TW202229220A - Radiation-sensitive composition and method for forming resist pattern - Google Patents

Abstract

Provided is a radiation-sensitive composition which contains a polymer [P] having a radiation-sensitive onium cation structure and an organic anion structure and which satisfies at least one of (i) and (ii). (i) As the polymer [P], contained is a polymer having a radiation-sensitive onium cation structure having two or more substituent groups [beta] of at least one type selected from the group consisting of a fluoroalkyl group and a fluoro group (excluding a fluoro group in a fluoroalkyl group). (ii) A compound [Q] having a radiation-sensitive onium cation structure and an organic anion structure (excluding the polymer [P]) is further contained, and as the compound [Q], contained is a compound having a radiation-sensitive onium cation structure having two or more substituent groups [beta].

Description

Radiation-sensitive composition and resist pattern forming method

The present disclosure relates to a radiation-sensitive composition and a method for forming a resist pattern. [Cross-reference to related applications]

This application is based on Japanese Patent Application No. 2021-217962 for which it applied on December 25, 2020, and the content of description is used in this application.

In the lithography technique used in the manufacturing steps of various electronic devices such as semiconductor devices and liquid crystal devices, the radiation-sensitive composition is irradiated with far-ultraviolet rays such as ArF excimer lasers, extreme ultraviolet rays (Extreme Ultra-violet, EUV). ), electron beam, etc. to generate acid in the exposed part, and the chemical reaction of the generated acid participates in the exposure part and the unexposed part to cause a difference in the dissolution rate with respect to the developer, thereby forming a resist on the substrate. agent pattern.

Further miniaturization is rapidly advancing in various electronic device structures, and along with this, further miniaturization of the resist pattern in the lithography step is required. In addition, in response to such a demand, various studies have been conducted to improve the resolution of chemically amplified radiation-sensitive compositions used for microfabrication by lithography, the rectangularity of resist patterns, and the like (for example, refer to Patent Document 1). ). Patent Document 1 proposes a chemically amplified resist composition containing an acid generator containing a triaryl perionium cation having one or more fluorine atoms, and a resin containing a phenolic repeating unit of hydroxyl. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2014-2359

[The problem to be solved by the invention] In recent years, further miniaturization of resist patterns has been rapidly advanced, and attempts have been made, for example, to form patterns with a line width of 40 nm or less. Also in the case of forming such a fine resist pattern, it is required to form a resist pattern favorably with a small exposure amount (ie, high sensitivity).

Furthermore, for the radiation-sensitive composition used in the lithography step, it is required that the critical dimension uniformity (CDU) at the time of hole pattern formation is small, and the dissolution rate of the exposed part and the unexposed part with respect to the developing solution is small. The difference is sufficiently large and the development residue is small.

The present disclosure is made in view of the above-mentioned problems, and an object of the present disclosure is to provide a radiation-sensitive composition and a resist pattern forming method capable of forming a resist pattern with high sensitivity, small CDU, and suppressed occurrence of development defects. [Means of Solving Problems]

According to the present disclosure, the following means are provided. [1] A radiation-sensitive composition comprising a polymer [P] having a radiation-sensitive onium cation structure and an organic anion structure, and satisfying at least any one of the following (i) and (ii), (i) The polymer [P] contains at least one substituent selected from the group consisting of a fluoroalkyl group and a fluorine group (excluding the fluorine group in the fluoroalkyl group) having at least two β-radioactive onium cationic structure polymers; (ii) further containing a compound [Q] having a radiosensitive onium cation structure and an organic anion structure (except for the polymer [P]), and as the compound [Q], containing a compound having two or more The compound of the radioactive onium cation structure of the substituent β. [2] A method for forming a resist pattern, comprising: the step of forming a resist film on a substrate using the radiation-sensitive composition as described in [1]; the step of exposing the resist film; and A step of developing the exposed resist film. [Effect of invention]

According to the radiation-sensitive composition and the resist pattern forming method of the present disclosure, since the sensitivity is high, a favorable resist pattern can be formed with a small exposure amount. In addition, a resist pattern with small CDU and few development defects can be formed.

"Radiation Sensitive Composition" The radiation-sensitive composition of the present disclosure (hereinafter, also referred to as "the present composition") is a polymer composition containing a polymer (hereinafter, also referred to as "(A) polymer") serving as a base resin. In the present composition, a polymer [P] having a radioactive onium cation structure and an organic anion structure is contained as the (A) polymer or a component different from the (A) polymer. In the present composition, in particular, the polymer [P], or the compound [Q] having a radiosensitive onium cation structure and an organic anion structure (except for the polymer [P]), or both of these compounds have two The above radioactive onium cations of at least one group (hereinafter, also referred to as "substituent β") selected from the group consisting of a fluoroalkyl group and a fluorine group (excluding the fluorine group in the fluoroalkyl group) structure.

Specifically, this composition satisfies at least one of the following (i) and (ii). (i) The polymer [P] includes a polymer having a radiosensitive onium cation structure having two or more substituents β. (ii) The compound [Q] is further included, and as the compound [Q], a compound having a radiosensitive onium cation structure having two or more substituents β is included.

The polymer [P] may be a (A) polymer prepared as a base resin, or a compound (hereinafter, also referred to as "" acid-generating compounds"). The acid-generating compound is a compound in which the acid-generating structure typically has an organic anion structure (hereinafter, also simply referred to as an organic anion structure) derived from a structure having a radiosensitive onium cation and a conjugated base as an acid. The structure of the onium salt. The organic anion is usually an anion obtained by removing a proton from an acid group of an organic acid. The acid-generating compound is decomposed by radioactive onium cations by the action of radiation, the organic anion is freed, and the free organic anion and the hydrogen bond released from the components contained in the composition (for example, the acid-generating compound itself or the solvent) junction, thereby providing acid to the components contained in the composition. As an acid generating compound contained in this composition, (B) an acid generating agent and (C) an acid diffusion control agent are mentioned. In addition, the acid generating compound may be a polymer, or may be a compound different from the polymer (hereinafter, also referred to as a "low molecular weight compound"). The acid generating compound contained in the composition may be one type or two or more types.

In addition, hereafter, "the radiosensitive onium cation structure which has two or more substituents (beta)" is also called "specific cation structure [X]" for convenience. The specific cationic structure [X] may be the radioactive onium cationic structure possessed by the polymer [P] or the radioactive onium cationic structure possessed by the compound [Q]. In addition, the specific cationic structure [X] may constitute at least a part of the radiosensitive onium cationic structure in both the polymer [P] and the compound [Q].

As a specific aspect of the composition of the present composition containing the polymer [P] and the specific cationic structure [X], the aspects of the following <1> to <4> are mentioned, for example.

<1> Aspect: Contains (A) a polymer, (B) an acid generator, and (D) a solvent, and as the (A) polymer, contains a monomer derived from a monomer having a specific cationic structure [X] and A polymer of structural units of a monomer of organic anionic structure (equivalent to polymer [P]). <2> aspect: (A) polymer, (B) acid generator, and (D) solvent are included, and (A) polymer includes a monomer derived from a monomer having a radioactive onium cation structure and A polymer (corresponding to polymer [P]) of a structural unit of a monomer having an organic anion structure, and as the (B) acid generator, an onium salt containing a specific cation structure [X] and an organic anion structure is contained. <3> aspect: (A) polymer, (C) acid diffusion inhibitor, and (D) solvent are included, and (A) polymer includes a monomer derived from the following monomers, that is, having a radioactive onium cation structure A polymer (corresponding to polymer [P]) of a structural unit with a monomer having an organic anion structure, and as (C) an acid diffusion control agent, an onium salt containing a specific cation structure [X] and an organic anion structure is contained. <4> aspect: (A) polymer, (B) acid generator, and (D) solvent are contained, and (B) acid generator contains a monomer derived from the following monomers, that is, having a specific cationic structure [X] A polymer (equivalent to polymer [P]) of a structural unit of a monomer with an organic anion structure.

In addition, in the aspects of <1> to <4>, other components other than the components shown in each aspect may be further contained. For example, in the aspect of <1>, the (B) acid generator may further contain an onium salt having a specific cation structure [X] and an organic anion structure. In addition, in the aspects of <1>, <2>, and <4>, (C) an acid diffusion control agent may be further contained. In this case, the (C) acid diffusion control agent may contain an onium salt having a specific cation structure [X] and an organic anion structure, or may contain an onium salt having other organic cation structures and organic anion structures.

Furthermore, the aspect of the <2> may be the aspect of the following <2-1>, the aspect of the <3> may be the aspect of the following <3-1>, the aspect of the <4> The aspect may be the aspect of the following <4-1>. <2-1> Aspect: Contains (A) a polymer, (B) an acid generator, and (D) a solvent, and as the (A) polymer, contains a monomer derived from a monomer having only one substitution A polymer (equivalent to polymer [P]) of a structural unit of a monomer having a radiosensitive onium cationic structure (hereinafter, also referred to as "other organic cationic structure") and an organic anion structure with a β group or a radioactive onium cation structure without a substituent β , and as the (B) acid generator, an onium salt having a specific cation structure [X] and an organic anion structure is contained. <3-1> Aspect: Contains (A) a polymer, (C) an acid diffusion inhibitor, and (D) a solvent, and as the (A) polymer, contains a monomer derived from, that is, has another organic cationic structure A polymer (corresponding to polymer [P]) of a structural unit with a monomer having an organic anion structure, and as (C) an acid diffusion inhibitor, an onium salt having a specific cation structure [X] and an organic anion structure is contained. <4-1> Aspect: Contains (A) a polymer, (B) an acid generator, and (D) a solvent, and as the (A) polymer, contains no radioactive onium derived from the following monomers A polymer of a structural unit of a monomer having a cationic structure and an organic anionic structure, and as an acid generator (B), a structure including a monomer derived from a monomer having a specific cationic structure [X] and an organic anionic structure is contained unit of polymer (equivalent to polymer [P]).

Among the above, the aspects of <1> to <3> are preferable in terms of the sensitivity and CDU performance of the present composition being good and the development residue being small.

Hereinafter, the details of the specific cationic structure [X] will be described first.

<Specific cation structure [X]> The specific cation structure [X] is not particularly limited as long as it contains a radioactive onium cation structure having two or more substituents β. Among them, the specific cationic structure [X] preferably has a pericynium cationic structure or an iodonium cationic structure. The specific cationic structure [X] has preferably three or more substituents β in terms of maintaining the CDU performance of the composition and the dissolution contrast with respect to the developing solution at a high level and improving the sensitivity. Preferably, there are 4 or more. In addition, from the viewpoint of achieving a balance between the effect of improving sensitivity and the ease of synthesis, the number of substituents β possessed by the specific cationic structure [X] is preferably 10 or less, more preferably 8 or less, and still more preferably 7 or less, more preferably 6 or less. From the viewpoint of sensitivity, the substituent β is preferably at least one group selected from the group consisting of a fluoro group bonded to an aromatic ring and a fluoroalkyl group, and more preferably a fluoro group bonded to an aromatic ring.

Furthermore, when the specific cationic structure [X] has a fluoroalkyl group as the substituent β, the number of the fluoroalkyl groups in the specific cationic structure [X] is the number of the substituents β that the specific cationic structure [X] has. quantity. Therefore, for example, when the specific cationic structure [X] has two trifluoromethyl groups (—CF ₃ ), the number of the substituent β that the specific cationic structure [X] has is two. In addition, when the specific cationic structure [X] has one fluorine group (-F) and two trifluoromethyl groups (-CF ₃ ) bonded to the aromatic ring, the substitution of the specific cationic structure [X] The number of bases β is three.

The bonding position of the substituent β in the specific cationic structure [X] is not particularly limited. It is preferable that at least one of the substituents β contained in the specific cationic structure [X] is directly bonded to the aromatic ring contained in the specific cationic structure [X], since the effect of improving the sensitivity of the composition is high. , more preferably two or more substituents β are directly bonded to the aromatic ring. Among them, it is particularly preferable that the specific cationic structure [X] has one or two or more aromatic rings (hereinafter, also referred to as “aromatic rings Z”) bonded to periconium cations or iodonium cations, and two or more substitutions The group β is bonded to the same or different aromatic ring Z. That is, it is preferable that the specific cationic structure [X] has a structure in which two or more substituents β are bonded to one or more of the same aromatic rings in the aromatic ring Z having one or more aromatic rings, or It has a structure in which there are two or more aromatic rings Z, and one or more substituents β are each bonded to two or more different aromatic rings in the aromatic ring Z.

As the aromatic ring Z, a benzene ring, a naphthalene ring, an anthracene ring, etc. are mentioned, for example. Among these, the aromatic ring Z is preferably a benzene ring or a naphthalene ring, and particularly preferably a benzene ring. The number of the aromatic rings Z contained in the specific cationic structure [X] is not particularly limited, but is preferably one or more, and more preferably two or more. In the specific cationic structure [X], the description of the number of the substituents β which the specific cationic structure [X] has is applied regarding the total number of the substituents β bonded to the aromatic ring Z. That is, the total number of substituents β bonded to the aromatic ring Z is preferably 3 or more, and more preferably 4 or more. In addition, from the viewpoint of achieving a balance between the effect of improving sensitivity and ease of synthesis, the total number of substituents β bonded to the aromatic ring Z is preferably 10 or less, more preferably 8 or less, and still more preferably 7 number or less, more preferably six or less.

（式（1）中，R ^1a、R ^2a及R ^3a分別獨立地為氟基或氟烷基；R ^4a及R ^5a分別獨立地為一價取代基，或者表示連結R ^4a及R ^5a彼此結合而該些所鍵結的環的單鍵或二價基；R ^6a為一價取代基；a1為0～4的整數；a2及a3分別獨立地為0～5的整數；其中，滿足a1+a2+a3≧2；a4、a5及a6分別獨立地為0～3的整數；r為0或1；其中，滿足a1+a4≦4、a2+a5≦5、及a3+a6≦2×r+5；「*」表示鍵結鍵； 式（2）中，R ^7a及R ^8a分別獨立地為氟基或氟烷基；R ^9a及R ^10a分別獨立地為一價取代基；a7為0～5的整數；a8為0～4的整數；其中，滿足a7+a8≧2；a9及a10分別獨立地為0～3的整數；其中，滿足a7+a9≦5及a8+a10≦4；「*」表示鍵結鍵） Among them, the specific cation structure [X] preferably has a triaryl perionium cation structure or a diaryl iodonium cation structure. Specifically, the specific cation structure [X] is preferably a structure represented by the following formula (1) or a structure represented by the following formula (2). [hua 1]

(In formula (1), R ^1a , R ^2a and R ^3a are each independently a fluoro group or a fluoroalkyl group; R ^4a and R ^5a are each independently a monovalent substituent, or it means that R ^4a and R ^5a are bonded to each other And the single bond or divalent group of these bonded rings; R ^6a is a monovalent substituent; a1 is an integer of 0-4; a2 and a3 are independently an integer of 0-5; wherein, a1+ a2+a3≧2; a4, a5, and a6 are each independently an integer from 0 to 3; r is 0 or 1; wherein, a1+a4≦4, a2+a5≦5, and a3+a6≦2×r are satisfied +5; "*" represents a bond; in formula (2), R ^7a and R ^8a are each independently a fluoro group or a fluoroalkyl group; R ^9a and R ^10a are each independently a monovalent substituent; a7 is 0 an integer of ∼5; a8 is an integer from 0 to 4; wherein, a7+a8≧2 is satisfied; a9 and a10 are independently integers from 0 to 3; where a7+a9≦5 and a8+a10≦4 are satisfied; "*" indicates key bond)

In the above formulas (1) and (2), the fluoroalkyl groups of R ^1a , R ^2a , R ^3a , R ^7a and R ^8a may be linear or branched. The fluoroalkyl group preferably has 1 to 10 carbon atoms, and examples thereof include trifluoromethyl, 2,2,2-trifluoroethyl, perfluoroethyl, 2,2,3,3,3-pentafluoro Propyl, 1,1,1,3,3,3-hexafluoropropyl, perfluoron-propyl, perfluoroisopropyl, perfluoron-butyl, perfluoroisobutyl, perfluorotert-butyl , 2,2,3,3,4,4,5,5-octafluoropentyl, perfluorohexyl, etc. Among these, the fluoroalkyl groups of R ^1a , R ^2a , R ^3a , R ^7a and R ^8a are preferably groups having 1 to 5 carbon atoms, more preferably trifluoromethyl, 2,2,2-trifluoroethyl or perfluoroethyl.

Among the above, R ^1a , R ^2a , R ^3a , R ^7a and R ^8a are preferably fluoro, trifluoromethyl, 2,2,2-trifluoroethyl or perfluoroethyl, more preferably fluoro or a trifluoromethyl group, particularly preferably a fluoro group. By using an onium salt having a structure in which a fluorine group is directly bonded to an aromatic ring in a triaryl perionium cation structure or a diaryl iodonium cation structure, the sensitivity of the composition can be further improved, and the A composition excellent in CDU performance and development residue inhibiting property is suitable in this respect.

In the above formulas (1) and (2), the monovalent substituent represented by R ^4a , R ^5a , R ^6a , R ^9a and R ^10a is a group different from the substituent β. Specific examples of the monovalent substituent represented by R ^4a , R ^5a , R ^6a , R ^9a and R ^10a include a chloro group, a bromo group, an iodo group, a substituted or unsubstituted alkyl group (wherein, fluoroalkyl), substituted or unsubstituted alkoxy, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkyloxy, ester, alkylsulfonyl, Cycloalkylsulfonyl, hydroxyl, carboxyl, cyano, nitro, etc.

The alkyl group represented by R ^4a , R ^5a , R ^6a , R ^9a and R ^10a may be linear or branched. The alkyl group preferably has 1 to 10 carbon atoms, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl base, neopentyl, etc. Among these, the alkyl group of R ^4a , R ^5a , R ^6a , R ^9a and R ^10a preferably has 1 to 5 carbon atoms, more preferably methyl, ethyl, n-butyl or tert-butyl. When the alkyl group of R ^4a , R ^5a , R ^6a , R ^9a and R ^10a has a substituent, examples of the substituent include a chloro group, a bromo group, an iodo group, a hydroxyl group, a carboxyl group, a cyano group, Nitro, alkoxy having 1 to 5 carbon atoms, etc.

Specific examples when R ^4a , R ^5a , R ^6a , R ^9a , and R ^10a are substituted or unsubstituted alkoxy groups include those having the exemplified substituted or unsubstituted alkyl group. The alkoxy group is particularly preferably a methoxy group, an ethoxy group, an n-propoxy group or an n-butoxy group.

The cycloalkyl group represented by R ^4a , R ^5a , R ^6a , R ^9a and R ^10a may be either monocyclic or polycyclic. Among these, as a monocyclic cycloalkyl group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, etc. are mentioned, for example. As a polycyclic cycloalkyl group, a norbornyl group, an adamantyl group, a tricyclodecyl group, a tetracyclododecyl group, etc. are mentioned, for example. When the cycloalkyl group of R ^4a , R ^5a , R ^6a , R ^9a and R ^10a has a substituent, examples of the substituent include a chloro group, a bromo group, an iodo group, a hydroxyl group, a carboxyl group, and a cyano group. , nitro, alkoxy with 1 to 5 carbon atoms, etc.

As specific examples when R ^4a , R ^5a , R ^6a , R ^9a and R ^10a are substituted or unsubstituted cycloalkyloxy groups, the cycloalkyl group constituting the cycloalkyloxy group has the above-mentioned Exemplary substituted or unsubstituted cycloalkyl radicals. The alkoxy group is particularly preferably a cyclopentyloxy group or a cyclohexyloxy group.

When R ^4a , R ^5a , R ^6a , R ^9a , and R ^10a are ester groups (—COOR), the hydrocarbon moiety (R) of the ester group includes substituted or unsubstituted exemplified above. Alkyl, or substituted or unsubstituted cycloalkyl. Among these, when R ^4a , R ^5a , R ^6a , R ^9a and R ^10a are ester groups, methoxycarbonyl, ethoxycarbonyl, or n-butoxycarbonyl is preferred.

When R ^4a , R ^5a , R ^6a , R ^9a and R ^10a are an alkylsulfonyl group, the alkyl moiety constituting the alkylsulfonyl group may be substituted or unsubstituted as exemplified above. the alkyl group. When R ^4a , R ^5a , R ^6a , R ^9a and R ^10a are cycloalkylsulfonyl groups, the cycloalkyl moieties constituting the cycloalkylsulfonyl groups include the exemplified substituted or Unsubstituted cycloalkyl.

In the case of representing a divalent group linking the rings to which R ^4a and R ^5a are bonded to each other, examples of the divalent group include -COO-, -OCO-, -CO-, and -O. -, -SO-, -SO ₂ -, -S-, alkanediyl having 1 to 3 carbon atoms, alkenediyl having 2 or 3 carbon atoms, and -O-, -S-, -COO-, -OCO-, -CO-, -SO-, or -SO ₂ - group and the like. Among these, in the case of a single bond or a divalent group of a ring to which R ^4a and R ^5a are bonded to each other, R ^4a and R ^5a preferably form a single bond, -O- or - S-.

About a1, a2, and a3, the total number of these is 2 or more, More preferably, it is 3 or more, More preferably, it is 3-6, More preferably, it is 4-6. About a7 and a8, the total number of these is 2 or more, More preferably, it is 2-6.

The bonding bond (*) in the formula (1) and the formula (2) may be bonded to a hydrogen atom, or may be bonded to a monovalent group (a fluorine group, a hydroxyl group, an alkyl group, etc.). Alternatively, it may be bonded to an atom constituting the main chain or side chain of the polymer.

[化3]

[化4]

As a specific example of the specific cation structure [X], the structure represented by the following formula, the structure which removed one arbitrary hydrogen atom from the benzene ring which the organic cation represented by the following formula has, etc. are mentioned, for example. However, the specific cation structure [X] is not limited to the following structures. [hua 2]

[hua 3]

[hua 4]

The organic anion serving as the counter ion of the specific cation structure [X] is not particularly limited as long as it has a structure capable of generating an acid by irradiation with radiation. As a structure which this organic anion has, a sulfonate anion structure, an imide anion structure, a methyl anion structure, a carboxylate anion structure, etc. are mentioned, for example. Among these, the organic anion preferably has a sulfonate anion structure or a carboxylate anion structure.

<About the specific aspect of the composition> A preferable aspect of the present composition is a polymer composition containing (A) a polymer and (B) an acid generator, and may further contain (C) an acid diffusion control agent and (D) a solvent as suitable components and (E) one or more of high fluorine-containing polymers. Hereinafter, each component will be described in detail.

<(A) Polymer> (A) The polymer is a component constituting the base resin of the present composition. As the polymer (A), a structural unit having an acid dissociable group (hereinafter, also referred to as "structural unit (I)") and a structural unit having a hydroxyl group bonded to an aromatic ring (hereinafter, also referred to as "structural unit (I)") are usually used. A polymer of at least one of "structural unit (II)"). Here, in this specification, a "base resin" means a component which occupies 40 mass % or more with respect to the total amount of solid content contained in this composition, Preferably it is a component which occupies 50 mass % or more. (A) The polymer may be composed of only one kind, or may be composed of two or more kinds. In addition, in this specification, "the total amount of solid content" means the sum total of the components other than (D) a solvent.

[Structural unit (I)] The structural unit (I) is a structural unit having an acid dissociable group. The "acid-dissociable group" refers to a group that substituted a hydrogen atom of an acid group such as a carboxyl group and a hydroxyl group, and is a group that is dissociated by the action of an acid. By making this composition contain a polymer having an acid dissociable group, the acid dissociable group is dissociated by an acid generated by exposure to generate an acid group such as a carboxyl group or a hydroxyl group, and the polymer (A) can be added to the developer. changes in solubility. Thereby, favorable lithography characteristics can be given to this composition, and a favorable resist pattern can be formed, and it is suitable in this respect.

（式（i-1）中，R ¹²為氫原子、氟基、甲基或三氟甲基；R ¹³為碳數1～20的一價烴基；R ¹⁴及R ¹⁵分別獨立地為碳數1～20的一價烴基，或者表示R ¹⁴及R ¹⁵彼此結合並與R ¹⁴及R ¹⁵所鍵結的碳原子一同構成的碳數3～20的脂環式結構； 式（i-2）中，R ¹⁶為氫原子或甲基；L ³為單鍵、-COO-或-CONH-；R ¹⁷、R ¹⁸及R ¹⁹分別獨立地為氫原子、碳數1～20的一價烴基、或碳數1～20的一價氧基烴基） The structural unit (I) is not particularly limited as long as it has an acid dissociable group. Specific examples of the structural unit (I) include a structural unit represented by the following formula (i-1) (hereinafter, also referred to as "structural unit (I-1)") and the following formula (i-2 ) (hereinafter, also referred to as "structural unit (I-2)") and the like. [hua 5]

(In formula (i-1), R ¹² is a hydrogen atom, a fluorine group, a methyl group or a trifluoromethyl group; R ¹³ is a monovalent hydrocarbon group having 1 to 20 carbon atoms; R ¹⁴ and R ¹⁵ are each independently a carbon number A monovalent hydrocarbon group of 1 to 20, or an alicyclic structure of 3 to 20 carbon atoms composed of R ¹⁴ and R ¹⁵ bonded to each other and together with the carbon atoms to which R ¹⁴ and R ¹⁵ are bonded; Formula (i-2) wherein, R ¹⁶ is a hydrogen atom or a methyl group; L ³ is a single bond, -COO- or -CONH-; R ¹⁷ , R ¹⁸ and R ¹⁹ are independently a hydrogen atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a monovalent oxyhydrocarbon group with a carbon number of 1 to 20)

In the above formulas (i-1) and (i-2), R ¹² is preferably a hydrogen atom or a methyl group, more preferably from the viewpoint of the copolymerizability of the monomer providing the structural unit (I-1). is methyl. From the viewpoint of copolymerizability of the monomer providing the structural unit (I-2), R ¹⁶ is preferably a hydrogen atom.

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ¹³ to R ¹⁵ and R ¹⁷ to R ¹⁹ include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, and a monovalent lipid group having 3 to 20 carbon atoms. Cyclic hydrocarbon group, monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and the like. Specific examples of these include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, Alkyl such as tert-butyl and pentyl; alkenyl such as vinyl, propenyl, butenyl and pentenyl; alkynyl such as ethynyl, propynyl, butynyl, pentynyl and the like.

Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include monocyclic alicyclic saturated hydrocarbon groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; norbornyl, adamantyl, tricyclic Polycyclic alicyclic saturated hydrocarbon groups such as decyl and tetracyclododecyl; monocyclic alicyclic unsaturated hydrocarbon groups such as cyclopropenyl, cyclobutenyl, cyclopentenyl, and cyclohexenyl; norbornenyl, Polycyclic alicyclic saturated hydrocarbon groups such as tricyclodecenyl and the like. Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include aryl groups such as phenyl, tolyl, xylyl, naphthyl, and anthracenyl; benzyl, phenethyl, naphthylmethyl, and anthracenylmethyl. Alkyl and other aralkyl groups, etc.

Examples of the alicyclic structure having 3 to 20 carbon atoms in which R ¹⁴ and R ¹⁵ are bonded to each other and together with the carbon atoms to which R ¹⁴ and R ¹⁵ are bonded include a cyclopropane structure, a cyclobutane structure, and a cyclopentane structure. , cyclohexane structure, cycloheptane structure, cyclooctane structure and other monocyclic alicyclic structures; norbornane structure, adamantane structure, tricyclodecane structure, tetracyclododecane structure and other polycyclic alicyclic structures structure, etc. Examples of the monovalent oxyhydrocarbon group having 1 to 20 carbon atoms represented by R ¹⁷ , R ¹⁸ and R ¹⁹ include, for example, one of the above-mentioned R ¹³ to R ¹⁵ and R ¹⁷ to R ¹⁹ having 1 to 20 carbon atoms. The group exemplified as a valent hydrocarbon group includes a group in which an oxygen atom is included in the terminal on the side of the bond. Among these, R ¹⁷ , R ¹⁸ and R ¹⁹ are preferably a chain hydrocarbon group and a cycloalkyloxy group.

[化7]

（式中，R ^A1為氫原子、氟基、甲基或三氟甲基） As a specific example of a structural unit (I-1), the structural unit etc. which are represented, for example by the following formula are mentioned. [hua 6]

[hua 7]

(In the formula, R ^A1 is a hydrogen atom, a fluorine group, a methyl group or a trifluoromethyl group)

（式中，R ¹⁶為氫原子或甲基） As a specific example of a structural unit (I-2), the structural unit etc. which are represented, for example by the following formula are mentioned. [hua 8]

(in the formula, R ¹⁶ is a hydrogen atom or a methyl group)

The content ratio of the structural unit (I) is preferably 20 mol % or more, more preferably 30 mol % or more, and still more preferably 35 mol % or more with respect to all the structural units constituting the (A) polymer. In addition, the content ratio of the structural unit (I) is preferably 80 mol % or less, more preferably 70 mol % or less, and still more preferably 65 mol % or less with respect to all the structural units constituting the polymer (A). By setting the content ratio of the structural unit (I) to the above-mentioned range, the difference in the dissolution rate of the exposed portion and the unexposed portion with respect to the developer can be sufficiently increased, and the pattern shape of the resist film can be made good. suitable.

[Structural unit (II)] The structural unit (II) is a structural unit having a hydroxyl group bonded to an aromatic ring. By introducing the structural unit (II) into the polymer (A), the lithography characteristics (Line Width Roughness (LWR) performance, CDU performance, etc.) of the composition can be sufficiently improved, and in this respect suitable.

（式（ii）中，R ¹為氫原子、氟基、甲基或三氟甲基；L ²為單鍵、-O-、-CO-、-COO-或-CONH-；Y ¹為具有與芳香環鍵結的羥基的一價基） As an aromatic ring which a structural unit (II) has, a benzene ring, a naphthalene ring, an anthracene ring, etc. are mentioned, for example. Among these, a benzene ring or a naphthalene ring is preferable, and a benzene ring is more preferable. In the structural unit (II), the number of hydroxyl groups bonded to the aromatic ring is not particularly limited, but is preferably one to three, and more preferably one or two. As a structural unit (II), the structural unit represented by following formula (ii) is mentioned, for example. [Chemical 9]

(In formula (ii), R ¹ is a hydrogen atom, a fluoro group, a methyl group or a trifluoromethyl group; L ² is a single bond, -O-, -CO-, -COO- or -CONH-; Y ¹ is a A monovalent group of a hydroxyl group bonded to an aromatic ring)

In the formula (ii), R ¹ is preferably a hydrogen atom or a methyl group from the viewpoint of the copolymerizability of the monomer providing the structural unit (II). L ² is preferably a single bond or -COO-.

（式（1-1）～式（1-12）中，R ¹為氫原子、氟基、甲基或三氟甲基） As a specific example of a structural unit (II), the structural unit etc. each represented by following formula (1-1) - formula (1-12) are mentioned. [Chemical 10]

(In formulas (1-1) to (1-12), R ¹ is a hydrogen atom, a fluoro group, a methyl group or a trifluoromethyl group)

The ratio of the structural unit (II) in the polymer (A) is preferably 5 mol % or more, more preferably 10 mol % or more, and further preferably 20 mol % with respect to all the structural units constituting the (A) polymer. ear % or more. In addition, the ratio of the structural unit (II) is preferably 80 mol % or less, more preferably 70 mol % or less, and still more preferably 60 mol % or less with respect to all the structural units constituting the polymer (A). By setting the ratio of the structural unit (II) to the above-mentioned range, the lithography characteristics (LWR performance, CDU performance, etc.) of the present composition can be sufficiently improved, which is preferable in this respect.

In addition, the polymer which has a structural unit (II) different from the polymer which has a structural unit (I) may be contained in this composition. As a specific aspect of the present composition in this case, a polymer including a structural unit (I) but not having a structural unit (II), and a polymer having a structural unit (II) but not having a structural unit (I) can be mentioned. ) of the polymer; aspects of the polymer containing the structural unit (I) and the structural unit (II), and the polymer having the structural unit (II) but not having the structural unit (I), etc. From the viewpoint of obtaining a composition excellent in lithography properties such as defect suppression, LWR performance, and CDU performance, it is preferable that the present composition contains at least a polymer having a structural unit (I) and a structural unit (II) as (A) )polymer.

[Other Structural Units] (A) The polymer may further have a structural unit (hereinafter, also referred to as "other structural unit") different from the structural unit (I) and the structural unit (II). Examples of other structural units include structural units (III) having a radioactive onium cation structure and an organic anion structure, and those having at least any one of a lactone structure, a cyclic carbonate structure, and a sultone structure. Structural unit (IV), structural unit (V) having an alcoholic hydroxyl group, and the like.

（式（3A）中，L ⁷為參與聚合的基；「L ⁷-Z ⁺」為感放射線性鎓陽離子；「M ^-」為有機陰離子；式（3B）中，L ⁷為參與聚合的基；「Z ⁺」為感放射線性鎓陽離子；「L ⁷-M ^-」為有機陰離子） • Structural unit (III) The structural unit (III) is typically a structural unit derived from an onium salt having a group participating in polymerization (preferably a group containing a polymerizable carbon-carbon unsaturated bond). Specifically, the structural unit (III) can be represented as a structural unit derived from a monomer represented by the following formula (3A) or formula (3B). [Chemical 11]

(In formula (3A), L ⁷ is a group participating in polymerization; "L ⁷ -Z ⁺ " is a radioactive onium cation; "M ^- " is an organic anion; in formula (3B), L ⁷ is a group participating in polymerization ; "Z ⁺ " is a radioactive onium cation; "L ⁷ -M ^- " is an organic anion)

In the above formula (3A) and formula (3B), the group represented by L ⁷ is preferably a group containing a polymerizable carbon-carbon unsaturated bond. Specific examples of the polymerizable carbon-carbon unsaturated bond possessed by L ⁷ include those contained in vinyl groups, vinyl ether groups, vinyl phenyl groups, (meth)acryloyl groups, and maleimide groups. of carbon-carbon unsaturated bonds.

Among these, the structural unit (III) is preferably a structural unit derived from the monomer represented by the above-mentioned formula (3B) from the viewpoint of the easiness of polymer synthesis.

The radiosensitive onium cation contained in the monomer constituting the structural unit (III) may be a radiosensitive onium cation having two or more substituents β, or may have only one substituent β or no substituents β radiation-sensitive onium cations (hereinafter, also referred to as "other organic cations"). As the monomer constituting the structural unit (III), the following monomer [A1] and monomer [A2] can be mentioned. [A1] Monomer: including a radiosensitive onium cation having two or more substituents β and an organic anion, and any one of the radioactive onium cation and organic anion having two or more substituents β is involved in polymerization the base. [A2] Monomer: contains other organic cations and organic anions, and any one of the other organic cations and organic anions contains a group participating in polymerization.

The polymer [P] is preferably a polymer having a structural unit (I) and a structural unit (III), since the effect of reducing the development residue can be further improved, and the sensitivity of the composition can be improved. More preferably, it is a polymer which has a structural unit (I), a structural unit (II), and a structural unit (III).

（式（iii-1）中，R ²⁰為氫原子或甲基；L ⁴為單鍵、-O-或-COO-；R ²³為碳數1～6的經取代或未經取代的烷二基、碳數2～6的經取代或未經取代的烯二基、或碳數6～12的經取代或未經取代的伸芳基；R ²¹及R ²²分別獨立地為碳數1～12的經取代或未經取代的烷基、碳數2～12的經取代或未經取代的烯基、或碳數6～20的經取代或未經取代的芳基；「M ^-」為有機陰離子； 式（iii-2）中，R ²⁰為氫原子或甲基；L ⁵為單鍵、-R ^30a-CO-O-、-R ^30a-O-或-R ^30a-O-CO-；R ^30a為碳數1～12的烷二基、或於碳數2～12的烷二基的碳-碳鍵間包含-O-、-CO-或-COO-的二價基；R ²⁴為氫原子、碳數1～10的烷基、或碳數1～10的氟烷基；Y ⁺為下述式（Y-1）或式（Y-2）所表示的感放射線性鎓陽離子； 式（iii-3）中，R ²⁰為氫原子或甲基；L ⁶為單鍵、碳數1～6的經取代或未經取代的烷二基、碳數2～6的經取代或未經取代的烯二基、碳數6～12的經取代或未經取代的伸芳基、-CO-O-R ^30b-、或-CO-NH-R ^30b-；R ^30b為碳數1～6的經取代或未經取代的烷二基、或於碳數2～6的烷二基的碳-碳鍵間包含-O-、-CO-或-COO-的二價基；Y ⁺為下述式（Y-1）或式（Y-2）所表示的感放射線性鎓陽離子） [化13]

（式（Y-1）及式（Y-2）中，R ²⁵～R ²⁹分別獨立地為碳數1～12的經取代或未經取代的烷基、碳數2～12的經取代或未經取代的烯基、或碳數6～20的經取代或未經取代的芳基） Preferable examples of the structural unit (III) include a structural unit represented by the following formula (iii-1), a structural unit represented by the following formula (iii-2), and the following formula (iii-3) represented structural unit. [Chemical 12]

(In formula (iii-1), R ²⁰ is a hydrogen atom or a methyl group; L ⁴ is a single bond, -O- or -COO-; R ²³ is a substituted or unsubstituted alkanedi having 1 to 6 carbon atoms base, substituted or unsubstituted alkenediyl group with 2-6 carbon atoms, or substituted or unsubstituted aryl group with 6-12 carbon atoms; R ²¹ and R ²² are each independently carbon number 1- A substituted or unsubstituted alkyl group of 12, a substituted or unsubstituted alkenyl group of 2 to 12 carbon atoms, or a substituted or unsubstituted aryl group of 6 to 20 carbon atoms; "M ^- " is Organic anion; In formula (iii-2), R ²⁰ is a hydrogen atom or a methyl group; L ⁵ is a single bond, -R ^30a -CO-O-, -R ^30a -O- or -R ^30a -O-CO- ; R ^30a is an alkanediyl group with 1 to 12 carbon atoms, or a divalent group containing -O-, -CO- or -COO- between the carbon-carbon bonds of an alkanediyl group with a carbon number of 2 to 12; R ²⁴ is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a fluoroalkyl group having 1 to 10 carbon atoms; Y ⁺ is a radioactive onium cation represented by the following formula (Y-1) or formula (Y-2) ; In formula (iii-3), R ²⁰ is a hydrogen atom or a methyl group; L ⁶ is a single bond, a substituted or unsubstituted alkanediyl group with 1 to 6 carbon atoms, a substituted or unsubstituted alkanediyl group with 2 to 6 carbon atoms Unsubstituted alkenediyl, substituted or unsubstituted arylidene with 6-12 carbon atoms, -CO-OR ^30b -, or -CO-NH-R ^30b -; R ^30b is carbon number 1-6 substituted or unsubstituted alkanediyl, or a divalent group containing -O-, -CO- or -COO- between the carbon-carbon bonds of alkanediyl with 2 to 6 carbon atoms; Y ⁺ is the following The radiation-sensitive onium cation represented by the formula (Y-1) or the formula (Y-2)) [Chemical 13]

(In formula (Y-1) and formula (Y-2), R ²⁵ to R ²⁹ are each independently a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alkyl group having 2 to 12 carbon atoms. unsubstituted alkenyl, or substituted or unsubstituted aryl with 6 to 20 carbon atoms)

In the above formulas (iii-1) to (iii-3), and the above formulas (Y-1) and (Y-2), the groups in each of R ²¹ to R ²³ and R ²⁵ to R ²⁹ are: In the case of a substituted alkyl group, a substituted alkenyl group, or a substituted aryl group, examples of the substituent include a fluoro group, a chloro group, a bromo group, an iodo group, an alkoxy group, and a cycloalkyloxy group. group, ester group, alkylsulfonyl group, cycloalkylsulfonyl group, hydroxyl, carboxyl group, cyano group, nitro group, acetyl group, fluoroacetyl group, etc.

The organic cation in the monomer constituting the structural unit represented by the formula (iii-1) and the organic cation represented by the formula (Y-1) preferably have a triaryl perionium cation structure. It is preferable that the organic cation in the monomer which comprises the structural unit represented by the said formula (iii-2) and formula (iii-3) has a triaryl perionium cation structure or a diaryl iodonium cation structure. The organic cation represented by the formula (Y-2) preferably has a diaryl iodonium cation structure. Having a specific cation in the monomer constituting the structural unit represented by the formula (iii-1), the structural unit represented by the formula (iii-2), and the structural unit represented by the formula (iii-3) In the case of the structure [X], as a specific example of the specific cationic structure [X], the structures exemplified above are exemplified.

（式（iii-1a）～式（iii-9a）中，R ²⁰為氫原子或甲基；Y ⁺為所述式（Y-1）或式（Y-2）所表示的感放射線性鎓陽離子；M ^-為有機陰離子） Specific examples of the structural unit (III) include, for example, structures represented by the following formulae (iii-1a) to (iii-7a) as the structural unit having a partial structure represented by the above formula (3B). unit etc. As a structural unit which has a partial structure represented by the said formula (3A), the structural unit etc. which are respectively represented by following formula (iii-8a) and formula (iii-9a) are mentioned. [Chemical 14]

(In formulas (iii-1a) to (iii-9a), R ²⁰ is a hydrogen atom or a methyl group; Y ⁺ is the radioactive onium represented by the formula (Y-1) or the formula (Y-2) Cation; M ^- is an organic anion)

In the case where the polymer (A) contains the structural unit (III), the content ratio of the structural unit (III) is preferably 3 mol % or more, more preferably 5 mol % with respect to all the structural units constituting the (A) polymer. mol% or more, more preferably 10 mol% or more. In addition, the content ratio of the structural unit (III) is preferably 50 mol % or less, more preferably 35 mol % or less, and still more preferably 25 mol % or less with respect to all the structural units constituting the polymer (A). By setting the content ratio of the structural unit (III) to the above-mentioned range, the reduction in resolution due to acid diffusion can be suppressed, and as a result, the lithography properties of the present composition can be further improved, which is suitable in this respect.

Structural unit (IV) The structural unit (IV) is a structural unit having a lactone structure, a cyclic carbonate structure, a sultone structure, or a cyclic structure in which two or more of these are combined (wherein, it corresponds to the structural unit (I) ~ except for structural unit (III)). Since the polymer (A) further contains the structural unit (IV), the solubility in the developer can be adjusted, and as a result, the lithography characteristics of the present composition can be further improved, which is suitable in this respect. In addition, when the polymer (A) further contains the structural unit (IV), the adhesion between the resist film obtained by using the present composition and the substrate can be improved.

[化16]

[化17]

[化18]

（式中，R ^L1為氫原子、氟基、甲基或三氟甲基） As a structural unit (IV), the structural unit etc. which are represented by the following formula are mentioned, for example. [Chemical 15]

[Chemical 16]

[Chemical 17]

[Chemical 18]

(In the formula, R ^L1 is a hydrogen atom, a fluorine group, a methyl group or a trifluoromethyl group)

When the polymer (A) contains the structural unit (IV), the content of the structural unit (IV) is preferably 5 mol % or more, more preferably 10 mol % or more with respect to all the structural units constituting the (A) polymer. mol% or more, more preferably 15 mol% or more. In addition, the content ratio of the structural unit (IV) is preferably 50 mol % or less, more preferably 40 mol % or less, and still more preferably 30 mol % or less with respect to all the structural units constituting the polymer (A). By setting the content ratio of the structural unit (IV) to the above-mentioned range, the lithography characteristics of the composition can be improved, and the adhesion between the resist film obtained by using the composition and the substrate can be improved. suitable.

· Structural unit (V) The structural unit (V) is a structural unit having an alcoholic hydroxyl group (however, those corresponding to the structural unit (I) to the structural unit (IV) are excluded). Here, in the present specification, the "alcoholic hydroxyl group" refers to a group having a structure in which a hydroxyl group and an aliphatic hydrocarbon group are directly bonded. The aliphatic hydrocarbon group may be a chain hydrocarbon group or an alicyclic hydrocarbon group. Since the polymer (A) further has the structural unit (V), the solubility in the developer can be improved, and as a result, the lithography characteristics of the present composition can be further improved, which is suitable in this respect.

The structural unit (V) is preferably a structural unit derived from an unsaturated monomer having an alcoholic hydroxyl group. Although it does not specifically limit as this unsaturated monomer, For example, 3-hydroxyadamantan-1-yl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, etc. are mentioned.

When the polymer (A) has a structural unit (V), the content of the structural unit (V) is preferably 1 mol % or more, more preferably 3 mol % or more with respect to all the structural units constituting the (A) polymer. More than mol%. In addition, the content ratio of the structural unit (V) is preferably 30 mol % or less, more preferably 10 mol % or less, with respect to all the structural units constituting the polymer (A).

As other structural units, in addition to the above, for example, a structural unit containing a cyano group, a nitro group, or a sulfonamido group (for example, derived from 2-cyanomethyladamantan-2-yl (meth)acrylic acid) can be mentioned. Structural units of esters, etc.), structural units containing halogen atoms (for example, structural units derived from 2,2,2-trifluoroethyl (meth)acrylate, 1,1,1, Structural unit of 3,3,3-hexafluoropropan-2-yl ester, structural unit derived from 4-iodostyrene, etc.), structural unit containing non-acid dissociable hydrocarbon group (for example, structural unit derived from styrene , structural units derived from vinylnaphthalene, structural units derived from n-amyl (meth)acrylate, etc.). The content ratio of these structural units can be suitably set according to each structural unit within the range which does not impair the effect of this disclosure.

The content of the polymer (A) in the present composition is preferably 50% by mass or more, more preferably 70% by mass or more, and still more preferably 80% by mass with respect to the total amount of the solid content contained in the composition. above. In addition, the content ratio of the polymer (A) is preferably 99% by mass or less, more preferably 98% by mass or less, and still more preferably 95% by mass or less with respect to the total amount of the solid content contained in the composition. By setting the ratio of the polymer (A) to the total amount of the solid content contained in the composition within the above-mentioned range, the composition can have good sensitivity and CDU performance, and can sufficiently suppress development residues. It is suitable in this respect to improve the effect.

Moreover, when (A) polymer contains the polymer (namely polymer [P]) which has structural unit (III), (A) with respect to the total amount of (A) polymer contained in this composition ) The ratio of the polymer [P] in the polymer is preferably 10 mass % or more, more preferably 20 mass % or more, still more preferably 40 mass % or more, still more preferably 50 mass % or more, particularly preferably 70 mass % %above.

<Synthesis of polymers> (A) The polymer can be synthesized, for example, by using a radical polymerization initiator or the like to polymerize the monomer that provides each structural unit in an appropriate solvent.

As a radical polymerization initiator, for example, 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 bis Azo-based radical initiators such as methyl ester; peroxide-based 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. As the radical polymerization initiator, one kind can be used alone or two or more kinds can be used in combination.

Examples of solvents used in the polymerization include alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane; cyclohexane, cycloheptane, cyclooctane, Naphthalene, norbornane and other naphthenes; benzene, toluene, xylene, ethylbenzene, cumene and other aromatic hydrocarbons; chlorobutane, bromohexane, dichloroethane, hexamethylene Halogenated hydrocarbons such as hexamethylene dibromide and chlorobenzene; saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, isobutyl acetate, methyl propionate; acetone, butanone, 4-methyl- 2-pentanone, 2-heptanone and other ketones; tetrahydrofuran, dimethoxyethane, diethoxyethane and other ethers; methanol, ethanol, 1-propanol, 2-propanol, 4- Alcohols such as methyl-2-pentanol, etc. As the solvent used for these polymerizations, one type may be used alone or two or more types may be used in combination.

The reaction temperature in the polymerization is preferably 40°C or higher, more preferably 50°C or higher. In addition, the reaction temperature is preferably 150°C or lower, more preferably 120°C or lower. The reaction time in the polymerization is preferably 1 hour or more, more preferably 2 hours or more. In addition, the reaction time is preferably 48 hours or less, more preferably 24 hours or less.

(A) The polystyrene-equivalent weight average molecular weight (Mw) of the polymer obtained by gel permeation chromatography (GPC) is preferably 1,000 or more, more preferably 2,000 or more, and still more preferably 3,000 or more, especially 5,000 or more. Moreover, Mw is preferably 50,000 or less, more preferably 30,000 or less, still more preferably 20,000 or less, and particularly preferably 10,000 or less. By making the Mw of the (A) polymer into the above-mentioned range, the coating properties of the present composition can be improved, and development defects can be sufficiently suppressed, which is suitable in this respect.

(A) The ratio (Mw/Mn) of Mw of the polymer to the polystyrene conversion number average molecular weight (Mn) obtained by GPC is preferably 5.0 or less, more preferably 3.0 or less, and still more preferably 2.0 or less. Moreover, Mw/Mn is 1 or more normally, Preferably it is 1.3 or more.

<(B) Acid generator> (B) The acid generator typically contains a radioactive onium cation structure and an organic anion structure. The (B) acid generator may be a low molecular compound or a polymer (except for the (A) polymer).

Specific examples when the (B) acid generator is a low molecular weight compound include the following onium salts [LB1] and onium salts [LB2]. [LB1] Onium salt: Contains a radiosensitive onium cation (specific cation structure [X]) having two or more substituents β and an organic anion. [LB2] Onium salt: Contains a radiosensitive onium cation (other organic cation) with only one substituent β or no substituent β and an organic anion.

·Specific cation structure [X] In the onium salt [LB1], examples of the specific cation structure [X] include a radioactive onium cation having a partial structure represented by the above formula (1), and a moiety having a partial structure represented by the above formula (2). Structure of radiosensitive onium cations. Specific examples of these include the radiation-sensitive onium cations exemplified in the descriptions of the above-mentioned formulas (1) and (2).

（式（4）中，R ³¹及R ³²分別獨立地為碳數1～20的一價有機基；k1為0～5的整數；於k1為1的情況下，R ³³為碳數1～20的一價有機基、羥基、硝基或鹵素基；於k1為2以上的情況下，多個R ³³相同或不同，為碳數1～20的一價有機基、羥基、硝基或鹵素基，或者表示多個R ³³中的2個以上彼此結合並與該些所鍵結的碳鏈一同構成的環員數4～20的環結構的一部分；t1為0或1；其中，式（4）中，取代基β的數量為0個或1個； 式（5）中，k2為0～7的整數；於k2為1的情況下，R ³⁴為碳數1～20的一價有機基、羥基、硝基或鹵素基；於k2為2以上的情況下，多個R ³⁴相同或不同，為碳數1～20的一價有機基、羥基、硝基或鹵素基，或者表示多個R ³⁴中的2個以上彼此結合並與該些所鍵結的碳鏈一同構成的環員數4～20的環結構的一部分；k3為0～6的整數；於k3為1的情況下，R ³⁵為碳數1～20的一價有機基、羥基、硝基或鹵素基；於k3為2以上的情況下，多個R ³⁵相同或不同，為碳數1～20的一價有機基、羥基、硝基或鹵素基，或者表示多個R ³⁵中的2個以上彼此結合並與該些所鍵結的碳鏈一同構成的環員數3～20的環結構的一部分；t3為0～3的整數；R ³⁶為單鍵或碳數1～20的二價有機基；t2為0或1；其中，式（5）中，取代基β的數量為0個或1個； 式（6）中，k4為0～5的整數；於k4為1的情況下，R ³⁷為碳數1～20的一價有機基、羥基、硝基或鹵素基；於k4為2以上的情況下，多個R ³⁷相同或不同，為碳數1～20的一價有機基、羥基、硝基或鹵素基，或者表示多個R ³⁷中的2個以上彼此結合並與該些所鍵結的碳鏈一同構成的環員數4～20的環結構的一部分；k5為0～5的整數；於k5為1的情況下，R ³⁸為碳數1～20的一價有機基、羥基、硝基或鹵素基；於k5為2以上的情況下，多個R ³⁸相同或不同，為碳數1～20的一價有機基、羥基、硝基或鹵素基，或者表示多個R ³⁸中的2個以上彼此結合並與該些所鍵結的碳鏈一同構成的環員數4～20的環結構的一部分；其中，式（6）中，取代基β的數量為0個或1個） ·Other organic cations In the onium salt [LB2], the structure of the other organic cations is not particularly limited as long as it is a radiosensitive onium cation having no substituent β or having only one substituent β. The other organic cation preferably has a pericynium cation structure or an iodonium cation structure from the viewpoint of making the lithography characteristics of the present composition good. Specifically, an organic cation represented by the following formula (4), an organic cation represented by the following formula (5), an organic cation represented by the following formula (6), and the like are exemplified. [Chemical 19]

(In formula (4), R ³¹ and R ³² are each independently a monovalent organic group having 1 to 20 carbon atoms; k1 is an integer of 0 to 5; when k1 is 1, R ³³ is a carbon number of 1 to 1 20 monovalent organic group, hydroxyl group, nitro group or halogen group; when k1 is 2 or more, multiple R ³³ are the same or different, and are monovalent organic group, hydroxyl group, nitro group or halogen group with carbon number 1-20 group, or represents a part of a ring structure with 4 to 20 ring members in which two or more of the plurality of R ³³ are bonded to each other and together with these bonded carbon chains; t1 is 0 or 1; wherein, the formula ( In 4), the number of substituent β is 0 or 1; In formula (5), k2 is an integer of 0 to 7; when k2 is 1, R ³⁴ is a monovalent organic carbon number of 1 to 20 group, hydroxyl group, nitro group or halogen group; when k2 is 2 or more, a plurality of R ³⁴ are the same or different, and represent a monovalent organic group with 1 to 20 carbon atoms, a hydroxyl group, a nitro group or a halogen group, or represent a polyvalent organic group. A part of a ring structure with 4 to 20 ring members that two or more of the R ³⁴ are bonded to each other and together with these bonded carbon chains; k3 is an integer of 0 to 6; when k3 is 1 , R ³⁵ is a monovalent organic group with a carbon number of 1-20, a hydroxyl group, a nitro group or a halogen group; when k3 is 2 or more, multiple R ³⁵ are the same or different, and are a monovalent organic group with a carbon number of 1-20 group, hydroxyl group, nitro group, or halogen group, or a part of a ring structure with 3 to 20 ring members formed by two or more of a plurality of R ³⁵ bonded to each other and together with these bonded carbon chains; t3 is an integer of 0 to 3; R ³⁶ is a single bond or a divalent organic group with 1 to 20 carbon atoms; t2 is 0 or 1; wherein, in formula (5), the number of substituent β is 0 or 1; In (6), k4 is an integer of 0 to 5; when k4 is 1, R ³⁷ is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, a nitro group or a halogen group; when k4 is 2 or more In the following, a plurality of R ³⁷ are the same or different, and are a monovalent organic group with 1 to 20 carbon atoms, a hydroxyl group, a nitro group or a halogen group, or two or more of the plurality of R ³⁷ are bonded to each other and to these A part of the ring structure with 4 to 20 ring members formed by the carbon chain together; k5 is an integer of 0 to 5; when k5 is 1, R ³⁸ is a monovalent organic group with 1 to 20 carbon atoms, a hydroxyl group, Nitro group or halogen group; when k5 is 2 or more, a plurality of R ³⁸ are the same or different, and are a monovalent organic group with 1 to 20 carbon atoms, a hydroxyl group, a nitro group or a halogen group, or represent a plurality of R ³⁸ A part of a ring structure with 4 to 20 ring members formed by combining two or more of the bonded carbon chains with each other; wherein, in formula (6), the number of substituent β is 0 or 1 )

In the formula (4), the monovalent organic group having 1 to 20 carbon atoms represented by R ³¹ , R ³² and R ³³ is preferably a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a hydrogen atom substituted with a substituent. A hydrocarbon group having 1 to 20 carbon atoms, more preferably a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms in which hydrogen atoms are substituted with a substituent, and more preferably a substituted or unsubstituted hydrocarbon group Substituted phenyl. In addition, as the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ³¹ , R ³² and R ³³ , for example, those represented by the above formulas (i-1) and (i-2) as R ¹³ to R can be mentioned. ¹⁵ and R ¹⁷ to R ¹⁹ are the same as those exemplified as the monovalent hydrocarbon group having 1 to 20 carbon atoms.

Examples of the substituents of the groups represented by R ³¹ , R ³² and R ³³ include those represented by R ^4a , R ^5a , R ^6a , R ^9a and R ^10a in the above-mentioned formulas (1) and (2). The represented monovalent substituent and the group exemplified are the same groups. k1 is preferably an integer of 0 to 2, more preferably 0 or 1, still more preferably 0. t1 is preferably 0.

In the above formula (5), as R ³⁴ and R ³⁵ , preferably substituted or unsubstituted monovalent hydrocarbon groups having 1 to 20 carbon atoms, -OR ^k , -COOR ^k , -O-CO-R ^k , -OR ^kk -COOR ^k or -R ^kk -CO-R ^k . R ^k is a monovalent hydrocarbon group having 1 to 10 carbon atoms. R ^kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms. Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ³⁴ and R ³⁵ include the same groups as R ¹³ to R ¹⁵ and R ¹⁷ to R in the above-mentioned formulas (i-1) and (i-2), for example. The monovalent hydrocarbon group having 1 to 20 carbon atoms represented by ¹⁹ is the same as the group exemplified. In addition, in R ³⁴ and R ³⁵ , the substituents which are exemplified as the substituents which the groups represented by the above R ³¹ , R ³² and R ³³ are exemplified as the substituent which substitutes the hydrogen atom which the hydrocarbon group has. the same base. Examples of the divalent organic group represented by R ³⁶ include a group obtained by removing one hydrogen atom from the monovalent organic groups having 1 to 20 carbon atoms exemplified as R ³⁴ and R ³⁵ . k3 is preferably an integer of 0 to 2, more preferably 0 or 1, still more preferably 0. t2 is preferably 0. t3 is preferably 2 or 3, more preferably 2.

In the above formula (6), R ³⁷ and R ³⁸ are preferably substituted or unsubstituted monovalent hydrocarbon groups having 1 to 20 carbon atoms, -OSO ₂ -R ^k , -SO ₂ -R ^k , - OR ^k , -COOR ^k , -O-CO-R ^k , -OR ^kk -COOR ^k , -R ^kk -CO-R ^k , -SR ^k , or a ring structure formed by combining two or more of these groups with each other . In addition, R ^k and R ^kk have the same meanings as R ^k and R ^kk which the group represented by the above-mentioned R ³⁴ and R ³⁵ has. As the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ³⁷ and R ³⁸ , for example, the same groups as R ¹³ to R ¹⁵ and R ¹⁷ to R in the above-mentioned formulas (i-1) and (i-2) can be mentioned. The monovalent hydrocarbon group having 1 to 20 carbon atoms represented by ¹⁹ is the same as the group exemplified. In addition, in R ³⁷ and R ³⁸ , the substituents exemplified as the substituents of the groups represented by the above R ³¹ , R ³² and R ³³ are exemplified as the substituent which substitutes the hydrogen atom which the hydrocarbon group has. the same base. As k4 and k5, an integer of 0-2 is preferable, 0 or 1 is more preferable, and 0 is still more preferable.

Among these, other organic cations are preferably the radioactive onium cation represented by the formula (4) and the radioactive onium cation represented by the formula (6), and more preferably have a triaryl perionium cation structure or A radiosensitive onium cation of the diaryliodonium cationic structure. Specifically, from the viewpoint of making the lithography characteristics of the present composition good, it is particularly preferable that the other organic cations are radiation-sensitive onium cations satisfying a1+a2+a3≦1 in the formula (1), and A radiation-sensitive onium cation satisfying a7+a8≦1 in the formula (2) (wherein, “*” in the formulae (1) and (2) represents a bond with a hydrogen atom).

（式（7）中，n1為0～10的整數；n2為0～10的整數；n3為1～10的整數；n1+n2+n3為1以上且30以下；於n1為2以上的情況下，多個R ^p2相同或不同；於n2為2以上的情況下，多個R ^p3相同或不同，多個R ^p4相同或不同；於n3為2以上的情況下，多個R ^p5相同或不同，多個R ^p6相同或不同；R ^p1為包含環員數5以上的環結構的一價基；R ^p2為二價連結基；R ^p3及R ^p4分別獨立地為氫原子、氟基、碳數1～20的一價烴基、或碳數1～20的一價氟化烴基；R ^p5及R ^p6分別獨立地為氫原子、氟基或碳數1～20的一價氟化烴基；其中，於n3為1的情況下，R ^p5及R ^p6不會均為氫原子，於n3為2以上的情況下，多個R ^p5及R ^p6不會全部為氫原子） ·Organic anion In the onium salt [LB1] and the onium salt [LB2], the organic anion is not particularly limited. As an organic anion, the organic anion which has a sulfonate anion structure, an imide anion structure, or a methide anion structure is mentioned, for example. Among these, the organic anion is preferably an organic anion having a sulfonate anion structure. Specifically, as the organic anion in the (B) acid generator, an organic anion represented by the following formula (7) can be preferably used. [hua 20]

(In formula (7), n1 is an integer of 0 to 10; n2 is an integer of 0 to 10; n3 is an integer of 1 to 10; n1+n2+n3 is 1 or more and 30 or less; when n1 is 2 or more When n2 is 2 or more, a plurality of R ^p3 are the same or different, and a plurality of R ^{p4 are} the same or different; when n3 is 2 or more, a plurality of R ^p5 are the same or different Different, a plurality of R ^p6 are the same or different; R ^p1 is a monovalent group containing a ring structure with more than 5 ring members; R ^p2 is a divalent linking group; R ^p3 and R ^p4 are independently hydrogen atom, fluorine group, A monovalent hydrocarbon group with 1 to 20 carbon atoms, or a monovalent fluorinated hydrocarbon group with 1 to 20 carbon atoms; R ^p5 and R ^p6 are independently a hydrogen atom, a fluorine group or a monovalent fluorinated hydrocarbon group with 1 to 20 carbon atoms; However, when n3 is 1, both R ^p5 and R ^p6 are not hydrogen atoms, and when n3 is 2 or more, a plurality of R ^p5 and R ^p6 are not all hydrogen atoms)

In the above formula (7), examples of the monovalent group including a ring structure having 5 or more ring members represented by R ^p1 include: a monovalent group including an alicyclic structure having 5 or more ring members, A monovalent group containing an aliphatic heterocyclic structure having 5 or more ring members, a monovalent group containing an aromatic ring structure having 5 or more ring members, a monovalent group containing an aromatic heterocyclic structure having 5 or more ring members, and the like.

Examples of the alicyclic structure having 5 or more ring members include a cyclopentane structure, a cyclohexane structure, a cycloheptane structure, a cyclooctane structure, a cyclononane structure, a cyclodecane structure, and a cyclododecane structure. Monocyclic cycloalkane structure such as cyclopentene structure, cyclohexene structure, cycloheptene structure, cyclooctene structure, cyclodecene structure and other monocyclic cycloalkene structures; norbornane structure, adamantane structure, tricyclodecene structure Polycyclic cycloalkane structures such as alkane structure and tetracyclododecane structure; polycyclic cycloalkene structures such as norbornene structure and tricyclodecene structure, etc.

Examples of the aliphatic heterocyclic structure having 5 or more ring members include lactone structures such as a caprolactone structure and a norbornane lactone structure; Sultone structures such as ester structures; heterocyclic structures containing oxygen atoms such as oxane structures, oxanorbornane structures, and cyclic acetal structures; azacyclohexane structures, diazabicyclooctane structures and other heterocyclic structures containing nitrogen atoms; heterocyclic structures containing sulfur atoms such as thiacyclohexane structure, thianorbornane structure, etc.

As an aromatic ring structure with 5 or more ring members, a benzene structure, a naphthalene structure, a phenanthrene structure, an anthracene structure etc. are mentioned, for example. Examples of aromatic heterocyclic structures having 5 or more ring members include oxygen-containing heterocyclic structures such as furan structures, pyran structures, and benzopyran structures; nitrogen-containing structures such as pyridine structures, pyrimidine structures, and indole structures. Heterocyclic structure of atoms, etc.

In addition, a part or all of the hydrogen atoms which the ring structure of R ^p1 has may be substituted with a substituent. Examples of the substituent include a fluoro group, a chloro group, a bromo group, an iodo group, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an alkoxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, and an acyl group. , oxyalkyl, etc.

Among the above, the monovalent group represented by R ^p1 is preferably a group having an aromatic ring structure with 5 or more ring members, and particularly preferably a group having a benzene structure. In addition, the monovalent group represented by R ^p1 is preferably a group having an aromatic ring structure substituted with a halogen group, more preferably a group having an aromatic ring structure substituted with one or more iodo groups. In such a case, in the monovalent group represented by R ^p1 , the number of iodine groups bonded to the aromatic ring is more preferably two or more, and particularly preferably three or more.

Examples of the divalent linking group represented by R ^p2 include a carbonyl group, an ether group, a carbonyloxy group, a thioether group, a thiocarbonyl group, a sulfonyl group, a divalent hydrocarbon group, and the like. Among these, carbonyloxy, sulfonyl, alkanediyl or cycloalkanediyl is preferred, carbonyloxy or cycloalkanediyl is more preferred, carbonyloxy or norbornanediyl is further preferred, and Preferred is carbonyloxy.

The monovalent hydrocarbon group having 1 to 20 carbon atoms represented by R ^p3 and R ^p4 includes, for example, an alkyl group having 1 to 20 carbon atoms. The monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ^p3 and R ^p4 includes, for example, a fluorinated alkyl group having 1 to 20 carbon atoms. As R ^p3 and R ^p4 , a hydrogen atom, a fluorine group, or a fluoroalkyl group is preferred, a fluorine group or a perfluoroalkyl group is more preferred, and a fluorine group or a trifluoromethyl group is still more preferred.

The monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by R ^p5 and R ^p6 includes, for example, a fluoroalkyl group having 1 to 20 carbon atoms. As R ^p5 and R ^p6 , a fluoro group or a fluoroalkyl group is preferable, a fluoro group or a perfluoroalkyl group is more preferable, a fluoro group or a trifluoromethyl group is further preferable, and a fluoro group is particularly preferable. When n3 is 1, it is preferable that both R ^p5 and R ^p6 are fluoro groups, or that R ^p5 is fluoro groups and R ^p6 is trifluoromethyl group.

n1 is preferably 0 to 5, more preferably 0 to 3, further preferably 0 to 2, particularly preferably 0 or 1. n2 is preferably 0 to 5, more preferably 0 to 2, further preferably 0 or 1, particularly preferably 0. n3 is preferably 1-5, more preferably 1-3, still more preferably 1 or 2. By making n3 into the said range, the intensity|strength of the acid generate|occur|produced from the (B) acid generator can be improved, and as a result, the defect suppression property, LWR performance, and sensitivity of this composition can be improved further. n1+n2+n3 is preferably 2 or more. In addition, n1+n2+n3 is preferably 10 or less, more preferably 5 or less.

（式（7A）中，R ^p7為一價取代基；n4為0～5的整數；「*」表示鍵結鍵） In the (B) acid generator, the organic anion preferably has a benzalyloxy group-containing perium anion structure. Specifically, "R ^p1 -(R ^p2 ) _n1 -" in the formula (7) is preferably a structure represented by the following formula (7A). In addition, in the following formula (7A), as a specific example of the monovalent substituent represented by R ^p7 , the same examples as the examples of the substituent which the ring structure represented by R ^p1 of the above formula (7) may have are mentioned. the base. [Chemical 21]

(In formula (7A), R ^p7 is a monovalent substituent; n4 is an integer of 0 to 5; "*" represents a bond)

[化23]

[化24]

As a specific example of the organic anion which the (B) acid generator has, the organic anion etc. which are represented by the following formula are mentioned, for example. However, the organic anion which the (B) acid generator has is not limited to the following structures. [Chemical 22]

[Chemical 23]

[Chemical 24]

The onium salt [LB1] is preferably at least one selected from the group consisting of compounds comprising a radioactive onium cation having a partial structure represented by the formula (1) and an organic anion, and a compound comprising A compound of a partially structured radioactive onium cation and an organic anion represented by the formula (2). Moreover, as a specific example of the onium salt [LB2], the compound containing the organic cation and the organic anion represented by the said formula (4), and the compound containing the organic cation and the organic anion represented by the said formula (5) are mentioned. , and a compound containing an organic cation and an organic anion represented by the formula (6).

When the (B) acid generator is a low molecular weight compound, the molecular weight of the (B) acid generator is preferably 1000 or less, more preferably 900 or less, still more preferably 800 or less, and still more preferably 600 or less. Moreover, when the (B) acid generator is a low molecular weight compound, the molecular weight of the (B) acid generator is, for example, 100 or more, and more preferably 150 or more.

When the (B) acid generator is a polymer, the polymer (hereinafter, also referred to as "polymer (PB)") is a polymer having the structural unit (III). Specific examples of the polymer (PB) include the following polymer [PB1] and polymer [PB2]. [PB1] Polymer: a polymer derived from a monomer including a radiosensitive onium cation having two or more substituents β and an organic anion, and any one of the radiosensitive onium cation and the organic anion includes a group participating in polymerization the monomeric structural unit. [PB2] Polymer: a monomer having a structural unit derived from a monomer including other organic cations and organic anions, and any one of the other organic cations and organic anions includes a group participating in polymerization.

As a specific example of the structural unit (III) which a polymer (PB) has, the structural unit etc. each represented by the said formula (iii-1a) - (iii-9a) are mentioned.

The polymer (PB) may further have a structural unit different from the structural unit (III). As this structural unit, the structural unit etc. exemplified as another structural unit in the description of (A) polymer are mentioned, for example. The polymer (PB) can be synthesized by the same method as the method described above as the synthesis method of the (A) polymer.

The weight average molecular weight (Mw) of the polymer (PB) in terms of polystyrene obtained by GPC is preferably 1,000 or more, more preferably 2,000 or more, still more preferably 3,000 or more, and particularly preferably 5,000 or more. Moreover, Mw of a polymer (PB) becomes like this. Preferably it is 50,000 or less, More preferably, it is 30,000 or less, More preferably, it is 20,000 or less, Especially preferably, it is 10,000 or less. In addition, the ratio (Mw/Mn) of Mw of the polymer (PB) to the number average molecular weight (Mn) in terms of polystyrene obtained by GPC is preferably 5 or less, more preferably 3 or less, and still more preferably 2 or less, particularly preferably 1.7 or less. Moreover, Mw/Mn of a polymer (PB) is 1 or more normally, Preferably it is 1.3 or more.

As the acid generator (B) in the present composition, it is preferable to use the low-molecular-weight compounds described above (ie, onium salt [LB1] and onium salt [LB2]), and it is more preferable to contain onium salt [LB1].

The content ratio of the (B) acid generator in the present composition is preferably 1 mass % or more, more preferably 2 mass % or more, and still more preferably 3 mass % or more with respect to 100 mass parts of the (A) polymer. Moreover, 30 mass % or less is preferable with respect to 100 mass parts of (A) polymers, and, as for the content rate of (B) acid generator, 20 mass % or less is more preferable, and 15 mass % or less is more preferable. By making the content ratio of the (B) acid generator into the above-mentioned range, the defect suppression property, LWR performance, and sensitivity of the present composition can be further improved, which is suitable in this respect. As the (B) acid generator, one type may be used alone, or two or more types may be used in combination.

<(C) Acid diffusion control agent> (C) The acid diffusion control agent is formulated into the present composition for the purpose of preventing the acid generated from the (B) acid generator by exposure to diffuse in the resist film. Inhibition, thereby inhibiting the chemical reaction caused by the acid in the non-exposed areas. By blending the (C) acid diffusion control agent in the present composition, the lithography characteristics of the present composition can be further improved, which is suitable in this respect. Furthermore, the change of the line width of the resist pattern due to the fluctuation of the standing time from exposure to development treatment can be suppressed, and a radiation-sensitive composition excellent in process stability can be obtained.

(C) As an acid diffusion control agent, a nitrogen-containing compound or a photodegradable base is mentioned, for example. As the photodegradable base, a compound that generates an acid weaker than the acid generated by the (B) acid generator by exposure to light can be used. Specific examples of the photodegradable base include nitrogen-containing compounds, compounds that generate weak acids (preferably carboxylic acids), sulfonic acids, or sulfonamides by exposure to light. In addition, the magnitude of the acidity can be evaluated by the acid dissociation constant (pKa). The acid dissociation constant of the acid generated by the photodegradable alkali is usually -3 or more, preferably -1≦pKa≦7, more preferably 0≦pKa≦5. (C) The acid diffusion control agent is preferably a low molecular compound.

Furthermore, in the aspect in which the present composition contains the (B) acid generator and the (C) acid diffusion control agent, when a photodegradable base is contained as the (C) acid diffusion control agent, the (B) acid generation The agent corresponds to the "first acid generator", and the photodegradable base corresponds to the "second acid generator".

（式（8）中，R ⁴¹、R ⁴²及R ⁴³分別獨立地為氫原子、經取代或未經取代的烷基、經取代或未經取代的環烷基、經取代或未經取代的芳基、或者經取代或未經取代的芳烷基） Nitrogen-containing compounds Examples of nitrogen-containing compounds include compounds represented by the following formula (8) (hereinafter, also referred to as “nitrogen-containing compounds (8A)”), compounds having two nitrogen atoms (hereinafter, also referred to as “nitrogen-containing compounds (8A)”). referred to as "nitrogen-containing compound (8B)"), compound having three nitrogen atoms (hereinafter, also referred to as "nitrogen-containing compound (8C)"), amide group-containing compound, urea compound, nitrogen-containing heterocyclic compound , Nitrogen-containing compounds with acid dissociable groups, etc. [Chemical 25]

(In formula (8), R ⁴¹ , R ⁴² and R ⁴³ are each independently a hydrogen atom, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted aralkyl)

Specific examples of the nitrogen-containing compound include, for example, the nitrogen-containing compound (8A): monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; triethylamine, tri-n-butylamine, etc. Trialkylamines such as amylamine; aromatic amines such as aniline and 2,6-diisopropylaniline, etc. As a nitrogen-containing compound (8B), ethylenediamine, N,N,N',N'- tetramethylethylenediamine etc. are mentioned, for example. Examples of the nitrogen-containing compound (8C) include polyamine compounds such as polyethyleneimine and polyallylamine; and polymers such as dimethylaminoethylacrylamide.

Examples of the amide group-containing compound include carboxamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N - Dimethylacetamide, propionamide, benzylamide, pyrrolidone, N-methylpyrrolidone, etc. As a urea compound, urea, methyl urea, 1, 1- dimethyl urea, 1, 3- dimethyl urea, 1, 1, 3, 3- tetramethyl urea, 1, 3- di- Phenyl urea, tributyl thiourea, etc. Examples of nitrogen-containing heterocyclic compounds include pyridines such as pyridine and 2-picoline; morpholines such as N-propylmorpholine and N-(undecan-1-ylcarbonyloxyethyl)morpholine class; pyrazine, pyrazole, etc.

Examples of the nitrogen-containing compound having an acid dissociable group include N-tert-butoxycarbonylpiperidine, N-tert-butoxycarbonylimidazole, N-tert-butoxycarbonylbenzimidazole, N-tert-butoxycarbonylbenzimidazole, Third-butoxycarbonyl-2-phenylbenzimidazole, N-(third-butoxycarbonyl)di-n-octylamine, N-(third-butoxycarbonyl)diethanolamine, N-(third-butoxycarbonyl)diethanolamine Butoxycarbonyl) dicyclohexylamine, N-(tertiary butoxycarbonyl) diphenylamine, N-tertiary butoxycarbonyl-4-hydroxypiperidine, N-tertiary pentyloxycarbonyl- 4-Hydroxypiperidine etc.

Among them, the nitrogen-containing compound as the (C) acid diffusion control agent is preferably at least one selected from the group consisting of nitrogen-containing compounds (8A) and nitrogen-containing heterocyclic compounds, more preferably selected from trialkylamines At least one selected from the group consisting of tri-n-pentylamine, 2,6-diisopropylaniline and N-(undecane-1- at least one of the group consisting of carbonylcarbonyloxyethyl)morpholine.

·Photodegradable base The photodegradable base is preferably a compound which generates an acid by irradiation with radiation, and which does not substantially dissociate the acid-dissociable group in the composition when the acid is heated at a temperature of 110° C. for 1 minute. The photodegradable base is typically a compound that does not or hardly causes a dissociation reaction of an acid dissociable group under the conditions of use by an acid generated by exposure.

（式（9）中，E ^-為R ⁵¹-COO ^-、R ⁵²-SO ₂-N ^--R ⁵¹或R ⁵¹-SO ₃ ^-所表示的有機陰離子；R ⁵¹及R ⁵²分別獨立地為碳數1～30的一價有機基；其中，於E ^-為R ⁵¹-SO ₃ ^-所表示的有機陰離子的情況下，在SO ₃ ^-所鍵結的碳原子上並未鍵結氟原子；G ⁺為感放射線性鎓陽離子） As the photodegradable base, an onium salt of a carboxylic acid, a sulfonic acid, or a sulfonamide by irradiation with radiation can be preferably used. Preferable specific examples of the photodegradable base include onium salt compounds represented by the following formula (9). [Chemical 26]

(In formula (9), E ^- is an organic anion represented by R ⁵¹ -COO ^- , R ⁵² -SO ₂ -N ^- -R ⁵¹ or R ⁵¹ -SO ₃ ^- ; R ⁵¹ and R ⁵² are each independently carbon A monovalent organic group of numbers 1 to 30; wherein, when E ^- is an organic anion represented by R ⁵¹ -SO ₃ ^- , a fluorine atom is not bound to the carbon atom to which SO ₃ ^- is bound; G ⁺ is a radioactive onium cation)

In the above formula (9), examples of the monovalent organic group having 1 to 30 carbon atoms represented by R ⁵¹ include a monovalent hydrocarbon group having 1 to 30 carbon atoms, a carbon-carbon bond between the hydrocarbon group, or a bonding bond. A monovalent group γ having a carbon number of 1 to 30 containing a divalent heteroatom-containing group at the side end, and at least one hydrogen atom contained in a hydrocarbon group or a monovalent group γ is substituted with a monovalent heteroatom-containing group. The one-price basis, etc. Specific examples of these include the same groups as the groups exemplified as the monovalent organic groups represented by R ³¹ , R ³² and R ³³ in the above formula (4). Among them, the monovalent organic group having 1 to 30 carbon atoms represented by R ⁵¹ is preferably a substituted or unsubstituted monovalent group having an aromatic ring. The group represented by R ⁵¹ may have a partial structure represented by the above formula (7A).

Examples of the monovalent organic group having 1 to 30 carbon atoms represented by R ⁵² include a substituted or unsubstituted alkyl group and a substituted or unsubstituted cycloalkyl group. A fluorine group etc. are mentioned as a substituent in a substituted alkyl group. As a substituent in a substituted cycloalkyl group, a C1-C10 alkyl group, a fluorine group, an iodine group, etc. are mentioned.

The radioactive onium cation represented by G ⁺ is preferably an organic cation represented by the formula (Y-1) or the formula (Y-2). The radiosensitive onium cation represented by G ⁺ may have a specific cation structure [X], or may be other organic cations. Specific examples of the photodegradable base include the following onium salt [C1] and onium salt [C2], for example. [C1] Onium salt: a radioactive onium cation having two or more substituents β and an organic anion are included. [C2] Onium salt: Contains a radiosensitive onium cation (other organic cation) with only one substituent β or no substituent β and an organic anion.

In the onium salt [C1], examples of the radiosensitive onium cation having two or more substituents β include a radiosensitive onium cation having a partial structure represented by the formula (1), and a radiosensitive onium cation having the above-mentioned formula (1). A radioactive onium cation having a partial structure represented by the formula (2). As another organic cation, the onium cation represented by the said formula (4), the onium cation represented by the said formula (5), and the onium cation represented by the said formula (6), etc. are mentioned.

[化28]

The organic anion which the photodegradable base has preferably has a carboxylate anion structure or a sulfonate anion structure. As a specific example of this organic anion, the organic anion etc. which are represented, for example by the following formula are mentioned. However, the organic anion which the photodegradable base has is not limited to the following structures. [Chemical 27]

[Chemical 28]

Specific examples of the onium salt [C1] include, for example, a compound comprising a radiosensitive onium cation having the partial structure represented by the formula (1) and a carboxylate anion or a sulfonate anion, a compound having the above-mentioned A compound of a partial structure of the radiosensitive onium cation represented by the formula (2) and a carboxylate anion or a sulfonate anion, or the like. In addition, specific examples of the onium salt [C2] include a compound containing the organic cation represented by the formula (4) and a carboxylate anion or a sulfonate anion, a compound containing the organic cation represented by the formula (5) and a carboxylate anion or a sulfonate anion. A compound of an organic cation and a carboxylate anion or a sulfonate anion, a compound containing the organic cation represented by the formula (6) and a carboxylate anion or a sulfonate anion, and the like.

(C) The molecular weight of the acid diffusion control agent is preferably 1000 or less, more preferably 900 or less, still more preferably 800 or less, and still more preferably 600 or less. Moreover, the molecular weight of the (C) acid diffusion control agent is, for example, 100 or more, or preferably 150 or more.

When the present composition contains the (C) acid diffusion control agent, the content ratio of the (C) acid diffusion control agent in the present composition is preferably 0.1% by mass or more relative to 100 parts by mass of the (A) polymer, More preferably, it is 1 mass % or more, and still more preferably 3 mass % or more. Moreover, 20 mass % or less is preferable with respect to 100 mass parts of (A) polymers, and, as for the content rate of (C) acid diffusion control agent, it is more preferable that it is 15 mass % or less, and it is still more preferable that it is 10 mass % or less. By setting the content ratio of the (C) acid diffusion control agent to the above-mentioned range, the LWR performance of the present composition can be further improved, which is suitable in this respect. As the (C) acid diffusion control agent, one type may be used alone, or two or more types may be used in combination.

The ratio of the acid generating compound contained in the composition (that is, the total ratio of the (B) acid generator and the (C) acid diffusion control agent) relative to the total amount of the solid content contained in the composition is higher than that of the composition. Preferably it is 1 mass % or more, More preferably, it is 2 mass % or more, More preferably, it is 5 mass % or more, More preferably, it is 10 mass % or more. In addition, the ratio of the acid generating compound is preferably 20% by mass or less, more preferably 15% by mass or less, more preferably 10% by mass or less, and still more preferably 10% by mass or less with respect to the total amount of the solid content contained in the composition. 8 mass % or less. By setting the content ratio of the acid generating compound to the above-mentioned range, the lithography characteristics such as LWR performance and CDU performance of the present composition can be improved, which is suitable in this respect.

In the present composition, the ratio of the specific cation structure [X] in the radiosensitive onium cation possessed by the acid generating compound is preferably 10 mol % or more, more preferably 20 mol % or more, and further preferably 50 mol % ear % or more, more preferably 70 mol % or more. By setting the ratio of the specific cation structure [X] to the radiosensitive onium cation possessed by the acid generating compound in the above range, the effects of improving the sensitivity, CDU performance and development residue suppression of the composition can be sufficiently obtained. Appropriately.

In the present composition, the content ratio of the polymer [P] is preferably 5% by mass or more, more preferably 10% by mass or more, with respect to the total amount (100% by mass) of the solid content contained in the present composition, and further Preferably it is 30 mass % or more, More preferably, it is 50 mass % or more, Especially preferably, it is 65 mass % or more. By setting the ratio of the polymer [P] to the total amount of the solid content contained in the composition within the above-mentioned range, the sensitivity and CDU performance of the composition can be made good, and furthermore, the development residue suppression can be sufficiently obtained. It is suitable in this respect to improve the effect. The polymer [P] is preferably a polymer having a structural unit (I) in terms of its high effect of reducing development residues, and in terms of further enhancing the effect of improving the sensitivity of the composition, it is more Preferably it is a polymer which has a structural unit (I) and a structural unit (II).

<(D) Solvent> The (D) solvent is not particularly limited as long as it is a solvent capable of dissolving or dispersing the (A) polymer, the (B) acid generator, and the (C) acid diffusion control agent contained if necessary. As (D) solvent, alcohols, ethers, ketones, amides, esters, hydrocarbons, etc. are mentioned, for example.

Examples of alcohols include aliphatic monoalcohols having 1 to 18 carbon atoms such as 4-methyl-2-pentanol and n-hexanol; alicyclic monoalcohols having 3 to 18 carbon atoms such as cyclohexanol; Polyols with 2 to 18 carbon atoms such as 2-propylene glycol; partial ethers of polyols with 3 to 19 carbon atoms such as propylene glycol monomethyl ether, etc. Examples of ethers include dialkyl ethers such as diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, and diheptyl ether; tetrahydrofuran, Cyclic ethers such as tetrahydropyran; ethers containing aromatic rings such as diphenyl ether, anisole, etc.

Examples of ketones include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-isobutyl ketone, 2-heptanone, Chain ketones such as ethyl-n-butyl ketone, methyl-n-hexyl ketone, di-isobutyl ketone, trimethylnonanone; cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methyl Cyclic ketones such as cyclohexanone; 2,4-pentanedione, acetone acetone, acetophenone, diacetone alcohol, etc. Examples of amides include cyclic amides such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone; N-methylformamide, N,N-dimethylformamide, and the like. Acetamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, N-methylpropionamide and other chain amides, etc. .

Examples of esters include: monocarboxylic acid esters such as n-butyl acetate and ethyl lactate; polyol carboxylic acid esters such as propylene glycol acetate; polyhydric alcohol partial ether carboxylic acid esters such as propylene glycol monomethyl ether acetate; oxalic acid Polycarboxylic acid diesters such as diethyl ester; carbonates such as dimethyl carbonate and diethyl carbonate; cyclic esters such as γ-butyrolactone and the like. Examples of hydrocarbons include aliphatic hydrocarbons having 5 to 12 carbon atoms such as n-pentane and n-hexane, and aromatic hydrocarbons having 6 to 16 carbon atoms such as toluene and xylene.

As the solvent (D), among these, it is preferable to contain at least one selected from the group consisting of esters and ketones, and it is more preferable to contain at least one selected from the group consisting of polyhydric alcohol partial ether carboxylates and cyclic ketones At least one of the formed group, more preferably, includes at least one of propylene glycol monomethyl ether acetate, ethyl lactate, and cyclohexanone. As the (D) solvent, one kind or two or more kinds can be used.

<(E) High fluorine-containing polymer> (E) The high fluorine-containing polymer (hereinafter, also simply referred to as "(E) polymer") is a polymer having a higher mass content of fluorine atoms than that of the (A) polymer. (E) The polymer is contained in the present composition as, for example, a water-repellent additive.

The fluorine atom content of the polymer (E) is not particularly limited as long as it is larger than that of the polymer (A), but is preferably 1 mass % or more, more preferably 2 mass % or more, still more preferably 4 mass % or more, particularly preferably It is 7 mass % or more. In addition, the fluorine atom content of the polymer (E) is preferably 60 mass % or less, more preferably 40 mass % or less, and still more preferably 30 mass % or less. The structure of the polymer can be obtained by ¹³ C-Nuclear Magnetic Resonance (NMR) spectrometry or the like, and the fluorine atom content (% by mass) of the polymer can be calculated from the structure.

As a structural unit which (E) polymer has, the following structural unit (Ea), structural unit (Eb), etc. are mentioned, for example. (E) The polymer may have one or more of the structural unit (Ea) and the structural unit (Eb), respectively.

（式（11a）中，R ^C為氫原子、氟基、甲基或三氟甲基；G為單鍵、氧原子、硫原子、-CO-O-、-SO ₂-O-NH-、-CO-NH-或者-O-CO-NH-；R ^E為碳數1～6的一價氟化鏈狀烴基或碳數4～20的一價氟化脂環式烴基） [Structural unit (Ea)] The structural unit (Ea) is a structural unit represented by the following formula (11a). The (E) polymer can adjust the fluorine atom content by having the structural unit (Ea). [Chemical 29]

(In formula (11a), R ^C is a hydrogen atom, a fluorine group, a methyl group or a trifluoromethyl group; G is a single bond, an oxygen atom, a sulfur atom, -CO-O-, -SO ₂ -O-NH-, -CO-NH- or -O-CO-NH-; R ^E is a monovalent fluorinated chain hydrocarbon group with 1 to 6 carbon atoms or a monovalent fluorinated alicyclic hydrocarbon group with 4 to 20 carbon atoms)

Examples of the monovalent fluorinated chain hydrocarbon group having 1 to 6 carbon atoms represented by R ^E include trifluoromethyl, 2,2,2-trifluoroethyl, perfluoroethyl, 2,2,3 ,3,3-pentafluoropropyl, 1,1,1,3,3,3-hexafluoropropyl, perfluoron-propyl, perfluoroisopropyl, perfluoron-butyl, perfluoroisobutyl , perfluoro tert-butyl, 2,2,3,3,4,4,5,5-octafluoropentyl, perfluorohexyl, etc.

Examples of the monovalent fluorinated alicyclic hydrocarbon group having 4 to 20 carbon atoms represented by R ^E include monofluorocyclopentyl, difluorocyclopentyl, perfluorocyclopentyl, monofluorocyclohexyl, and difluoro Cyclohexyl, perfluorocyclohexylmethyl, fluoronorbornyl, fluoroadamantyl, fluorobornyl, fluoroisobornyl, fluorotricyclodecyl, fluorotetracyclodecyl and the like.

As a monomer which provides a structural unit (Ea), the (meth)acrylate which has a fluorinated chain hydrocarbon group, the (meth)acrylate which has a fluorinated alicyclic hydrocarbon group, etc. are mentioned, for example. Specific examples of these include linear partially fluorinated alkyl groups such as 2,2,2-trifluoroethyl (meth)acrylate as the (meth)acrylate having a fluorinated chain hydrocarbon group, for example. (meth)acrylates; branched partially fluorinated alkyl (meth)acrylates such as 1,1,1,3,3,3-hexafluoroisopropyl (meth)acrylates; perfluoroethyl (meth)acrylates Linear perfluoroalkyl (meth)acrylates such as meth)acrylates; branched perfluoroalkyl (meth)acrylates such as perfluoroisopropyl (meth)acrylates, and the like.

Examples of the (meth)acrylate having a fluorinated alicyclic hydrocarbon group include perfluorocyclohexylmethyl (meth)acrylate, monofluorocyclopentyl (meth)acrylate, perfluorocyclopentyl Monocyclic (meth)acrylates having fluorinated alicyclic saturated hydrocarbon groups such as (meth)acrylates; polycyclic (meth)acrylates having fluorinated alicyclic saturated hydrocarbon groups such as fluoronorbornyl (meth)acrylates meth)acrylate, etc.

In the case where the (E) polymer has a structural unit (Ea), the content of the structural unit (Ea) is preferably 5 mol % or more, more preferably 10 mol % or more with respect to all the structural units constituting the (E) polymer. mol% or more, more preferably 20 mol% or more.

（式（11b）中，R ^F為氫原子、氟基、甲基或三氟甲基；R ⁵⁹為碳數1～20的（s+1）價的烴基，或於該烴基的R ⁶⁰側的末端鍵結氧原子、硫原子、-NR'-、羰基、-CO-O-或-CO-NH-而成的基；R'為氫原子或一價有機基；R ⁶⁰為單鍵、碳數1～10的二價鏈狀烴基或碳數4～20的二價脂環式烴基；X ¹²為碳數1～20的二價氟化鏈狀烴基；A ¹¹為氧原子、-NR''-、-CO-O-*或-SO ₂-O-*；R"為氫原子或一價有機基；*表示與R ⁶¹鍵結的鍵結部位；R ⁶¹為氫原子或一價有機基；s為1～3的整數；其中，於s為2或3的情況下，多個R ⁶⁰、X ¹²、A ¹¹及R ⁶¹分別相同或不同） [Structural unit (Eb)] The structural unit (Eb) is a structural unit represented by the following formula (11b). (E) Since the polymer has the structural unit (Eb), the hydrophobicity is improved, so that the dynamic contact angle of the surface of the resist film formed from the present composition can be further improved. [Chemical 30]

(In formula (11b), R ^F is a hydrogen atom, a fluorine group, a methyl group or a trifluoromethyl group; R ⁵⁹ is a (s+1)-valent hydrocarbon group with 1 to 20 carbon atoms, or on the R ⁶⁰ side of the hydrocarbon group The end of the group is bound with oxygen atom, sulfur atom, -NR'-, carbonyl, -CO-O- or -CO-NH-; R' is hydrogen atom or monovalent organic group; R ⁶⁰ is a single bond, A divalent chain hydrocarbon group with 1 to 10 carbon atoms or a bivalent alicyclic hydrocarbon group with 4 to 20 carbon atoms; X ¹² is a divalent fluorinated chain hydrocarbon group with a carbon number of 1 to 20; A ¹¹ is an oxygen atom, -NR ''-, -CO-O-* or -SO ₂ -O-*; R" is a hydrogen atom or a monovalent organic group; * represents a bonding site with R ⁶¹ ; R ⁶¹ is a hydrogen atom or a monovalent organic group organic group; s is an integer of 1 to 3; wherein, when s is 2 or 3, a plurality of R ⁶⁰ , X ¹² , A ¹¹ and R ⁶¹ are respectively the same or different)

When R ⁶¹ is a hydrogen atom, the solubility of the (E) polymer with respect to an alkaline developer can be improved, which is preferable in this respect. Examples of the monovalent organic group represented by R ⁶¹ include an acid dissociable group, an alkali dissociable group, a hydrocarbon group having 1 to 30 carbon atoms which may have a substituent, and the like.

When the (E) polymer has a structural unit (Eb), the content ratio of the structural unit (Eb) is preferably 5 mol % or more, more preferably 10 mol % or more with respect to all the structural units constituting the (E) polymer. mol% or more, more preferably 20 mol% or more.

(E) The polymer may contain, in addition to the structural unit (Ea) and the structural unit (Eb), a structural unit ( Hereinafter, also referred to as "structural unit (Ec)"). As a structural unit (Ec), (A) the structural unit (I) which a polymer may have can be mentioned. Furthermore, the (E) polymer does not have the structural unit (III).

When the (E) polymer has a structural unit (Ec), the content of the structural unit (Ec) is preferably 90 mol % or less, more preferably 80 mol % or less, with respect to all the structural units constituting the (E) polymer. mol % or less, more preferably 70 mol % or less.

(E) Mw of the polymer obtained by GPC is preferably 1,000 or more, more preferably 3,000 or more, and still more preferably 4,000 or more. Moreover, Mw of (E) polymer becomes like this. Preferably it is 50,000 or less, More preferably, it is 30,000 or less, More preferably, it is 20,000 or less. (E) The molecular weight distribution (Mw/Mn) represented by the ratio of Mn to Mw obtained by GPC of the polymer is usually 1 or more, preferably 1.2 or more. In addition, Mw/Mn is preferably 5 or less, more preferably 3 or less.

When the present composition contains the (E) polymer, the content of the (E) polymer in the present composition is preferably 0.1 part by mass or more, more preferably 1 part by mass relative to 100 parts by mass of the (A) polymer part by mass or more, more preferably 2 parts by mass or more. In addition, the content of the (E) polymer is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and still more preferably 7 parts by mass or less, relative to 100 parts by mass of the (A) polymer. In addition, this composition may contain a single type of (E) polymer, or may contain two or more types in combination.

<Other optional ingredients> The present composition may further contain components (the following , also known as "other arbitrary components"). Examples of other optional components include surfactants, alicyclic skeleton-containing compounds (for example, 1-adamantanecarboxylic acid, 2-adamantanone, tert-butyl deoxycholate, etc.), sensitizers, partialization accelerator, etc. The content ratio of other arbitrary components in this composition can be suitably selected according to each component within the range which does not impair the effect of this disclosure.

"Method for producing a radiation-sensitive composition" The present composition can be produced, for example, by mixing components such as (A) a polymer and (B) an acid generator, and if necessary (C) an acid diffusion control agent and (D) a solvent, in desired It is preferable to filter the obtained mixture using a filter (for example, a filter with a pore size of about 0.2 μm) or the like. The solid content concentration of the composition is preferably 0.1 mass % or more, more preferably 0.5 mass % or more, and still more preferably 1 mass % or more. In addition, the solid content concentration of the composition is preferably 50% by mass or less, more preferably 20% by mass or less, and still more preferably 5% by mass or less. By setting the solid content concentration of the present composition to be in the above-mentioned range, the coating properties can be made favorable and the shape of the resist pattern can be made favorable, which is suitable in this respect.

The present composition thus obtained can also be used as a composition for positive pattern formation using an alkaline developer to form a pattern, or as a composition for negative pattern formation using a developer containing an organic solvent.

"Method for forming a resist pattern" The resist pattern forming method in the present disclosure includes: a step of applying the composition on one side of a substrate (hereinafter, also referred to as "coating step"); A step of exposing the agent film (hereinafter, also referred to as an "exposure step"); and a step of developing the exposed resist film (hereinafter, also referred to as a "development step"). As a pattern formed by the resist pattern of this disclosure, a line-and-space pattern, a hole pattern, etc. are mentioned, for example. In the resist pattern forming method of the present disclosure, since a resist film is formed using the composition, a resist pattern with good sensitivity, small CDU, and few development residues can be formed. Hereinafter, each step will be described.

[coating step] In this step, a resist film is formed on the substrate by coating one side of the substrate with the composition. As the substrate on which the resist film is formed, a conventionally known substrate can be used, and examples thereof include a silicon wafer, a silicon dioxide, and an aluminum-coated wafer. In addition, for example, an organic or inorganic antireflection film disclosed in Japanese Patent Laid-Open No. 6-12452 or Japanese Patent Laid-Open No. 59-93448 can be formed on a substrate and used. As a coating method of this composition, spin coating (spin coating), casting coating, roll coating, etc. are mentioned, for example. After coating, in order to volatilize the solvent in the coating film, prebake (PB) can also be performed. The temperature of PB is preferably 60°C or higher, more preferably 80°C or higher. In addition, the temperature of the PB is preferably 140°C or lower, more preferably 120°C or lower. The time of PB is preferably 5 seconds or more, more preferably 10 seconds or more. In addition, the time of PB is preferably 600 seconds or less, more preferably 300 seconds or less. The average thickness of the formed resist film is preferably 10 nm to 1,000 nm, more preferably 20 nm to 500 nm.

[Exposure step] In this step, the resist film obtained by the coating step is exposed to light. This exposure is performed by irradiating the resist film with radiation through a liquid immersion medium such as a photomask and, if necessary, water. Examples of the radiation 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 these, the radiation irradiated to the resist film formed using the composition is preferably far ultraviolet, EUV or electron beam, more preferably ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 193 nm) 248 nm), EUV or electron beam, more preferably ArF excimer laser light, EUV or electron beam, still more preferably EUV or electron beam, particularly preferably EUV.

Preferably, a post exposure bake (Post Exposure Bake, PEB) is performed after the exposure. It is considered that the dissociation of the acid dissociable group is accelerated by the acid generated from the acid generating compound by the exposure in the exposed portion of the resist film by this PEB. Thereby, the difference of the solubility with respect to a developing solution can be enlarged in an exposed part and an unexposed part. The temperature of PEB is preferably 50°C or higher, more preferably 80°C or higher. In addition, the temperature of PEB is preferably 180°C or lower, more preferably 130°C or lower. The time of PEB is preferably 5 seconds or more, more preferably 10 seconds or more. In addition, the time of PEB is preferably 600 seconds or less, more preferably 300 seconds or less.

[Development step] In this step, the exposed resist film is developed. Thereby, a desired resist pattern can be formed. Usually, it wash|cleans with the rinse liquid, such as water or alcohol, after image development, and it is dried. The developing method in the developing step may be alkali development or organic solvent development.

In the case of alkali development, as a developer for development, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia water, ethylamine, n-propylamine can be mentioned. , Diethylamine, Di-n-propylamine, Triethylamine, Methyldiethylamine, Ethyldimethylamine, Triethanolamine, Tetramethyl Ammonium Hydroxide (TMAH), Pyrrole, Basic compounds such as 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 of them, etc. Among these, TMAH aqueous solution is preferable, and 2.38 mass % TMAH aqueous solution is more preferable.

In the case of organic solvent development, as the developer, one or two or more of various organic solvents (for example, hydrocarbons, ethers, esters, ketones, alcohols, etc.) can be mentioned. As a specific example of the organic solvent used as a developer, the solvent mentioned as (D) solvent in the description of this composition is mentioned, for example. Among these, esters and ketones are preferable as the developer used for organic solvent development. As esters, acetates are preferable, and n-butyl acetate is more preferable. As ketones, chain ketones are preferable, and 2-heptanone is more preferable. In the developer, the content of the organic solvent 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.

Examples of the developing method include: a method of immersing the substrate in a tank filled with a developer for a certain period of time (dipping method); Liquid (puddle) method); the method of spraying developer on the surface of the substrate (spray method); the method of continuously spraying the developer on the substrate rotating at a certain speed while scanning the developer ejection nozzle at a certain speed (dynamic distribution method) Wait. [Example]

Hereinafter, the present disclosure will be specifically described based on examples, but the present disclosure is not limited to these examples. The measurement method of each physical property value is shown below.

[Weight-average molecular weight and number-average molecular weight] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polymer were determined by gel permeation chromatography (GPC) using a GPC column (Tosoh) Two "G2000HXL", one "G3000HXL" and one "G4000HXL") were measured under the following conditions. Eluent: Tetrahydrofuran (Wako Pure Chemical Industries, Ltd.) Flow rate: 1.0 mL/min Sample concentration: 1.0% by mass Sample injection amount: 100 μL Column temperature: 40°C Detector: Differential refractometer Standard material: Monodisperse polyphenylene Ethylene [ ¹ H-NMR] ¹ H-NMR analysis was performed using a nuclear magnetic resonance apparatus (“JNM-ECZS400” from JEOL Ltd.).

The structures of the radiation-sensitive acid generator (PAG), the acid diffusion controller, and the highly fluorine-containing resin used in the preparation of the radiation-sensitive resin composition are shown below.

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[Radiation-Sensitive Acid Generators (PAGs)] The structures of the radiation-sensitive acid generators (PAG1 to PAG17) used in the following examples are as follows. PAG1 to PAG17 were synthesized by ion exchange of an ammonium salt of a sulfonic acid providing an organic anion moiety, and periconium chloride or iodochloride providing an onium cation moiety, respectively. Furthermore, PAG1 to PAG7, PAG9, PAG11 to PAG14, and PAG17 are radiation-sensitive acid generators having a specific cationic structure [X]. For example, the number of substituent β of PAG1 is two, and the number of substituent β of PAG2 is two. [Chemical 31]

[Chemical 32]

[Chemical 33]

[Acid Diffusion Control Agent] The structures of the acid diffusion control agents (Q-1 to Q-7) used in the following examples are as follows. Furthermore, Q-2 and Q-4 are acid diffusion control agents having a specific cationic structure [X]. [Chemical 34]

[High fluorine-containing resin] The structure and physical properties of the high-fluorine-containing resin (F-1) used in the following examples are as follows. F-1: Mw=8,900, Mw/Mn=2.0 [Chem.35]

[Synthesis of Base Resins (P-1 to P-9)] The monomers were combined and copolymerized in a solvent of tetrahydrofuran (THF). After crystallizing in methanol, further washing with hexane repeatedly, separation and drying were carried out. Thereby, polymers P-1 to P-9 were obtained as polymers having the following compositions (mol ratios) (referred to as "base resins"). The composition of the obtained base resin was confirmed by ¹ H-NMR, and the Mw and the degree of dispersion (Mw/Mn) were confirmed by GPC (solvent: THF, standard: polystyrene). Polymer P-1: Mw=7,400, Mw/Mn=1.9 Polymer P-2: Mw=7,800, Mw/Mn=1.8 Polymer P-3: Mw=7,800, Mw/Mn=1.8 Polymer P-4 : Mw=7,800, Mw/Mn=1.8 Polymer P-5: Mw=8,100, Mw/Mn=1.8 Polymer P-6: Mw=9,700, Mw/Mn=1.7 Polymer P-7: Mw=9,100, Mw/Mn=1.7 Polymer P-8: Mw=8,300, Mw/Mn=1.8 Polymer P-9: Mw=10,100, Mw/Mn=1.8 Furthermore, P-2, P-5, P-6, P-8 is a polymer having a specific cationic structure [X].

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(Composition of base resin) [Chemical 36]

[Chemical 37]

[Chemical 38]

[Chemical 39]

[Example 1 to Example 21, Comparative Example 1 to Comparative Example 3] 1. Preparation of the radiation-sensitive resin composition Each component was melt|dissolved by the composition shown in Table 1 in the solvent which melt|dissolved 100 ppm of FC-4430 made by 3M company as a surfactant. The obtained solution was filtered with a membrane filter having a size of 0.2 μm to prepare a radiation-sensitive resin composition.

2. Evaluation of sensitivity based on EUV exposure Using a spin coater (“CLEAN TRACK ACT12” of Tokyo Electron Co., Ltd.), the composition for forming an underlayer film (Brewer) was applied. Technology ("ARC66" from Brewer Science) was coated on a 12-inch silicon wafer and heated at 205°C for 60 seconds to form an underlayer film with an average thickness of 105 nm. Each radiation-sensitive resin composition shown in Table 1 was applied on the underlayer film using the spin coater, and PB was performed at 130° C. for 60 seconds. Thereafter, it was cooled at 23° C. for 30 seconds, whereby a resist film having an average thickness of 55 nm was formed. The resist film was masked using an EUV scanner (ASML "NXE3300" (NA 0.33, σ 0.9/0.6, quadrupole illumination, hole pattern on the wafer with a pitch of 46 nm, +20% bias) )) for exposure. PEB was performed on a hot plate at 120° C. for 60 seconds, and development was performed with a 2.38 mass % tetramethylammonium hydroxide (TMAH) aqueous solution for 30 seconds to form a resist pattern with holes of 23 nm and a pitch of 46 nm. The exposure amount for forming the resist pattern with the 23 nm hole and 46 nm pitch was defined as the optimum exposure amount (Eop), and the optimum exposure amount was defined as the sensitivity (mJ/cm ² ).

3. CDU evaluation The exposure amount of Eop obtained above was irradiated, and the same operation as in 2. above was carried out to form a resist pattern with holes of 23 nm and pitch of 46 nm. The formed resist pattern was observed from the upper part of the pattern using a scanning electron microscope ("CG-5000" from Hitachi High-Technologies). In the range of diameter 500 nm, the pore diameter of 16 points was measured, the average value was calculated|required, and this operation was repeated, and the average value of a total of 500 points was measured at arbitrary points. The 3-sigma value was obtained from the distribution of the measured values, and the obtained 3-sigma value was used as an evaluation value (nm) of CDU performance. Regarding the CDU performance, the smaller the evaluation value, the smaller the variation of the pore diameter in the long period, and the better. The results are shown in Table 1.

4. Evaluation of Development Residues The same operations as described in 2. above were carried out until the operation to form a resist film having an average thickness of 55 nm was performed to prepare a wafer on which the resist film was formed. Next, the entire surface of the resist film was exposed at an optimum exposure amount using an EUV scanner, and then PEB was performed on a hot plate at 120° C. for 60 seconds. Next, it developed with 2.38 mass % TMAH aqueous solution for 30 second, rinsed with pure water for 30 second, and dried. Thus, the wafer for development residue evaluation was produced. The wafer for evaluation was observed with a defect inspection apparatus COMPLUS (manufactured by AMAT Corporation), and residue defects were confirmed using a defect review SEM RS5500 (manufactured by Hitachi High-Technologies Co., Ltd.). presence or absence, count the number of residual defects. The following indexes were used for evaluation based on the number of residue defects counted. A: 5 or more B: 6 to 10 C: 11～20 D: 21 or more

[Table 1] Radiation sensitive resin composition Evaluation Base resin (parts by mass) PAG (parts by mass) Acid diffusion control agent (parts by mass) High fluorine-containing resin (parts by mass) Solvent (parts by mass) Sensitivity (mJ/cm ² ) CDU (nm) Development residue Example 1 P-1 (100) PAG1 (8.0) Q-1 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 15 2.3 C Example 2 P-1 (100) PAG2 (8.0) Q-1 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 15 2.3 C Example 3 P-1 (100) PAG3 (8.0) Q-1 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 15 2.3 B Example 4 P-1 (100) PAG4 (8.0) Q-1 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 15 2.3 B Example 5 P-1 (100) PAG5 (8.0) Q-1 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 14 2.3 A Example 6 P-1 (100) PAG6 (8.0) Q-1 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 14 2.3 A Example 7 P-1 (100) PAG7 (8.0) Q-1 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 13 2.3 A Example 8 P-1 (100) PAG8 (8.0) Q-2 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 15 2.3 B Example 9 P-2 (100) PAG8 (8.0) Q-1 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 15 2.3 B Example 10 P-1 (100) PAG9 (8.0) Q-3 (3.0) F-1 (3.0) PGMEA/DAA (2,000/500) 15 2.3 B Example 11 P-3 (100) PAG9 (8.0) Q-1 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 15 2.3 B Example 12 P-1 (100) PAG10 (8.0) Q-4 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 15 2.3 B Example 13 P-4 (100) PAG8 (8.0) Q-4 (3.5) F-1 (3.0) PGMEA/CHN/PGME (1,000/1,500/400) 15 2.3 B Example 14 P-5 (100) PAG10 (8.0) Q-1 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 15 2.3 B Example 15 P-5 (100) PAG8 (8.0) Q-5 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 15 2.3 B Example 16 P-5 (100) PAG11 (8.0) Q-1 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 14 2.3 B Example 17 P-6 (100) PAG8 (7.0) Q-4 (4.0) F-1 (3.0) PGMEA/GBL (2,200/300) 14 2.3 B Example 18 P-6 (100) PAG12 (7.0) Q-6 (4.0) F-1 (3.0) PGMEA/GBL (2,200/300) 13 2.2 A Example 19 P-7 (100) PAG13 (8.0) Q-4 (4.0) F-1 (3.0) PGMEA/GBL (2,200/300) 14 2.5 B Example 20 P-7 (100) PAG14 (8.0) Q-7 (3.5) F-1 (3.0) PGMEA/GBL (2,200/300) 14 2.5 B Example 21 P-8 (100) - Q-1 (4.0) F-1 (3.0) PGMEA/GBL (2,200/300) 14 2.5 B Comparative Example 1 P-1 (100) PAG15 (8.0) Q-1 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 16 2.3 D Comparative Example 2 P-1 (100) PAG16 (8.0) Q-1 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 16 2.5 D Comparative Example 3 P-9 (100) PAG17 (10.0) Q-1 (4.0) F-1 (3.0) PGMEA/DAA (2,000/500) 15 2.6 B

In Table 1, the details of the solvent are as follows. PGMEA (Propylene Glycol Monomethyl Ether Acetate) GBL (gamma-butyrolactone) CHN (cyclohexanone) PGME (Propylene Glycol Monomethyl Ether) DAA (Diacetone Alcohol)

As a result of evaluating the resist pattern formed by EUV exposure, the radiation-sensitive resin compositions of Examples 1 to 21 had good sensitivity and CDU performance, and also had few development residues. Among them, the development residues of the radiation-sensitive resin compositions of Examples 3 to 21 containing a radiosensitive onium cation having a total number of fluorine groups and fluoroalkyl groups of 3 or more as the specific cation structure [X] were 10 or less, A rating of "A" or "B". In addition, when the total number of the fluorine group and the fluoroalkyl group in the specific cationic structure [X] is 4 or more, the effect of reducing the development residue is particularly excellent.

On the other hand, the comparative example 1 and the comparative example 2 which contain the polymer [P] but do not contain the specific cationic structure [X] have low sensitivity compared with Example 1 - Example 21, and also have many image development residues. Sensitivity of Comparative Example 3, Examples 1 to 4, and Example 8, in which a polymer (polymer [P]) having a radiosensitive onium cation structure and an organic anion structure is not included although the specific cation structure [X] is included ~Example 15 is about the same, but the CDU performance is poor.

According to the radiation-sensitive resin composition and the resist pattern forming method described above, a resist pattern having good sensitivity to exposure light and excellent CDU performance and development residue suppression can be formed. Therefore, these can be suitably used for the processing process etc. of the semiconductor device which is expected to be further miniaturized in the future.

none

Claims (10)

A radiation-sensitive composition comprising a polymer [P] having a radiation-sensitive onium cation structure and an organic anion structure, and satisfying at least any one of the following (i) and (ii), (i) A radiosensitive onium cation structure containing at least one substituent β selected from the group consisting of 2 or more fluoroalkyl groups and fluorine groups (excluding fluorine groups in fluoroalkyl groups) a polymer as said polymer [P]; (ii) further comprising a compound [Q] having a radiation-sensitive onium cation structure and an organic anion structure (except for the polymer [P]), and comprising a radiation-sensitive compound having two or more of the substituents β A compound having an onium cation structure is used as the compound [Q]. The radiation-sensitive composition according to claim 1, wherein the radiation-sensitive onium cation structure having two or more of the substituents β has a pernium cation structure or an iodonium cation structure. The radiation-sensitive composition according to claim 2, wherein the radiation-sensitive onium cation structure having two or more of the substituents β contains one or more aromatic rings Z bonded to periconium cations or iodonium cations, and A structure in which two or more of the substituents β are bonded to one or more of the same aromatic rings in the aromatic ring Z, or a structure in which two or more of the aromatic rings Z are bonded to the aromatic ring A structure in which one or more of the substituents β are each bonded to two or more different aromatic rings in Z. The radiation-sensitive resin composition according to any one of Claims 1 to 3, wherein the polymer [P] contains a structural unit having an acid dissociable group. The radiation-sensitive resin composition according to any one of Claims 1 to 4, wherein the polymer [P] contains a structural unit having a hydroxyl group bonded to an aromatic ring. The radiation-sensitive composition according to any one of Claims 1 to 5, which is used to form a resist pattern by exposure to extreme ultraviolet rays. The radiation-sensitive composition according to any one of Claims 1 to 6, wherein the polymer [P] contains a structural unit derived from a monomer represented by the following formula (3B),

(In formula (3B), L ⁷ is a group participating in polymerization; Z ⁺ is a radioactive onium cation; "L ⁷ -M ^- " is an organic anion). The radiation-sensitive composition according to any one of Claims 1 to 7, comprising a first acid generator and an acid that is weaker than the acid generated by the first acid generator by exposure to light The second acid-generating body is used as the compound [Q]. A resist pattern forming method, comprising: A step of forming a resist film on a substrate using the radiation-sensitive composition according to any one of claim 1 to claim 8; the step of exposing the resist film; and A step of developing the exposed resist film. The resist pattern forming method according to claim 9, wherein the resist film is exposed to light using extreme ultraviolet rays.