Compound

Abstract

To provide a radiation-sensitive resin composition with superior sensitivity and a broad process window, a method of forming a resist pattern, and a compound.SOLUTION: The invention provides a compound represented by the formula (1) in the figure. In the formula (1), R1 is a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms; Xn+ is an n-valent cation; and n is an integer from 1 to 3.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a radiation-sensitive resin composition, a method for forming a resist pattern, and a compound. [Background technology]

[0002] With the miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, there is a demand for further miniaturization of resist patterns in lithography processes, and for this reason, various radiation-sensitive resin compositions have been studied. Such radiation-sensitive resin compositions generate an acid in exposed areas when irradiated with exposure light such as far ultraviolet light from an ArF excimer laser, extreme ultraviolet light (EUV), or electron beams, and the catalytic action of this acid creates a difference in dissolution rate in a developer between exposed and unexposed areas, forming a resist pattern on a substrate.

[0003] Such radiation-sensitive resin compositions are required to have excellent resolution. In response to this requirement, various polymer structures have been investigated for use in radiation-sensitive resin compositions, and it is known that the inclusion of a lactone structure such as a butyrolactone structure or a norbornane lactone structure can increase the adhesion of a resist pattern to a substrate and improve these performances (see JP-A-11-212265, JP-A-2003-5375, and JP-A-2008-83370). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-212265 [Patent Document 2] JP 2003-5375 A [Patent Document 3] JP 2008-83370 A Summary of the Invention [Problem to be solved by the invention]

[0005] As resist patterns become finer, extreme ultraviolet rays (EUV) and electron beams are being used as exposure light, and improving the sensitivity of radiation-sensitive resin compositions is becoming an issue. In addition, as resist patterns become finer, the impact of slight variations in exposure and development conditions on the shape of resist patterns and the occurrence of defects becomes increasingly large. There is also a demand for radiation-sensitive resin compositions with a wide process window (process margin) that can absorb such slight variations in process conditions. However, the above-mentioned conventional radiation-sensitive resin compositions cannot meet these requirements.

[0006] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a radiation-sensitive resin composition, a method for forming a resist pattern, and a compound which have excellent sensitivity and a wide process window. [Means for solving the problem]

[0007] The invention made to solve the above-mentioned problems is a radiation-sensitive resin composition containing a polymer having a structural unit containing an acid-dissociable group (hereinafter also referred to as "polymer [A]"), a radiation-sensitive acid generator (hereinafter also referred to as "acid generator [B]"), and a compound represented by the following formula (1) (hereinafter also referred to as "compound [C]"). [ka] (In formula (1), R 1 is a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms. n+ is a radiation-sensitive onium cation having a valence of n, where n is an integer of 1 to 3.

[0008] Another invention made to solve the above-mentioned problems is a method for forming a resist pattern, comprising the steps of: applying the radiation-sensitive resin composition directly or indirectly onto a substrate; exposing a resist film formed by the applying step; and developing the resist film after the exposing step.

[0009] Yet another invention made to solve the above problems is a compound represented by the following formula (1). [ka] (In formula (1), R 1 is a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms. n+ is an n-valent cation, where n is an integer from 1 to 3.

[0010] As used herein, the term "organic group" refers to a group containing at least one carbon atom. Effect of the Invention

[0011] According to the radiation-sensitive resin composition and the method for forming a resist pattern of the present invention, a resist pattern can be formed with excellent sensitivity and a wide process window. The compound of the present invention can be suitably used as a component of the radiation-sensitive resin composition. Therefore, they can be suitably used in the processing of semiconductor devices, which are expected to become increasingly finer in the future. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] <Radiation sensitive resin composition> The radiation-sensitive resin composition contains a polymer [A], an acid generator [B], and a compound [C]. The radiation-sensitive resin composition usually contains a solvent (hereinafter also referred to as "solvent [D]"), and may contain other optional components within the scope not impairing the effects of the present invention.

[0013] The radiation-sensitive resin composition contains the polymer [A], the acid generator [B], and the compound [C], and therefore has excellent sensitivity and a wide process window. The reason why the radiation-sensitive resin composition has the above-mentioned structure and exhibits the above-mentioned effects is not necessarily clear, but can be presumed, for example, as follows. That is, the compound [C] has -COO -The fluorine atom in the -CF2CF2- group absorbs exposure light such as EUV and promotes the generation of acid from the acid generator [B] through the generation of secondary electrons, etc., which is considered to result in an improvement in the sensitivity of the radiation-sensitive resin composition. In addition, the compound [C] has a suitable hydrophobicity and has a -CF2CF2- group adjacent to the -COO - It is believed that the group having an appropriate basicity can effectively exert an acid diffusion control property, which results in a better resist pattern shape and a wider process window. Each component will be described below.

[0014] <[A] Polymer> The polymer [A] is a polymer having a structural unit containing an acid-dissociable group (hereinafter also referred to as "structural unit (I)"). The "acid-dissociable group" refers to a group that substitutes a hydrogen atom of a carboxy group, a hydroxy group, or the like, and dissociates by the action of an acid.

[0015] The polymer [A] preferably has a structural unit containing a phenolic hydroxyl group (hereinafter also referred to as "structural unit (II)") in addition to the structural unit (I), and may have a structural unit other than the structural units (I) and (II). Each structural unit will be described below.

[0016] Structural Units The structural unit (I) is a structural unit containing an acid-dissociable group.

[0017] Examples of the structural unit (I) include structural units represented by the following formula (2-1A), (2-1B), (2-2A) or (2-2B) (hereinafter also referred to as "structural units (I-1A), (I-1B), (I-2A) or (I-2B)"), and structural units containing an acetal structure (hereinafter also referred to as "structural unit (I-3)").

[0018] [ka]

[0019] In the above formula (2-1A), R T R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X R is a monovalent hydrocarbon group having 1 to 20 carbon atoms or a hydrogen atom. Y and R Z are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or R Y and R Z are combined with each other and are part of an alicyclic structure having 3 to 20 ring members formed together with the carbon atoms to which they are bonded.

[0020] In the above formula (2-1B), R T R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X R is a monovalent hydrocarbon group having 1 to 20 carbon atoms. Y and R Z are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or R Y and R Z are combined with each other and are part of an alicyclic structure having 3 to 20 ring members formed together with the carbon atoms to which they are bonded.

[0021] In the above formula (2-2A), R T R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. U R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms. V and R W are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or R V and R W are combined together and R U is part of an aliphatic heterocyclic structure having 4 to 20 ring members, which is formed together with the carbon atom to which it is bonded and the oxygen atom adjacent to this carbon atom.

[0022] In the above formula (2-2B), R T R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. U R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms.V and R W are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms, or R V and R W are combined together and R U is part of an aliphatic heterocyclic structure having 4 to 20 ring members, which is formed together with the carbon atom to which it is bonded and the oxygen atom adjacent to this carbon atom.

[0023] In the structural units (I-1A) to (I-2B), -CR is bonded to an oxyoxygen atom derived from a carboxyl group or a phenolic hydroxyl group. X R Y R Z or -CR U R V (OR W ) is an acid-dissociable group.

[0024] R T From the viewpoint of copolymerizability of the monomer that gives the structural unit (I), a hydrogen atom or a methyl group is preferred.

[0025] The term "hydrocarbon group" includes linear hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. This "hydrocarbon group" may be a saturated or unsaturated hydrocarbon group. The term "linear hydrocarbon group" refers to a hydrocarbon group that does not include a cyclic structure and is composed only of a linear structure, and includes both linear and branched hydrocarbon groups. The term "alicyclic hydrocarbon group" refers to a hydrocarbon group that includes only an alicyclic structure as a ring structure and does not include an aromatic ring structure, and includes both monocyclic alicyclic hydrocarbon groups and polycyclic alicyclic hydrocarbon groups. However, it is not necessary for the group to be composed only of an alicyclic structure, and it may include a linear structure as a part of the ring structure. The term "aromatic hydrocarbon group" refers to a hydrocarbon group that includes an aromatic ring structure as a ring structure. However, it is not necessary for the group to be composed only of an aromatic ring structure, and it may include a linear structure or an alicyclic structure as a part of the ring structure. The "number of ring members" refers to the number of atoms constituting the ring of an alicyclic structure, an aromatic ring structure, an aliphatic heterocyclic structure, or an aromatic heterocyclic structure, and in the case of a polycyclic structure, refers to the number of atoms constituting the polycyclic structure.

[0026] R X , R Y , RZ , R U , R V and R W Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) include a monovalent chain hydrocarbon group having 1 to 20 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms.

[0027] Examples of the monovalent chain hydrocarbon group having 1 to 20 carbon atoms include Alkyl groups such as a methyl group, an ethyl group, an n-propyl group, or an i-propyl group; alkenyl groups such as ethenyl, propenyl, and butenyl; Examples of the alkynyl group include an ethynyl group, a propynyl group, and a butynyl group.

[0028] Examples of the monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms include Monocyclic alicyclic saturated hydrocarbon groups such as cyclopentyl group, cyclohexyl group, etc.; Monocyclic alicyclic unsaturated hydrocarbon groups such as cyclopentenyl and cyclohexenyl groups; Polycyclic alicyclic saturated hydrocarbon groups such as a norbornyl group, an adamantyl group, and a tricyclodecyl group; Examples of the unsaturated hydrocarbon groups include polycyclic alicyclic unsaturated hydrocarbon groups such as norbornenyl and tricyclodecenyl.

[0029] Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms include Aryl groups such as a phenyl group, a tolyl group, a xylyl group, a naphthyl group, or an anthryl group; Examples of the aryl group include aralkyl groups such as a benzyl group, a phenethyl group, a naphthylmethyl group, and an anthrylmethyl group.

[0030] R Y and R Z Examples of the alicyclic structure having 3 to 20 carbon atoms formed by the above together with the carbon atom include Monocyclic alicyclic structures such as a cyclopropane structure, a cyclobutane structure, a cyclopentane structure, a cyclohexane structure, a cyclopentene structure, and a cyclohexene structure; Examples of the polycyclic alicyclic structure include a norbornane structure and an adamantane structure.

[0031] R V and R W Examples of the aliphatic heterocyclic structure having 4 to 20 carbon atoms formed by the above together with carbon atoms and oxygen atoms include monocyclic aliphatic heterocyclic structures such as an oxacyclobutane structure, an oxacyclopentane structure, an oxacyclohexane structure, an oxacyclopentene structure, or an oxacyclohexene structure; Examples of the heterocyclic structure include polycyclic aliphatic heterocyclic structures such as an oxanorbornane structure and an oxadamantane structure.

[0032] As the structural unit (I-1A), structural units represented by the following formulas (2-1A-1) to (2-1A-6) (hereinafter also referred to as "structural units (I-1A-1) to (I-1A-6)") are preferable.

[0033] [ka]

[0034] In the above formulas (2-1A-1) to (2-1A-5), R T , R X , R Y and R Z has the same meaning as in the above formula (2-1A). i and j each independently represent an integer of 1 to 4.

[0035] In the above formula (2-1A-6), R T has the same meaning as in formula (2-1A). s is an integer of 1 to 4. R S1 and R S2 are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms.

[0036] R X As the alkyl group, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms is preferable, and a methyl group, an ethyl group, an i-propyl group, a t-butyl group or a phenyl group is more preferable. R S1 and RS2 is preferably a hydrogen atom or a methyl group. As i and j, 1 or 2 is preferable. As s, 2 is preferable.

[0037] The structural unit (I) is preferably the structural unit (I-1A), and more preferably the structural unit (I-1A-1) or the structural unit (I-1A-6).

[0038] (Structural unit (I-3)) The structural unit (I-3) is a structural unit containing an acetal structure. Examples of groups containing an acetal structure include a group represented by the following formula (3) (hereinafter, also referred to as "group (X)"). The group (X) is decomposed by the action of an acid to form *-R I -OH, R J R K C=O and R L OH is produced. -CR J R K (OR L ) is an acid-dissociable group.

[0039] [ka]

[0040] In the above formula (3), R I is a single bond or a divalent hydrocarbon group having 1 to 20 carbon atoms, R J and R K are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, R L is a monovalent hydrocarbon group having 1 to 20 carbon atoms, or R I , R J , R K and R L Two or more of the above are combined with each other to form a part of a ring structure having 3 to 20 ring members, together with the carbon atoms or atomic chains to which they are bonded. * indicates a bonding site to a portion of the structural unit (I-3) other than the above group (X).

[0041] R IExamples of the divalent hydrocarbon group having 1 to 20 carbon atoms represented by the above R X , R Y and R Z Examples of the monovalent hydrocarbon groups include those having 1 to 20 carbon atoms, each of which has one hydrogen atom removed.

[0042] R I is preferably a single bond or a divalent chain hydrocarbon group having 1 to 20 carbon atoms, more preferably a divalent chain hydrocarbon group having 1 to 20 carbon atoms, further preferably an alkanediyl group having 1 to 10 carbon atoms, and particularly preferably a methanediyl group.

[0043] R J , R K and R L Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the above R X , R Y and R Z Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include the same groups as those exemplified above.

[0044] R J and R K R is preferably a hydrogen atom or a chain hydrocarbon group, more preferably a hydrogen atom or an alkyl group, and further preferably a hydrogen atom or a methyl group. Z As the alkyl group, a chain hydrocarbon group is preferable, an alkyl group is more preferable, and a methyl group is particularly preferable.

[0045] R I is preferably a single bond or a chain hydrocarbon group, more preferably a chain hydrocarbon group, further preferably an alkanediyl group, and particularly preferably a methanediyl group.

[0046] R I and R L Examples of the ring structure having 5 to 20 ring members formed together with the atomic chain include a 1,3-dioxacycloalkane structure such as a 1,3-dioxacyclopentane structure.

[0047] R J and R KExamples of the ring structure having 3 to 20 ring members formed by the ring structure together with the carbon atoms include cycloalkane structures such as a cyclopentane structure and a cyclohexane structure.

[0048] An example of the group (X) is a 2,2-dimethyl-1,3-dioxacyclopentan-4-yl group.

[0049] The lower limit of the content of the structural unit (I) is preferably 20 mol%, more preferably 40 mol%, and even more preferably 50 mol% based on the total structural units constituting the polymer [A]. The upper limit of the content is preferably 90 mol%, more preferably 80 mol%, and even more preferably 70 mol%. By setting the content of the structural unit (I) within the above range, the sensitivity and process window can be further improved.

[0050] [Structural unit (II)] The structural unit (II) is a structural unit containing a phenolic hydroxyl group. The term "phenolic hydroxyl group" refers not only to a hydroxyl group directly bonded to a benzene ring, but also to any hydroxyl group directly bonded to an aromatic ring. The polymer [A] having the structural unit (II) can increase the hydrophilicity of the resist film and appropriately adjust the solubility in the developer, thereby widening the process window. In addition, in the case of KrF exposure, EUV exposure, or electron beam exposure, the sensitivity can be further improved.

[0051] An example of the structural unit (II) is a structural unit represented by the following formula (P).

[0052] [ka]

[0053] In the above formula (P), R P R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Qis a single bond, -O-, -COO- or -CONH-. Ar is a group obtained by removing hydrogen atoms on (g+h+1) aromatic rings from an arene having 6 to 20 ring members. g is an integer of 0 to 10. When g is 1, R R is a monovalent organic group having 1 to 20 carbon atoms or a halogen atom. When g is 2 or more, multiple R R are the same or different and each is a monovalent organic group having 1 to 20 carbon atoms or a halogen atom, or a plurality of R R Two or more of the above are combined with each other to form a ring structure having 4 to 20 ring members together with the carbon chain to which they are bonded. h is an integer of 1 to 11, provided that g+h is 11 or less.

[0054] R P From the viewpoint of copolymerizability of the monomer that gives the structural unit (II), a hydrogen atom or a methyl group is preferable, and a hydrogen atom is more preferable.

[0055] R Q is preferably a single bond or -COO-, and more preferably a single bond.

[0056] R R Examples of the monovalent organic group having 1 to 20 carbon atoms and represented by the formula (I) include monovalent hydrocarbon groups having 1 to 20 carbon atoms, monovalent groups (α) containing a divalent heteroatom-containing group between the carbon atoms of this hydrocarbon group, monovalent groups (β) in which some or all of the hydrogen atoms in the above-mentioned hydrocarbon groups and groups (α) are substituted with monovalent heteroatom-containing groups, and monovalent groups (γ) in which the above-mentioned hydrocarbon groups, groups (α) or groups (β) are combined with a divalent heteroatom-containing group.

[0057] Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms include R X ~R W Examples of the monovalent hydrocarbon groups include the same groups as those having 1 to 20 carbon atoms exemplified as the monovalent hydrocarbon groups having 1 to 20 carbon atoms.

[0058] Examples of heteroatoms constituting the monovalent and divalent heteroatom-containing groups include oxygen atoms, nitrogen atoms, sulfur atoms, phosphorus atoms, silicon atoms, halogen atoms, etc. Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.

[0059] Examples of the divalent heteroatom-containing group include -O-, -CO-, -S-, -CS-, -NR'-, and groups formed by combining two or more of these. R' is a hydrogen atom or a monovalent hydrocarbon group. Of these, -CO- is preferred.

[0060] Examples of the monovalent heteroatom-containing group include a halogen atom, a hydroxy group, a carboxy group, a cyano group, an amino group, and a sulfanyl group.

[0061] Examples of arenes having 6 to 20 ring members that give Ar include benzene, naphthalene, anthracene, phenanthrene, tetracene, pyrene, etc. Among these, benzene or naphthalene is preferred, and benzene is more preferred.

[0062] R R As the alkyl group, a hydrocarbon group is preferable, and an alkyl group is more preferable.

[0063] Multiple R R Examples of the ring structure having 4 to 20 ring members formed by two or more of the above together with a carbon chain include alicyclic structures such as a cyclohexane structure and a cyclohexene structure.

[0064] g is preferably 0 to 2, more preferably 0 or 1, and further preferably 0.

[0065] As h, 1 to 3 is preferable, 1 or 2 is more preferable, and 1 is even more preferable.

[0066] Examples of the structural unit (II) include structural units represented by the following formulas (P-1) to (P-14) (hereinafter also referred to as "structural units (II-1) to (II-14)").

[0067] [ka]

[0068] In the above formulas (P-1) to (P-14), R P has the same meaning as formula (P) above.

[0069] Of these, the structural unit (II-1) or (II-2) is preferred.

[0070] When the polymer [A] has the structural unit (II), the lower limit of the content of the structural unit (II) is preferably 10 mol%, more preferably 20 mol%, and even more preferably 25 mol% based on the total structural units constituting the polymer [A]. The upper limit of the content is preferably 80 mol%, more preferably 60 mol%, and even more preferably 50 mol%. By setting the content of the structural unit (II) within the above range, the sensitivity and process window of the radiation-sensitive resin composition can be further improved.

[0071] The structural unit (II) can be formed, for example, by hydrolyzing a polymer obtained by using a monomer such as acyloxystyrene, eg, acetoxystyrene, in the presence of a base such as triethylamine.

[0072] <Other structural units> Examples of the other structural units include structural units containing an alcoholic hydroxyl group, structural units containing a lactone structure, a cyclic carbonate structure, a sultone structure, or a combination thereof, structural units containing a carboxy group, a cyano group, a nitro group, a sulfonamide group, or a combination thereof, and structural units containing a non-acid dissociable hydrocarbon group.

[0073] Examples of the structural unit containing an alcoholic hydroxyl group include structural units represented by the following formulas.

[0074] [ka]

[0075] In the above formula, R L2 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0076] When the polymer [A] has other structural units, the upper limit of the content of the other structural units is preferably 30 mol %, and more preferably 15 mol %, based on all structural units constituting the polymer [A].

[0077] The lower limit of the content of the polymer [A] is preferably 50% by mass, more preferably 70% by mass, and even more preferably 80% by mass, based on all components other than the solvent [D] in the radiation-sensitive resin composition, and the upper limit of the content is preferably 99% by mass, and more preferably 95% by mass.

[0078] The lower limit of the content of the polymer [A] in the radiation-sensitive resin composition is preferably 0.1% by mass, more preferably 0.5% by mass, and even more preferably 1% by mass. The upper limit of the content is preferably 50% by mass, more preferably 30% by mass, and even more preferably 10% by mass. The polymer [A] may contain one or more kinds.

[0079] <[A] Polymer synthesis method> The polymer (A) can be synthesized, for example, by polymerizing monomers that provide the respective structural units in a solvent using a radical polymerization initiator or the like.

[0080] The lower limit of the weight average molecular weight (Mw) of the polymer [A] in terms of polystyrene standards, as determined by gel permeation chromatography (GPC), is preferably 1,000, more preferably 3,000, even more preferably 4,000, and particularly preferably 5,000. The upper limit of the Mw is preferably 50,000, more preferably 30,000, even more preferably 20,000, and particularly preferably 10,000. By setting the Mw of the polymer [A] within the above range, the coatability of the radiation-sensitive resin composition can be improved, and as a result, the sensitivity and process window can be further improved.

[0081] The upper limit of the ratio (Mw / Mn) of Mw to the polystyrene-equivalent number average molecular weight (Mn) of the polymer [A] as determined by GPC is preferably 5, more preferably 3, still more preferably 2, and particularly preferably 1.6. The lower limit of the above ratio is usually 1, and preferably 1.1.

[0082] In this specification, the Mw and Mn of the polymer are values ​​measured by gel permeation chromatography (GPC) under the following conditions. GPC columns: 2 "G2000HXL", 1 "G3000HXL" and 1 "G4000HXL" from Tosoh Corporation Column temperature: 40℃ Dissolution solvent: Tetrahydrofuran (Fujifilm Wako Pure Chemical Industries, Ltd.) Flow rate: 1.0mL / min Sample concentration: 1.0% by mass Sample injection volume: 100μL Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0083] <[B] Acid generator> The acid generator [B] is a substance that generates an acid upon exposure to light. The generated acid dissociates an acid-dissociable group of the polymer [A] or the like to generate a carboxyl group, a hydroxyl group, or the like, and changes the solubility of the polymer [A] in a developer, allowing a resist pattern to be formed from the radiation-sensitive resin composition. The form in which the acid generator [B] is contained in the radiation-sensitive resin composition may be in the form of a low molecular weight compound (hereinafter also referred to as "acid generator [B]"), in the form incorporated as a part of a polymer, or in both of these forms.

[0084] Examples of the acid generated from the acid generator (B) include sulfonic acids and imide acids.

[0085] Examples of the acid generator (B) include an onium salt compound, an N-sulfonyloxyimide compound, a sulfonimide compound, a halogen-containing compound, and a diazoketone compound.

[0086] Examples of the onium salt compound include sulfonium salts, tetrahydrothiophenium salts, iodonium salts, phosphonium salts, diazonium salts, and pyridinium salts.

[0087] Specific examples of the acid generator (B) include the compounds described in paragraphs

[0080] to

[0113] of JP-A-2009-134088.

[0088] Examples of the acid generator (B) include compounds represented by the following formula (4).

[0089] [ka]

[0090] In the above formula (4), A - is a monovalent sulfonate anion or a monovalent imidate anion. + is a monovalent radiation-sensitive onium cation.

[0091] Examples of the acid generator [B] that generates a sulfonic acid upon exposure include a compound represented by the following formula (4-1) (hereinafter also referred to as "compound (4-1)"). When the acid generator [B] has the following structure, it is believed that the diffusion length of the acid generated upon exposure in the resist film is suitably shortened due to interaction with the polymer [A], etc., and as a result, the process window can be further widened.

[0092] [ka]

[0093] In the above formula (4-1), R p1 R is a monovalent group containing a ring structure having 5 or more ring members. p2 is a divalent linking group. p3 and R p4 R are each independently a hydrogen atom, a fluorine atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms, or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. p5 and R p6 are each independently a fluorine atom or a monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. p1 is an integer from 0 to 10. p2 is an integer from 0 to 10. p3 is an integer from 0 to 10. p1 +n p2 +n p3 is between 1 and 30. p1 If is 2 or more, multiple R p2 are the same or different. n p2 If is 2 or more, multiple R p3 are the same or different, and multiple R p4 are the same or different. n p3 If is 2 or more, multiple R p5 are the same or different, and multiple R p6 are the same or different. T + is a monovalent radiation-sensitive onium cation.

[0094] R p1Examples of the monovalent group containing a ring structure having 5 or more ring members include a monovalent group containing 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, and a monovalent group containing an aromatic heterocyclic structure having 5 or more ring members.

[0095] Examples of alicyclic structures having 5 or more ring members include Monocyclic saturated alicyclic structures such as a cyclopentane structure, a cyclohexane structure, a cycloheptane structure, a cyclooctane structure, a cyclononane structure, a cyclodecane structure, and a cyclododecane structure; Monocyclic unsaturated alicyclic structures such as cyclopentene structure, cyclohexene structure, cycloheptene structure, cyclooctene structure, and cyclodecene structure; Polycyclic saturated alicyclic structures such as norbornane structure, adamantane structure, tricyclodecane structure, and tetracyclododecane structure; Examples of the polycyclic unsaturated alicyclic structure include a norbornene structure and a tricyclodecene structure.

[0096] Examples of the aliphatic heterocyclic structure having 5 or more ring members include Lactone structures such as hexanolactone structures and norbornanelactone structures; Sultone structures such as a hexanosultone structure and a norbornanesultone structure; Oxygen atom-containing heterocyclic structures such as oxacycloheptane structure and oxanorbornane structure; Nitrogen atom-containing heterocyclic structures such as azacyclohexane structures and diazabicyclooctane structures; Examples of the heterocyclic structure include a sulfur atom-containing heterocyclic structure such as a thiacyclohexane structure or a thianorbornane structure.

[0097] Examples of aromatic ring structures having 5 or more ring members include a benzene structure, a naphthalene structure, a phenanthrene structure, and an anthracene structure.

[0098] Examples of aromatic heterocyclic structures having 5 or more ring members include Oxygen atom-containing heterocyclic structures such as a furan structure, a pyran structure, a benzofuran structure, and a benzopyran structure; Examples of the heterocyclic structure include a nitrogen atom-containing heterocyclic structure such as a pyridine structure, a pyrimidine structure, and an indole structure.

[0099] R p1 The lower limit of the number of ring members of the ring structure is preferably 6, more preferably 8, still more preferably 9, and particularly preferably 10. The upper limit of the number of ring members is preferably 15, more preferably 14, still more preferably 13, and particularly preferably 12. By setting the number of ring members within the above range, the diffusion length of the acid can be further suitably shortened, and as a result, the process window can be further widened.

[0100] R p1 A part or all of the hydrogen atoms in the ring structure may be substituted with a substituent. Examples of the substituent include halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom, hydroxy group, carboxy group, cyano group, nitro group, alkoxy group, alkoxycarbonyl group, alkoxycarbonyloxy group, acyl group, and acyloxy group. Among these, a hydroxy group is preferred.

[0101] R p1 is preferably a monovalent group containing an alicyclic structure having 5 or more ring members or a monovalent group containing an aromatic ring structure having 6 or more ring members.

[0102] R p2 Examples of the divalent linking group represented by the formula (I) include a carbonyl group, an ether group, a carbonyloxy group, a sulfide group, a thiocarbonyl group, a sulfonyl group, a divalent hydrocarbon group, etc. Among these, a carbonyloxy group, a sulfonyl group, an alkanediyl group, or a divalent alicyclic saturated hydrocarbon group is preferred, a carbonyloxy group or a divalent alicyclic saturated hydrocarbon group is more preferred, a carbonyloxy group or a norbornanediyl group is even more preferred, and a carbonyloxy group is particularly preferred.

[0103] R p3 and R p4 Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) include an alkyl group having 1 to 20 carbon atoms.p3 and R p4 Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) include a fluorinated alkyl group having 1 to 20 carbon atoms. p3 and R p4 is preferably a hydrogen atom, a fluorine atom or a fluorinated alkyl group, more preferably a fluorine atom or a perfluoroalkyl group, and further preferably a fluorine atom or a trifluoromethyl group.

[0104] R p5 and R p6 Examples of the monovalent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by the formula (I) include a fluorinated alkyl group having 1 to 20 carbon atoms. p5 and R p6 As the alkyl group, a fluorine atom or a fluorinated alkyl group is preferable, a fluorine atom or a perfluoroalkyl group is more preferable, a fluorine atom or a trifluoromethyl group is further preferable, and a fluorine atom is particularly preferable.

[0105] n p1 As the number, 0 to 5 is preferable, 0 to 3 is more preferable, 0 to 2 is further preferable, and 0 or 1 is particularly preferable.

[0106] n p2 As the number, 0 to 5 is preferable, 0 to 2 is more preferable, 0 or 1 is further preferable, and 0 is particularly preferable.

[0107] n p3 The lower limit of n is preferably 1, and more preferably 2. p3 By making n equal to or greater than 1, the strength of the acid generated from compound (4-1) can be increased, and as a result, the process window can be broadened. p3 The upper limit of is preferably 8, more preferably 6, and even more preferably 4.

[0108] n p1 +n p2 +n p3 The lower limit of n is preferably 2, and more preferably 4. p1 +n p2 +np3 The upper limit of is preferably 20, more preferably 10.

[0109] T + Examples of the monovalent radiation-sensitive onium cation represented by the formula (T-1) below (hereinafter also referred to as "cation (T-1)"), the cation represented by the formula (T-2) below (hereinafter also referred to as "cation (T-2)"), and the cation represented by the formula (T-3) below (hereinafter also referred to as "cation (T-3)") can be mentioned.

[0110] [ka]

[0111] In the above formula (T-1), R a1 and R a2 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 a3 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, a nitro group, or a halogen atom. When k1 is 2 to 5, multiple R a3 are the same or different and each is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, a nitro group, or a halogen atom, or a plurality of R a3 are combined with each other and are part of a ring structure having 4 to 20 ring members formed together with the carbon chain to which they are bonded. t1 is an integer of 0 to 3.

[0112] R a1 , R a2 and R a3 Examples of the monovalent organic group having 1 to 20 carbon atoms represented by the formula (P) include R R Examples of the monovalent organic groups having 1 to 20 carbon atoms include the same groups as those exemplified as the monovalent organic groups having 1 to 20 carbon atoms.

[0113] R a1 and R a2is preferably a monovalent unsubstituted hydrocarbon group having 1 to 20 carbon atoms or a hydrocarbon group in which a hydrogen atom is substituted with a substituent, more preferably a monovalent unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms or an aromatic hydrocarbon group in which a hydrogen atom is substituted with a substituent, further preferably a substituted or unsubstituted phenyl group, and particularly preferably an unsubstituted phenyl group.

[0114] R a1 and R a2 Examples of the substituent that may replace a hydrogen atom of the monovalent hydrocarbon group having 1 to 20 carbon atoms, represented by the following formula, include a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, -OSO2-R k , -SO2-R k , -OR k , -COOR k , -O-CO-R k , -OR kk -COOR k , -R kk -CO-R k or -SR k is preferred. k R is a monovalent hydrocarbon group having 1 to 10 carbon atoms. kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

[0115] R a3 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, -OSO2-R k , -SO2-R k , -OR k , -COOR k , -O-CO-R k , -OR kk -COOR k , -R kk -CO-R k or -SR k is preferred. k R is a monovalent hydrocarbon group having 1 to 10 carbon atoms. kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

[0116] In the above formula (T-2), k2 is an integer of 0 to 7. When k2 is 1, R a4is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, a nitro group, or a halogen atom. When k2 is 2 to 7, multiple R a4 are the same or different and each is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, a nitro group, or a halogen atom, or a plurality of R a4 are combined with each other and are part of a ring structure having 4 to 20 ring members formed together with the carbon chain to which they are bonded. k3 is an integer of 0 to 6. When k3 is 1, R a5 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, a nitro group, or a halogen atom. When k3 is 2 to 6, multiple R a5 are the same or different and each is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, a nitro group, or a halogen atom, or a plurality of R a5 are combined with each other to form a ring structure having 3 to 20 ring members together with the carbon atom or carbon chain to which they are bonded. r is an integer of 0 to 3. a6 represents a single bond or a divalent organic group having 1 to 20 carbon atoms. t2 is an integer of 0 to 2.

[0117] R a4 and R a5 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, -OR k , -COOR k , -O-CO-R k , -OR kk -COOR k or -R kk -CO-R k is preferred. k R is a monovalent hydrocarbon group having 1 to 10 carbon atoms. kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

[0118] In the above formula (T-3), k4 is an integer of 0 to 5. When k4 is 1, R a7 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, a nitro group, or a halogen atom. When k4 is 2 to 5, multiple R a7are the same or different and each is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, a nitro group, or a halogen atom, or a plurality of R a7 are combined with each other and are part of a ring structure having 4 to 20 ring members formed together with the carbon chain to which they are bonded. k5 is an integer of 0 to 5. When k5 is 1, R a8 is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, a nitro group, or a halogen atom. When k5 is 2 to 5, multiple R a8 are the same or different and each is a monovalent organic group having 1 to 20 carbon atoms, a hydroxyl group, a nitro group, or a halogen atom, or a plurality of R a8 are joined together and together with the carbon chain to which they are attached, they are part of a ring structure having 4 to 20 ring members.

[0119] R a7 and R a8 is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, -OSO2-R k , -SO2-R k , -OR k , -COOR k , -O-CO-R k , -OR kk -COOR k , -R kk -CO-R k , -SR k Alternatively, a ring structure formed by combining two or more of these groups is preferred. k R is a monovalent hydrocarbon group having 1 to 10 carbon atoms. kk is a single bond or a divalent hydrocarbon group having 1 to 10 carbon atoms.

[0120] R a3 , R a4 , R a5 , R a7 and R a8 Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the formula: Examples of the alkyl group include linear alkyl groups such as a methyl group, an ethyl group, an n-propyl group, and an n-butyl group; branched alkyl groups such as an i-propyl group, an i-butyl group, a sec-butyl group, and a t-butyl group; aryl groups such as a phenyl group, a tolyl group, a xylyl group, a mesityl group, and a naphthyl group; and aralkyl groups such as a benzyl group and a phenethyl group.

[0121] R a6 Examples of the divalent organic group represented by the formula (P) include R R Examples of the monovalent organic group having 1 to 20 carbon atoms include those in which one hydrogen atom has been removed from the monovalent organic groups having 1 to 20 carbon atoms exemplified as above.

[0122] Above R a3 , R a4 , R a5 , R a7 and R a8 Examples of the substituent that may substitute a hydrogen atom of the hydrocarbon group represented by the formula (I) include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, a carboxy group, a cyano group, a nitro group, an alkoxy group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, an acyl group, an acyloxy group, etc. Among these, a halogen atom is preferred, and a fluorine atom is more preferred.

[0123] R a3 , R a4 , R a5 , R a7 and R a8 Examples of the alkyl group include an unsubstituted linear or branched monovalent alkyl group, a monovalent fluorinated alkyl group, an unsubstituted monovalent aromatic hydrocarbon group, -OSO2-R k , -SO2-R k -OR k is preferred, a fluorinated alkyl group, an unsubstituted monovalent aromatic hydrocarbon group or an alkoxy group is more preferred, and a fluorinated alkyl group or an alkoxy group is even more preferred.

[0124] In formula (T-1), k1 is preferably 0 to 2, more preferably 0 or 1, and even more preferably 0. In formula (T-2), k2 is preferably 0 to 2, more preferably 0 or 1, and even more preferably 1. In formula (T-2), k3 is preferably 0 to 2, more preferably 0 or 1, and even more preferably 0. In formula (T-3), r is preferably 2 or 3, and more preferably 2. In formula (T-4), t2 is preferably 0 or 1, and even more preferably 1. In formula (T-5), k4 and k5 are preferably 0 to 2, more preferably 0 or 1, and even more preferably 0.

[0125] T + As the cation (T-1) or (T-2), the cation (Z-1) is more preferable, and the triphenylsulfonium cation is further preferable.

[0126] [B] Examples of the acid generator that generates sulfonic acid include the compounds represented by the following formulas (4-1-1) to (4-1-19) (hereinafter also referred to as "compounds (4-1-1) to (4-1-19)"); and examples of the acid generator that generates imidic acid include the compounds represented by the following formulas (4-2-1) to (4-2-3) (hereinafter also referred to as "compounds (4-2-1) to (4-2-3)").

[0127] [ka]

[0128] [ka]

[0129] [ka]

[0130] In the above formulas (4-1-1) to (4-1-19) and (4-2-1) to (4-2-3), T + is a monovalent radiation-sensitive onium cation.

[0131] The acid generator [B] is preferably the compound (4-1), and more preferably the compound (4-1-1), (4-1-3), (4-1-4), (4-1-16), (4-1-17) or (4-1-19).

[0132] When the acid generator [B] is an acid generator [B], the lower limit of the content of the acid generator [B] is preferably 0.1 parts by mass, more preferably 1 part by mass, even more preferably 5 parts by mass, and particularly preferably 10 parts by mass, relative to 100 parts by mass of the polymer [A]. The upper limit of the content is preferably 50 parts by mass, more preferably 40 parts by mass, even more preferably 30 parts by mass, and particularly preferably 25 parts by mass. By setting the content of the acid generator [B] within the above range, the sensitivity and process window can be further improved. The acid generator [B] can contain one type or two or more types.

[0133] <[C] compound> The compound [C] is a compound represented by the following formula (1): The compound [C] acts as an acid diffusion controller in the radiation-sensitive resin composition.

[0134] [ka]

[0135] In the above formula (1), R 1 is a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms. n+ is a radiation-sensitive onium cation having a valence of n, where n is an integer of 1 to 3.

[0136] R 1 Examples of the monovalent organic group having 1 to 30 carbon atoms represented by the formula (P) include R R Examples of the monovalent organic group having 1 to 20 carbon atoms include the same groups as those exemplified above.

[0137] R 1 Specific examples of the organic group include linear or alicyclic hydrocarbon groups having a tertiary carbon atom as a bonding site, such as t-butyl group, 1-methylcyclopentan-1-yl group, 1-ethylcyclopentan-1-yl group, 1-phenylcyclohexan-1-yl group, 2-ethyladamantan-2-yl group, and adamantan-1-yl group (more specifically, linear or alicyclic hydrocarbon groups having a tertiary carbon atom bonded to the oxyoxy atom of a carbonyloxy group); A linear or alicyclic hydrocarbon group having a secondary carbon atom as a bonding site, such as a cyclohexyl group, a norbornyl group, or an i-propyl group (more specifically, a linear or alicyclic hydrocarbon group having a secondary carbon atom bonded to the oxyoxy atom of a carbonyloxy group); A chain hydrocarbon group having a primary carbon atom as a bonding site, such as an ethyl group or a pentyl group (more specifically, a chain hydrocarbon group in which a primary carbon atom is bonded to the oxyoxy atom of a carbonyloxy group); Aromatic hydrocarbon groups such as a phenyl group, a naphthyl group, and a benzyl group; Examples of the fluorinated hydrocarbon groups include a 1,1,1,3,3,3-hexafluoropropan-2-yl group, a 2,2,2-trifluoroethane-1-yl group, a perfluorocyclohexan-1-yl group, and a 2,4,6-trifluorophenyl group.

[0138] R 1 The organic group R preferably has a ring structure. 1 When the organic group has a ring structure, the diffusion of the compound [C] in the resist film is more appropriately suppressed, and as a result, the process window can be further expanded. Examples of the organic group having a ring structure include a substituted or unsubstituted alicyclic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, and the like.

[0139] Also, R 1 The organic group of R is preferably an acid-dissociable group. 1 is an acid dissociable group, R 1is dissociated to generate a carboxyl group, which improves the solubility in the developer, and as a result, the process window can be further expanded. Examples of the organic group that is an acid dissociable group include the groups exemplified above as the linear or alicyclic hydrocarbon group having a tertiary carbon atom as a bonding site (excluding adamantane-1-yl group), and cycloalkene-3-yl groups such as cyclohexene-3-yl group.

[0140] X n+ Examples of the n-valent radiation-sensitive onium cation represented by the formula (1) include a sulfonium cation, a tetrahydrothiophenium cation, an iodonium cation, etc. Among these, the sulfonium cation or the iodonium cation is preferred.

[0141] When n is 1, an example of the sulfonium cation is the cation (T-1) in the acid generator [B]. When n is 1, an example of the iodonium cation is the cation (T-3) in the acid generator [B].

[0142] X n+ As the cation (T-1), a monovalent sulfonium cation is preferable, the cation (T-1) is more preferable, and the triphenylsulfonium cation is even more preferable.

[0143] As n, 1 or 2 is preferable, and 1 is more preferable.

[0144] Examples of the compound [C] include compounds represented by the following formulas (1-1) to (1-9) (hereinafter also referred to as "compounds (1-1) to (1-9)").

[0145] [ka]

[0146] In the above formulas (1-1) to (1-9), (X n+ ) 1 / n has the same meaning as the above formula (1).

[0147] The lower limit of the content of the compound [C] is preferably 0.1 parts by mass, more preferably 0.5 parts by mass, even more preferably 1 part by mass, and particularly preferably 2 parts by mass, relative to 100 parts by mass of the polymer [A].The upper limit of the content is preferably 20 parts by mass, more preferably 15 parts by mass, even more preferably 10 parts by mass, and particularly preferably 7 parts by mass.

[0148] The lower limit of the content of the compound [C] is preferably 1 mol%, more preferably 5 mol%, further preferably 10 mol%, and particularly preferably 15 mol%, relative to 100 mol% of the acid generator [B].The upper limit of the content is preferably 100 mol%, more preferably 50 mol%, further preferably 30 mol%, and particularly preferably 25 mol%.

[0149] By setting the content of the compound [C] within the above range, the sensitivity and the process window can be further improved.

[0150] <Method for synthesizing compound [C]> [C] Compounds such as R 1 The compound can be synthesized by reacting an alcohol represented by -OH with tetrafluorosuccinic anhydride in a solvent such as dichloromethane in the presence of a base such as triethylamine, and then adding a salt such as triphenylsulfonium chloride to the reaction product to perform ion exchange.

[0151] <[D] Solvent> The solvent [D] is not particularly limited as long as it is a solvent that can dissolve or disperse at least the polymer [A], the acid generator [B], the compound [C], and any optional components that are contained as desired.

[0152] Examples of the solvent (D) include alcohol-based solvents, ether-based solvents, ketone-based solvents, amide-based solvents, ester-based solvents, and hydrocarbon-based solvents.

[0153] Examples of alcohol-based solvents include Aliphatic monoalcohol solvents having 1 to 18 carbon atoms, such as 4-methyl-2-pentanol and n-hexanol; Alicyclic monoalcohol solvents having 3 to 18 carbon atoms, such as cyclohexanol; Polyhydric alcohol solvents having 2 to 18 carbon atoms, such as 1,2-propylene glycol; Examples of suitable solvents include partial ether solvents of polyhydric alcohols having 3 to 19 carbon atoms, such as propylene glycol-1-monomethyl ether.

[0154] Examples of ether solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, dibutyl ether, dipentyl ether, diisoamyl ether, dihexyl ether, and diheptyl ether; Cyclic ether solvents such as tetrahydrofuran and tetrahydropyran; Examples of the solvent include aromatic ring-containing ether solvents such as diphenyl ether and anisole.

[0155] Examples of ketone solvents include Chain ketone solvents such as acetone, methyl ethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, diethyl ketone, methyl iso-butyl ketone, 2-heptanone, ethyl n-butyl ketone, methyl n-hexyl ketone, di-iso-butyl ketone, and trimethylnonanone: Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, etc. Examples include 2,4-pentanedione, acetonylacetone, and acetophenone.

[0156] Examples of amide solvents include Cyclic amide solvents such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone; Examples of the solvent include chain amide solvents such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, and N-methylpropionamide.

[0157] Examples of ester solvents include Monocarboxylic acid ester solvents such as n-butyl acetate and ethyl lactate; Polyhydric alcohol carboxylate solvents such as propylene glycol acetate; Polyhydric alcohol partial ether carboxylate solvents such as propylene glycol monomethyl ether acetate; Polycarboxylic acid diester solvents such as diethyl oxalate; Examples of the solvent include carbonate-based solvents such as dimethyl carbonate and diethyl carbonate.

[0158] Examples of the hydrocarbon solvent include Aliphatic hydrocarbon solvents having 5 to 12 carbon atoms, such as n-pentane and n-hexane; Examples of the solvent include aromatic hydrocarbon solvents having 6 to 16 carbon atoms, such as toluene and xylene.

[0159] Among these, alcohol-based solvents and / or ester-based solvents are preferred, polyhydric alcohol partial ether-based solvents and / or polyhydric alcohol partial ether carboxylate-based solvents are more preferred, and propylene glycol-1-monomethyl ether and / or propylene glycol monomethyl ether acetate are even more preferred. [D] The solvent may contain one or more kinds.

[0160] <Other optional ingredients> Examples of other optional components include an acid diffusion controller (excluding those corresponding to the compound [C]), a surfactant, etc. These other optional components may be used alone or in combination of two or more kinds.

[0161] [Acid diffusion controller] The acid diffusion controller controls the diffusion phenomenon in the resist film of the acid generated from the acid generator [B] etc. upon exposure, and has the effect of suppressing undesirable chemical reactions in non-exposed regions. The acid diffusion controller may be contained in the radiation-sensitive resin composition in the form of a free compound (hereinafter, appropriately referred to as an "acid diffusion controller"), in the form of being incorporated as a part of the polymer [A] etc., or in both of these forms.

[0162] Examples of the acid diffusion controller include nitrogen-containing compounds, photodegradable bases (excluding those corresponding to the [C] compounds), etc. Photodegradable bases are compounds that decompose upon exposure to light and thus lose basicity.

[0163] Examples of the nitrogen-containing compound include compounds having one nitrogen atom, such as monoalkylamines, compounds having two nitrogen atoms, such as ethylenediamine, compounds having three or more nitrogen atoms, such as polyethyleneimine, amide group-containing compounds, such as N,N-dimethylacetamide, urea compounds, such as 1,1,3,3-tetramethylurea, and nitrogen-containing heterocyclic compounds, such as N-(undecylcarbonyloxyethyl)morpholine and Nt-butoxycarbonyl-4-hydroxypiperidine.

[0164] Examples of photodegradable bases include triphenylsulfonium salicylate, triphenylsulfonium 10-camphorsulfonate, triphenylsulfonium adamantan-1-yl oxalate, triphenylsulfonium 2,3,4,5-tetrafluoro-6-hydroxybenzoate, triphenylsulfonium 5,6-di(cyclohexyloxycarbonyl)norbornane-2-sulfonate, triphenylsulfonium 1,2-di(norbornane-2,6-lactone-5-yloxycarbonyl)ethane-1-sulfonate, triphenylsulfonium 3-(adamantan-1-yl)-3-hydroxy-2,2-difluoropropionate, and triphenylsulfonium 4-cyclohexyloxycarbonyl-2,2,3,3,4,4-hexafluorobutyrate.

[0165] When the radiation-sensitive resin composition contains an acid diffusion controller, the lower limit of the content of the acid diffusion controller is preferably 0.1 parts by mass, more preferably 1 part by mass, and even more preferably 2 parts by mass, relative to 100 parts by mass of the polymer [A]. The upper limit of the content is preferably 20 parts by mass, more preferably 10 parts by mass, and even more preferably 7 parts by mass.

[0166] When the radiation-sensitive resin composition contains an acid diffusion controller, the lower limit of the content of the acid diffusion controller is preferably 1 mol%, more preferably 5 mol%, further preferably 10 mol%, and particularly preferably 15 mol%, based on 100 mol% of the acid generator [B]. The upper limit of the content is preferably 100 mol%, more preferably 50 mol%, further preferably 30 mol%, and particularly preferably 25 mol%. The radiation-sensitive resin composition may contain one or more acid diffusion controllers.

[0167] [Surfactants] The surfactant has the effect of improving coatability, striation, developability, etc. Examples of the surfactant include nonionic surfactants such as polyoxyethylene lauryl ether. When the radiation-sensitive resin composition contains a surfactant, the upper limit of the surfactant content is preferably 2 parts by mass per 100 parts by mass of the polymer [A].

[0168] <Method for preparing radiation-sensitive resin composition> The radiation-sensitive resin composition can be prepared, for example, by mixing the polymer [A], the acid generator [B], the compound [C], the solvent [D], and other optional components as necessary in a predetermined ratio, and preferably filtering the resulting mixture through a filter having a pore size of about 0.2 μm.

[0169] <Method of forming resist pattern> The method for forming a resist pattern includes a step of directly or indirectly applying a radiation-sensitive resin composition to a substrate (hereinafter also referred to as a "coating step"), a step of exposing the resist film formed by the coating step (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"). In the method for forming a resist pattern, the above-mentioned radiation-sensitive resin composition is used as the radiation-sensitive resin composition.

[0170] According to the above-mentioned method for forming a resist pattern, since the radiation-sensitive resin composition is used, a resist pattern can be formed with high sensitivity and a wide process window. Each step will be described below.

[0171] [Coating process] In this step, the radiation-sensitive resin composition is applied directly or indirectly to a substrate. This forms a resist film. Examples of the substrate on which the resist film is formed include conventionally known substrates such as silicon wafers, silicon dioxide, and aluminum-coated wafers. In addition, examples of indirectly applying the radiation-sensitive resin composition to a substrate include applying the radiation-sensitive resin composition to an underlayer film such as an anti-reflection film formed on a substrate. Examples of such anti-reflection films include organic or inorganic anti-reflection films disclosed in JP-B-6-12452 and JP-A-59-93448. Examples of the application method include spin coating, casting coating, and roll coating. After application, pre-baking (PB) may be performed as necessary to volatilize the solvent in the coating. The lower limit of the PB temperature is preferably 60° C., and more preferably 80° C. The upper limit of the PB temperature is preferably 160° C., and more preferably 140° C. The lower limit of the PB time is preferably 5 seconds, more preferably 10 seconds. The upper limit of the PB time is preferably 600 seconds, more preferably 300 seconds. The lower limit of the average thickness of the resist film formed is preferably 10 nm, more preferably 20 nm. The upper limit of the average thickness is preferably 1,000 nm, more preferably 500 nm. The average thickness of the resist film is a value measured using a spectroscopic ellipsometer (JAWOOLLAM's "M2000D").

[0172] [Exposure process] In this step, the resist film formed in the coating step is exposed to light. This exposure is performed by irradiating the resist film through a photomask (or through an immersion medium such as water, in some cases). Examples of the exposure light include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light (EUV), X-rays, and gamma rays; charged particle beams such as electron beams and alpha rays, depending on the line width of the desired pattern. Among these, far ultraviolet light, EUV, or electron beams are preferred, ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), EUV, or electron beams are more preferred, and EUV or electron beams are even more preferred.

[0173] After the exposure, it is preferable to perform post-exposure baking (PEB) to promote dissociation of the acid-dissociable group of the polymer (A) or the like by the acid generated from the acid generator (B) or the like by exposure in the exposed portion of the resist film. This PEB can increase the difference in solubility in the developer between the exposed portion and the unexposed portion. The lower limit of the PEB temperature is preferably 50°C, more preferably 80°C. The upper limit of the PEB temperature is preferably 180°C, more preferably 140°C. The lower limit of the PEB time is preferably 5 seconds, more preferably 10 seconds. The upper limit of the PEB time is preferably 600 seconds, more preferably 300 seconds.

[0174] [Development process] In this step, the exposed resist film is developed. This allows a desired resist pattern to be formed. After development, the resist film is generally washed with a rinse liquid such as water or alcohol, and then dried. The developing method in the developing step may be either alkaline development or organic solvent development. Of these, alkaline development is preferred.

[0175] In the case of alkaline development, examples of the developer used for development include an alkaline aqueous solution in which at least one of alkaline compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia water, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, and 1,5-diazabicyclo-[4.3.0]-5-nonene is dissolved. Among these, a TMAH aqueous solution is preferred, and a 2.38 mass % TMAH aqueous solution is more preferred.

[0176] In the case of organic solvent development, examples of the developer include organic solvents such as hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, and alcohol solvents, and solvents containing the above organic solvents. Examples of the organic solvent include one or more of the solvents listed as the solvent [D] of the radiation-sensitive resin composition. Among these, ester solvents or ketone solvents are preferred. As the ester solvent, acetate solvents are preferred, and n-butyl acetate is more preferred. As the ketone solvent, chain ketones are preferred, and 2-heptanone is more preferred. The lower limit of the content of the organic solvent in the developer is preferably 80% by mass, more preferably 90% by mass, even more preferably 95% by mass, and particularly preferably 99% by mass. Examples of components other than the organic solvent in the developer include water and silicone oil.

[0177] Development methods include, for example, a method in which the substrate is immersed in a tank filled with developer for a certain period of time (dip method), a method in which the developer is piled up on the substrate surface by surface tension and left to stand for a certain period of time (paddle method), a method in which the developer is sprayed onto the substrate surface (spray method), and a method in which the developer is continuously dispensed by scanning a developer dispensing nozzle at a constant speed over a substrate rotating at a constant speed (dynamic dispense method).

[0178] <Compound> The compound is represented by the following formula (1): The compound can be suitably used as an acid diffusion controller in the radiation-sensitive resin composition.

[0179] [ka]

[0180] In the above formula (1), R 1 is a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms. n+ is an n-valent cation, where n is an integer of 1 to 3.

[0181] X n+Examples of n-valent cations represented by the formula Examples of monovalent cations include monovalent onium cations and alkali metal cations. Examples of divalent cations include divalent onium cations and alkaline earth metal cations. Examples of the trivalent cation include a trivalent onium cation and a trivalent metal cation.

[0182] The onium cation may be radiation sensitive or may not be radiation sensitive. The radiation sensitive onium cation is, for example, T + Examples of the monovalent radiation-sensitive onium cation include the sulfonium cation, iodonium cation, and tetrahydrothiophenium cation exemplified above. The divalent and trivalent cations include both cations containing a cationic moiety with a 2+ or 3+ charge, and cations containing two or three cationic moieties with a 1+ charge.

[0183] X in the above formula (1) n+ The cation is preferably an onium cation. This onium cation is preferably radiation sensitive. EXAMPLES

[0184] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Physical properties in the examples were measured as follows.

[0185] [Weight average molecular weight (Mw), number average molecular weight (Mn) and dispersity (Mw / Mn)] Measurements were performed by gel permeation chromatography (GPC) using Tosoh Corporation's GPC columns (G2000HXL: 2, G3000HXL: 1, G4000HXL: 1) under the following analytical conditions: flow rate: 1.0 mL / min, elution solvent: tetrahydrofuran, sample concentration: 1.0 mass%, sample injection amount: 100 μL, column temperature: 40° C., detector: differential refractometer, with monodisperse polystyrene as the standard. The dispersity (Mw / Mn) was calculated from the measurement results of Mw and Mn.

[0186] [Content of each structural unit of the polymer] The content ratio of each structural unit of the polymer was measured using a nuclear magnetic resonance apparatus (JNM-Delta400 manufactured by JEOL Ltd.). 13 This was analyzed by C-NMR.

[0187] <Synthesis of polymer [A]> The monomers used in the synthesis of the polymer [A] are shown below. In the following synthesis examples, unless otherwise specified, parts by mass refer to a value when the total mass of the monomers used is taken as 100 parts by mass, and mol % refers to a value when the total number of moles of the monomers used is taken as 100 mol %.

[0188] [ka]

[0189] [Synthesis Example 1] (Synthesis of Polymer (A-1)) The above monomer (M-3) and monomer (M-1) were dissolved in propylene glycol-1-monomethyl ether (200 parts by mass) so that the molar ratio was 60 / 40. Next, azobisisobutyronitrile (AIBN) (6 mol%) was added as a radical polymerization initiator to prepare a monomer solution. Meanwhile, propylene glycol-1-monomethyl ether (100 parts by mass) was added to an empty reaction vessel and heated to 85°C while stirring. Next, the above prepared monomer solution was dropped over 3 hours, and then heated at 85°C for another 3 hours, and the polymerization reaction was carried out for a total of 6 hours. After the polymerization reaction was completed, the polymerization reaction liquid was cooled to room temperature. The cooled polymerization reaction liquid was poured into hexane (500 parts by mass relative to 100 parts by mass of the polymerization reaction liquid), and the precipitated white powder was filtered off. The filtered white powder was washed twice with hexane (100 parts by mass relative to 100 parts by mass of the polymerization reaction liquid), filtered off, and dissolved in propylene glycol-1-monomethyl ether (300 parts by mass). Next, methanol (500 parts by mass), triethylamine (50 parts by mass), and ultrapure water (10 parts by mass) were added, and the hydrolysis reaction was carried out at 70°C for 6 hours while stirring. After the reaction was completed, the remaining solvent was distilled off, and the obtained solid was dissolved in acetone (100 parts by mass). The obtained solution was dropped into water (500 parts by mass) to coagulate the polymer, and the obtained solid was filtered off. It was dried at 50°C for 12 hours to synthesize a white powdery polymer (A-1). The Mw of the polymer (A-1) was 5,700, and the Mw / Mn was 1.61. 13 As a result of C-NMR analysis, the contents of the structural units derived from (M-3) and (M-1) were 59.1 mol % and 40.9 mol %, respectively.

[0190] [Synthesis Examples 2-9] Polymers (A-2) to (A-9) were synthesized in the same manner as in Synthesis Example 1, except that the types and amounts of each monomer shown in Table 1 were used. In Table 1, "-" indicates that the corresponding monomer was not used.

[0191] [Table 1]

[0192] <Synthesis of [C] Compound> [Example 1] (Synthesis of compound (Z-1)) Compound (Z-1) was synthesized according to the following reaction scheme.

[0193] [ka]

[0194] A reaction vessel was charged with 29 mmol of the compound represented by the above formula (ppz-1) (cyclohexanol), 29 mmol of triethylamine (NEt3), and 100 g of dichloromethane. After stirring at 0°C, 14.5 mmol of tetrafluorosuccinic anhydride was added dropwise. After stirring at room temperature for 12 hours, 100 g of water and 16 mmol of triphenylsulfonium chloride (TPS-Cl) were added to the compound represented by the above formula (pz-1) (triethylammonium 2-(cyclohexylcarbonyl)-1,1,2,2-tetrafluoro-propionate). After stirring at room temperature for 2 hours, the organic layer was separated. The obtained organic layer was washed with water. After drying with anhydrous sodium sulfate, the solvent was distilled off, and recrystallization was performed to obtain compound (Z-1).

[0195] [Examples 2 to 9] (Synthesis of Compounds (Z-2) to (Z-9)) By appropriately selecting precursors and selecting the same recipe as in Example 1, compounds represented by the following formulas (Z-2) to (Z-9) were synthesized.

[0196] [ka]

[0197] <Preparation of Radiation-Sensitive Resin Composition> The acid generator [B] and the solvent [D] used in the preparation of the radiation-sensitive resin composition and the acid diffusion controller [E] used in the preparation of the radiation-sensitive resin composition of the comparative example are shown below.

[0198] [[B] Acid generator] B-1 to B-6: Compounds represented by the following formulas (B-1) to (B-6)

[0199] [ka]

[0200] [[D] Solvent] D-1: Propylene glycol monomethyl ether acetate D-2: Propylene glycol-1-monomethyl ether

[0201] [[E] Acid diffusion control agent] E-1 to E-3: Compounds represented by the following formulas (E-1) to (E-3)

[0202] [ka]

[0203] [Example 10] A radiation-sensitive resin composition (R-1) was prepared by mixing 100 parts by mass of (A-1) as a polymer [A] and 20 parts by mass of (B-1) as an acid generator, [B] 20 mol % of (Z-1) as a compound [C] relative to 100 mol % of (B-1), and 4,800 parts by mass of (D-1) and 2,000 parts by mass of (D-2) as a solvent [D]. The resulting mixture was filtered through a membrane filter having a pore size of 0.2 μm.

[0204] [Examples 11 to 31 and Comparative Examples 1 to 3] Radiation-sensitive resin compositions (R-2) to (R-22) and (CR-1) to (CR-3) were prepared in the same manner as in Example 10, except that the types and amounts of each component shown in Table 2 below were used.

[0205] [Table 2]

[0206] <Formation of Resist Pattern> The radiation-sensitive resin composition prepared above was applied to the surface of a 12-inch silicon wafer on which an underlayer film ("AL412" from Brewer Science) with an average thickness of 20 nm was formed, using a spin coater ("CLEAN TRACK ACT12" from Tokyo Electron Co., Ltd.), and PB was performed at 130°C for 60 seconds, followed by cooling at 23°C for 30 seconds to form a resist film with an average thickness of 50 nm. Next, this resist film was irradiated with EUV light using an EUV exposure machine ("NXE3300" from ASML, NA = 0.33, illumination conditions: Conventional s = 0.89, mask imecDEFECT32FFR02). After irradiation, the resist film was subjected to PEB at 130°C for 60 seconds. Next, it was developed at 23°C for 30 seconds using a 2.38 mass% TMAH aqueous solution to form a positive 32 nm line and space pattern.

[0207] <Evaluation> For each resist pattern formed as above, the sensitivity and process window of each radiation-sensitive resin composition were evaluated according to the following method. The resist patterns were measured using a scanning electron microscope ("CG-4100" manufactured by Hitachi High-Technologies Corporation). The evaluation results are shown in Table 3 below.

[0208] [sensitivity] In forming the resist pattern, the exposure dose for forming a 32 nm line and space pattern was defined as the optimum exposure dose, and this optimum exposure dose was defined as the sensitivity (mJ / cm 2 The sensitivity was 30 mJ / cm 2 The following are considered "good": 30mJ / cm 2 If it exceeds this, it can be rated as "poor".

[0209] [Process Window] Patterns were formed from low to high exposure doses using a mask that forms 32 nm lines and spaces (1L / 1S). Generally, defects such as connections between patterns are seen on the low exposure dose side, while defects such as pattern collapse are seen on the high exposure dose side. The difference between the upper and lower limits of the resist dimensions where these defects are not seen is defined as the "CD (Critical Dimension) margin" and is used as an index of the process window. The larger the CD margin (nm), the wider the process window is considered to be. A CD margin of 30 nm or more can be evaluated as "good," and one less than 30 nm can be evaluated as "poor."

[0210] [Table 3]

[0211] As is clear from the results in Table 3, the radiation-sensitive resin compositions of the Examples all had better sensitivity and CD margin than the radiation-sensitive resin compositions of the Comparative Examples. [Industrial Applicability]

[0212] According to the radiation-sensitive resin composition and the method for forming a resist pattern of the present invention, a resist pattern can be formed with excellent sensitivity and a wide process window. The compound of the present invention can be suitably used as a component of the radiation-sensitive resin composition. Therefore, they can be suitably used in the processing of semiconductor devices, which are expected to become increasingly finer in the future.

Claims

1. A compound represented by the following formula (1): 【Chemistry 1】 (In formula (1), R １ is a hydrogen atom or a monovalent organic group having 1 to 30 carbon atoms. ｎ＋ is an n-valent cation, where n is an integer from 1 to 3.

2. X in the above formula (1) ｎ＋ 2. The compound according to claim 1, wherein the cation is an onium cation.

3. Above X ｎ＋ 3. The compound of claim 2, wherein the onium cation is radiation sensitive.

4. X in the above formula (1) ｎ＋ The compound of claim 3, wherein is a sulfonium cation, an iodonium cation, or a combination thereof.

5. R in the above formula (1) １ is an organic group, which is a linear or alicyclic hydrocarbon group having a bonding site at a tertiary carbon atom, a linear or alicyclic hydrocarbon group having a bonding site at a secondary carbon atom, a linear hydrocarbon group having a bonding site at a primary carbon atom, an aromatic hydrocarbon group, or a fluorinated hydrocarbon group.

6. R in the above formula (1) １ The compound according to any one of claims 1 to 5, wherein: is an organic group having a ring structure.

7. R in the above formula (1) １ The compound according to any one of claims 1 to 6, wherein: is an organic group, and this organic group is an acid-dissociable group.

8. The compound according to any one of claims 1 to 7, wherein n in the above formula (1) is 1.

9. The compound according to any one of claims 1 to 8, represented by the following formulas (1-1) to (1-9): 【Chemistry 2】 (In formulas (1-1) to (1-9), X ｎ＋ and n are the same as those in formula (1) above.