 4280/1830 Example 59 J-59 A-12 100 B-1 20.0 C-11 4.0 E-5 3.0 D-1/D-4 4280/1830 Example 60 J-60 A-13 100 B-1 20.0 C-1 4.0 E-5 3.0 D-1/D-4 4280/1830 Example 61 J-61 A-14 100 B-1 20.0 C-1 4.0 E-5 3.0 D-1/D-4 4280/1830 Example 62 J-62 A-15 100 B-1 20.0 C-1 4.0 E-5 3.0 D-1/D-4 4280/1830 Example 63 J-63 A-12 100 B-2 20.0 C-1 4.0 E-5 3.0 D-1/D-4 4280/1830 Example 64 J-64 A-12 100 B-5 20.0 C-1 4.0 E-5 3.0 D-1/D-4 4280/1830 Example 65 J-65 A-12 100 B-6 20.0 C-1 4.0 E-5 3.0 D-1/D-4 4280/1830 Comparative Example 10 CJ-10 A-12 100 B-1 20.0 cc-1 4.0 E-5 3.0 D-1/D-4 4280/1830 Comparative Example 11 CJ-11 A-12 100 B-1 20.0 cc-5 4.0 E-5 3.0 D-1/D-4 4280/1830 Comparative Example 12 CJ-12 A-12 100 B-1 20.0 cc-6 4.0 E-5 3.0 D-1/D-4 4280/1830 Comparative Example 13 CJ-13 A-12 100 B-1 20.0 cc-7 4.0 E-5 3.0 D-1/D-4 4280/1830

<Formation of resist pattern using positive radiation-sensitive resin composition for EUV exposure> Using a spin coater (“CLEAN TRACK ACT12” from Tokyo Electron Co., Ltd.), a composition for forming a lower layer antireflection film (“ARC66” from Brewer Science Co., Ltd.) was applied on 12 After being deposited on a silicon wafer of 1.5 inches, it was heated at 205°C for 60 seconds to form a lower anti-reflection film with an average thickness of 105 nm. The prepared positive-type radiation-sensitive resin composition for EUV exposure was coated on the lower antireflection film using the spin coater, and PB was performed at 130° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with an average thickness of 55 nm. Next, using an EUV exposure apparatus (“NXE3300” from ASML), the resist film was exposed to NA=0.33, illumination condition: Conventional s=0.89, mask: imecDEFECT32FFR02 . After exposure, PEB was performed at 120°C for 60 seconds. Then, using 2.38 mass % TMAH aqueous solution as an alkaline developer, the resist film was subjected to alkaline development, washed with water after development, and further dried to form a positive-type resist pattern ( 32 nm line and space pattern).

＜Evaluation＞ With respect to the resist pattern formed using the positive-type radiation-sensitive resin composition for EUV exposure, sensitivity and LWR performance were evaluated according to the following methods. The results are shown in Table 7 below. In addition, for the length measurement of the resist pattern, a scanning electron microscope (“CG-5000” of Hitachi High-Technologies Co., Ltd.) was used.

[Sensitivity] In the formation of the resist pattern using the positive-type radiation-sensitive resin composition for EUV exposure, the exposure amount for forming a 32 nm line and space pattern was set as the optimum exposure amount, and the optimum exposure amount was The amount is set to sensitivity (mJ/cm ² ). Regarding the sensitivity, the case of 30 mJ/cm ² or less was evaluated as "good", and the case of more than 30 mJ/cm ² was evaluated as "poor".

[LWR performance] The optimum exposure amount determined in the evaluation of the sensitivity was irradiated, and the mask size was adjusted so as to form a 32 nm line-and-space pattern to form a resist pattern. Using the scanning electron microscope, the formed resist pattern was observed from the upper part of the pattern. A total of 500 line width deviations were measured, and a 3-sigma value was obtained from the distribution of the measured values, and the 3-sigma value was defined as LWR (nm). The smaller the value of LWR, the smaller and better the line wobble is. Regarding the LWR performance, the case of 3.8 nm or less was evaluated as "good", and the case of more than 3.8 nm was evaluated as "poor".

[Table 7] Radiation sensitive resin composition Sensitivity (mJ/cm ² ) LWR (nm) Example 55 J-55 30 3.5 Example 56 J-56 29 3.0 Example 57 J-57 twenty four 3.2 Example 58 J-58 25 3.5 Example 59 J-59 twenty four 3.7 Example 60 J-60 26 3.6 Example 61 J-61 25 3.6 Example 62 J-62 30 3.0 Example 63 J-63 28 3.3 Example 64 J-64 25 3.6 Example 65 J-65 26 3.4 Comparative Example 10 CJ-10 35 4.1 Comparative Example 11 CJ-11 35 4.0 Comparative Example 12 CJ-12 32 4.5 Comparative Example 13 CJ-13 32 4.4

As is clear from the results in Table 7, when the radiation-sensitive resin compositions of the examples are used for EUV exposure, the sensitivity and LWR performance are good. On the other hand, in the comparative examples, compared with the examples, the respective properties Difference.

[Preparation of positive radiation-sensitive resin composition for ArF exposure, formation and evaluation of resist pattern using the composition] [Example 66] 100 parts by mass of (A-4) as a resin, 12.0 parts by mass of (B-1) as a radiation-sensitive acid generator, 2.5 parts by mass of (C-1) as an acid diffusion control agent, and a resin with a high fluorine content were mixed (E-2) 3.0 parts by mass (solid content), and 3,230 mass of a mixed solvent of (D-1)/(D-2)/(D-3)=69/30/1 (mass ratio) as a solvent Parts were filtered through a membrane filter with a pore size of 0.2 μm to prepare a radiation-sensitive resin composition (J-66).

Using a spin coater (“CLEAN TRACK ACT12” from Tokyo Electron Co., Ltd.), a composition for forming a lower layer antireflection film (“ARC66” from Brewer Science Co., Ltd.) was applied on 12 After being deposited on a silicon wafer of 1.5 inches, it was heated at 205°C for 60 seconds to form a lower anti-reflection film with an average thickness of 105 nm. Use the spin coater to coat the prepared positive-type radiation-sensitive resin composition (J-53) for ArF exposure on the lower anti-reflection film, and pre-bake at 90°C for 60 seconds (PB). Then, it cooled at 23 degreeC for 30 second, and formed the resist film with an average thickness of 90 nm. Next, an ArF excimer laser liquid immersion exposure device (“TWINSCAN XT-1900i” from ASML) was used under the optical conditions of NA=1.35, Annular (σ=0.8/0.6), separated by 40 nm space, The resist film was exposed to a mask pattern with a pitch of 105 nm. After exposure, a post-exposure bake (PEB) was performed at 90°C for 60 seconds. Then, using 2.38 mass % TMAH aqueous solution as an alkaline developer, the resist film was subjected to alkaline development, washed with water after development, and further dried to form a positive-type resist pattern ( 40 nm line and space pattern).

The resist pattern using the positive radiation-sensitive resin composition for EUV exposure was evaluated in the same manner as the evaluation of the resist pattern using the negative radiation-sensitive resin composition for ArF exposure. As a result, the radiation-sensitive resin composition of Example 66 was good in sensitivity, LWR performance, and CDU performance even when a positive-type resist pattern was formed by ArF exposure.

[Preparation of negative radiation-sensitive resin composition for EUV exposure, formation and evaluation of resist pattern using the composition] [Example 67] 100 parts by mass of (A-12) as a resin, 21.0 parts by mass of (B-1) as a radiation-sensitive acid generator, 5.0 parts by mass of (C-1) as an acid diffusion control agent, and a resin with a high fluorine content were mixed 3.0 parts by mass of (E-5) and 6,110 parts by mass of a mixed solvent of (D-1)/(D-4)=70/30 (mass ratio) as a solvent, filtered with a membrane filter with a pore size of 0.2 μm, Thereby, a radiation-sensitive resin composition (J-67) was prepared.

Using a spin coater (“CLEAN TRACK ACT12” from Tokyo Electron Co., Ltd.), a composition for forming a lower layer antireflection film (“ARC66” from Brewer Science Co., Ltd.) was applied on 12 After being deposited on a silicon wafer of 1.5 inches, it was heated at 205°C for 60 seconds to form a lower anti-reflection film with an average thickness of 105 nm. The prepared negative-type radiation-sensitive resin composition for EUV exposure (J-54) was coated on the lower antireflection film using the spin coater, and PB was performed at 130° C. for 60 seconds. Then, it cooled at 23 degreeC for 30 second, and formed the resist film with an average thickness of 55 nm. Next, using an EUV exposure apparatus (“NXE3300” from ASML), the resist film was exposed to NA=0.33, illumination condition: Conventional s=0.89, mask: imecDEFECT32FFR02 . After exposure, PEB was performed at 120°C for 60 seconds. After that, using n-butyl acetate as an organic solvent developer, the resist film was developed with an organic solvent and dried to form a negative resist pattern (32 nm line and space pattern).

The resist pattern using the negative radiation-sensitive resin composition for EUV exposure was evaluated in the same manner as the evaluation of the resist pattern using the positive radiation-sensitive resin composition for EUV exposure. As a result, the radiation-sensitive resin composition of Example 67 had good sensitivity and LWR performance even when a negative resist pattern was formed by EUV exposure. [Industrial Availability]

According to the radiation-sensitive resin composition, pattern forming method, and onium salt compound described above, a resist pattern having good sensitivity to exposure light and excellent LWR performance and CDU performance can be formed. Therefore, these can be preferably used in the processing and the like of semiconductor elements which are expected to be further miniaturized in the future.

Claims (11)

A radiation-sensitive resin composition comprising: an onium salt compound represented by the following formula (1); a resin comprising a structural unit having an acid dissociable group; and a solvent,

(In the above formula (1), R ^f is a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms, and R ¹ to R ³ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, or Represents a cyclic structure with 3 to 20 carbon atoms in which two of R ¹ to R ³ are bonded to each other and together with these bonded carbon atoms, n is an integer of 1 to 4, and when n is 2 or more In the following, a plurality of R ² and R ³ are the same or different from each other, and Z ⁺ is a monovalent radioactive onium cation). The radiation-sensitive resin composition according to claim 1, wherein in the formula (1), n is 1 or 2. The radiation-sensitive resin composition according to claim 1 or claim 2, wherein in the formula (1), R ^f is a perfluoroalkyl group having 1 to 6 carbon atoms. The radiation-sensitive resin composition according to any one of claim 1 to claim 3, wherein in the formula (1), R ¹ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, R ² and R ³ is each independently a hydrogen atom or a monovalent hydrocarbon group with 1 to 20 carbon atoms, or represents a cyclic structure with 3 to 20 carbon atoms formed by combining R ² and R ³ with the bonded carbon atoms. . The radiation-sensitive resin composition according to any one of Claims 1 to 4, wherein in the formula (1), neither R ^f nor R ¹ to R ³ contains a hydroxyl group. The radiation-sensitive resin composition according to any one of Claims 1 to 5, wherein the radiation-sensitive onium cations in the formula (1) are each independently a pernium cation or an iodonium cation. The radiation-sensitive resin composition according to any one of claim 1 to claim 6, further comprising a radiation-sensitive acid generator, the radiation-sensitive acid generator generating a pKa higher than self-generated by irradiation with radiation The onium salt compound produces a smaller acid. The radiation-sensitive resin composition according to any one of Claims 1 to 7, wherein the structural unit having an acid dissociable group is represented by the following formula (2),

(In the above formula (2), R ⁷ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R ⁸ is a monovalent hydrocarbon group having 1 to 20 carbon atoms, and R ⁹ and R ¹⁰ are each independently a carbon number. A monovalent chain hydrocarbon group of 1 to 10 or a monovalent alicyclic hydrocarbon group of 3 to 20 carbon atoms, or a divalent hydrocarbon group of 3 to 20 carbon atoms in which these groups are combined with each other and together with the bonded carbon atoms. Valence alicyclic group). A pattern forming method comprising: The step of directly or indirectly coating the radiation-sensitive resin composition according to any one of claim 1 to claim 8 on a substrate to form a resist film; the step of exposing the resist film; and The step of developing the exposed resist film with a developing solution. The pattern forming method according to claim 9, wherein the developing is performed with an organic solvent. An onium salt compound represented by the following formula (1),

(In the above formula (1), R ^f is a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 10 carbon atoms, and R ¹ to R ³ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, or Represents a cyclic structure with 3 to 20 carbon atoms in which two of R ¹ to R ³ are bonded to each other and together with these bonded carbon atoms, n is an integer of 1 to 4, and when n is 2 or more In the following, a plurality of R ² and R ³ are the same or different from each other, and Z ⁺ is a monovalent radioactive onium cation).