Radiation-sensitive composition, pattern formation method, and compound

Abstract

The purpose of the present invention is to provide a radiation-sensitive composition with which it is possible to form a resist film that can exhibit sufficient levels of sensitivity, exposure latitude, focus depth, pattern rectangularity, pattern circularity, CDU, LWR, and defect suppression, a pattern formation method, and a compound. This radiation-sensitive composition contains: a nonionic radiation-sensitive acid generator having a partial structure represented by formula (a-1) and a sulfonyl group; a polymer; and a solvent.　

Description

Radiation-sensitive composition, pattern-forming method, and compound

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

[0002] Photolithography, which uses resist compositions, is employed to form fine circuits in semiconductor devices. A typical procedure involves, for example, generating acid by irradiating a resist composition film with radiation through a mask pattern. This acid then acts as a catalyst, creating a difference in the solubility of the polymer in alkaline or organic solvent-based developers between the exposed and unexposed areas, thereby forming a resist pattern on the substrate.

[0003] The above-mentioned photolithography techniques utilize radiation such as KrF and ArF excimer lasers, or combine this radiation with liquid immersion lithography to advance pattern miniaturization. As a next-generation technology, efforts are being made to utilize even shorter wavelength radiation such as electron beams, X-rays, and EUV (extreme ultraviolet).

[0004] Currently, with the increasing integration of LSIs and the advancement of communication speeds, there is a growing demand for increased memory capacity, and further miniaturization of patterns is rapidly progressing. However, electron beam and EUV lithography, while aiming to form fine patterns of tens of nanometers, still faces many challenges such as low productivity, and there are limitations to microfabrication technology. In response to this, in addition to miniaturization, development is underway on three-dimensional structured devices that aim to increase memory capacity by stacking cells.

[0005] Furthermore, a wide variety of acid generator components have been proposed for use in chemically amplified resist compositions. For example, onium salt-based acid generators such as iodonium salts and sulfonium salts, oxime sulfonate-based acid generators, diazomethane-based acid generators, nitrobenzyl sulfonate-based acid generators, iminosulfonate-based acid generators, and disulfone-based acid generators are known (Japanese Patent Publication No. 5965855 and Japanese Patent Publication No. 3991223).

[0006] Patent No. 5965855 Patent No. 3991223

[0007] The manufacturing of the above-mentioned three-dimensional structure device involves a process of forming a thick resist film on the surface of the workpiece, with a higher film thickness than conventional methods (for example, a film thickness of 1 μm or more), to form a resist pattern, and then performing etching. When a chemically amplified resist composition is used in this process, the thicker the resist film, the more difficult it becomes to maintain sensitivity during exposure, resulting in a decrease in resolution during development and making it difficult to obtain the desired roughness and defect performance. Furthermore, as the thickness of the resist film increases, the transmittance to the bottom decreases, leading to a deterioration of the resist pattern shape.

[0008] In deploying the above-mentioned next-generation technologies, the resist composition is required to have resist performance equivalent to or better than conventional resists in terms of sensitivity, exposure margin, depth of field, pattern rectangularity, pattern circularity, CDU, LWR, and defect suppression during pattern formation.

[0009] The present invention aims to provide a radiation-sensitive composition, a pattern-forming method, and a compound capable of forming a resist film that exhibits sufficient levels of sensitivity, exposure margin, depth of field, pattern rectangularity, pattern circularity, CDU, LWR, and defect suppression.

[0010] The inventors of this invention conducted extensive research to solve this problem and, as a result, found that the above objective can be achieved by adopting the following configuration, thus completing the present invention.

[0011] In other words, the present invention relates in one embodiment to a radiation-sensitive composition comprising a nonionic radiation-sensitive acid generator having a substructure represented by the following formula (a-1) and a sulfonyl group, a polymer, and a solvent. (In formula (a-1), R Ｘ R is a hydrogen atom or a monovalent organic group having one or more carbon atoms. L is a single bond or a divalent linking group. ｆ１ and R ｆ２ These are, independently, a hydrogen atom, -CN, and -NO. ２ -F, -CF ２ R ｔ１ , -SO ２ R ｔ２ ,-CORｔ３ or -CF ２ R ｔ１ , -SO ２ R ｔ２ , -COR ｔ３ or -CF ３ is a monovalent organic group (a) having 1 to 20 carbon atoms other than the above. R ｔ１ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ｔ２ and R ｔ３ are each independently a monovalent organic group having 1 to 20 carbon atoms. R ｆ１ and R ｆ２ when a plurality of R ｆ１ and R ｆ２ are each the same or different. n is an integer of 1 to 5. * is a bonding hand to the sulfur atom of the sulfonyl group. Provided that at least one of R ｆ１ and R ｆ２ is -CN, -NO ２ , -F, -CF ２ R ｔ１ , -SO ２ R ｔ２ , or -COR ｔ３ , and when one or more R ｆ１ is -F, R ｆ１ bonded to the carbon atom to which R ｆ２ being -F is bonded is a group other than -F, and when at least one of R ｆ１ and R ｆ２ is -CN or -SO ２ R ｔ２ , R Ｘ is a hydrogen atom or a monovalent organic group having 1 or more carbon atoms, and when R ｆ１ and R ｆ２ are groups other than -CN or -SO ２ R ｔ２ , R Ｘ is a monovalent organic group having 1 or more carbon atoms.)

[0012] By using the above composition, the radiation-sensitive composition can form a resist film that exhibits sufficient levels of sensitivity, exposure margin, depth of field, pattern rectangularity, pattern circularity, CDU, LWR, and defect suppression. The reason for this is presumed to be as follows, although it is not bound by any theory.

[0013] Radiation-sensitive acid generators with an ionic structure have a problem of low dispersibility because they are highly polar components that can aggregate with each other. The radiation-sensitive acid generator contained in this composition is nonionic and has a low fluorine content, so it has high dispersibility and is uniformly dispersed in the resist film. Furthermore, because it has electron-withdrawing groups near the generated acid, it can increase the acidity of the generated acid despite the low fluorine content. Due to the low fluorine content in the compound, it also has excellent solubility in alkaline developers. As a result, it is possible to achieve both suppression of development defects caused by aggregation and various roughness performance while maintaining high sensitivity. In addition, because the nonionic type of radiation-sensitive acid generator has high transparency to radiation due to its structure, the amount added to the resist can be increased. This makes it possible to increase the acid generation points while allowing sufficient light to penetrate to the bottom of the resist film, and it is possible to improve the pattern shape, which has been a problem in thick-film resists in particular. In other words, it is presumed that the radiation-sensitive acid generator contained in this composition exhibits the above-mentioned resist performance by possessing a combination of properties such as high dispersibility in the film, high acidity of the generated acid, high solubility in the developer, and high transparency to radiation.

[0014] In another embodiment, the present invention relates to a pattern forming method comprising the steps of: applying the radiation-sensitive composition directly or indirectly to a substrate to form a resist film; exposing the resist film to light; and developing the exposed resist film with a developer.

[0015] This pattern formation method uses the above-mentioned radiation-sensitive composition, which is capable of forming a resist film with excellent sensitivity, exposure margin, depth of field, pattern rectangularity, pattern circularity, CDU, LWR, and defect suppression, thus enabling the efficient formation of high-quality resist patterns.

[0016] In another embodiment, the present invention relates to a compound represented by any one of the following formulas: (1), (2'), and (3). (In equations (1), (2'), and (3), R １ and R ２ Each of these is independently either a cyano group, a nitro group, a monovalent organic group having 1 to 20 carbon atoms, or R １ and R ２ These atoms are combined with each other and, together with the atoms they bond to, form a cyclic structure. ３ R is a monovalent organic group having 1 to 20 carbon atoms. ａ This is a group represented by the following formula (a-1). (In formula (a-1), R Ｘ R is a hydrogen atom or a monovalent organic group having one or more carbon atoms. L is a single bond or a divalent linking group. ｆ１ and R ｆ２ These are, independently, a hydrogen atom, -CN, and -NO. ２ -F, -CF ２ R ｔ１ , -SO ２ R ｔ２ ,-COR ｔ３ , or -CF ２ R ｔ１ , -SO ２ R ｔ２ ,-COR ｔ３ Or -CF ３ (a) is a monovalent organic group with 1 to 20 carbon atoms other than R. ｔ１ R is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. ｔ２ and R ｔ３ Each of these is independently a monovalent organic group having 1 to 20 carbon atoms. ｆ１ and R ｆ２ If multiple R ｆ１ and R ｆ２ These are either the same or different. n is an integer from 1 to 5. * represents a bond with a sulfur atom in formula (1) or formula (3). However, R ｆ１ and R ｆ２ At least one of them is -CN, -NO ２ -F, -CF ２ Rｔ１ , -SO ２ R ｔ２ , or -COR ｔ３ , and when one or more R ｆ１ is -F, the R ｆ１ that is bonded to the carbon atom to which R that is -F is bonded ｆ２ is a group other than -F, and R ｆ１ and R ｆ２ at least one of which is -CN or -SO ２ R ｔ２ , R Ｘ is a hydrogen atom or a monovalent organic group having 1 or more carbon atoms, and when R ｆ１ and R ｆ２ are groups other than -CN and -SO ２ R ｔ２ , R Ｘ is a monovalent organic group having 1 or more carbon atoms.) R ａ１ is a group represented by the following formula (a-11). (In formula (a-11), R Ｘ１ is a monovalent organic group having 1 or more carbon atoms. L, R ｆ１ , R ｆ２ and n have the same definitions as in the above formula (a-1). Provided that at least one of R ｆ１ and R ｆ２ is -CN, -NO ２ , -F, -CF ２ R ｔ１ , -SO ２ R ｔ２ , or -COR ｔ３ , and when one or more R ｆ１ is -F, the R ｆ１ that is bonded to the carbon atom to which R that is -F is bonded ｆ２ is a group other than -F.))

[0017] The radiation-sensitive composition containing the compound can form a resist film that exhibits sufficient levels of sensitivity, exposure margin, depth of focus, pattern rectangularity, pattern circularity, CDU, LWR, and defect suppression property.

[0018] In this specification, "organic group" means a group containing at least one carbon atom. However, cyano groups, carboxyl groups, formyl groups, carbonyl groups, etc., which can function or be characterized groups on their own as organic groups are excluded. In this specification, "hydrocarbon group" means a group consisting only of carbon and hydrogen atoms, such as a chain hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, but "substituted hydrocarbon group" means a group in which one or more hydrogen atoms of the hydrocarbon group are substituted with a heteroatom-containing group.

[0019] The embodiments of the present invention will be described in detail below, but the present invention is not limited to these embodiments. A preferred combination of embodiments is also preferable.

[0020] <<Radiation-sensitive composition>> The radiation-sensitive composition according to this embodiment (hereinafter also simply referred to as "the composition") contains a nonionic radiation-sensitive acid generator (A) having a partial structure represented by the above formula (a-1) and a sulfonyl group, a polymer (B), and a solvent (E). The above composition may contain other optional components as long as they do not impair the effects of the present invention.

[0021] <Radiation-sensitive acid generator (A)> The nonionic radiation-sensitive acid generator (A) has a substructure represented by the following formula (a-1) (hereinafter also referred to as substructure (a-1)) and a sulfonyl group. Here, a nonionic radiation-sensitive acid generator is a radiation-sensitive acid generator that does not contain an onium salt structure consisting of an anion and an onium cation, and is different from ionic radiation-sensitive acid generators represented by onium salts, etc. (In formula (a-1), R Ｘ R is a hydrogen atom or a monovalent organic group having one or more carbon atoms. L is a single bond or a divalent linking group. ｆ１ and R ｆ２ These are, independently, a hydrogen atom, -CN, and -NO. ２ -F, -CF ２ R ｔ１ , -SO ２ R ｔ２ ,-COR ｔ３ , or -CF ２ R ｔ１ , -SO ２ Rｔ２ ,-COR ｔ３ Or -CF ３ (a) is a monovalent organic group with 1 to 20 carbon atoms other than R. ｔ１ R is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. ｔ２ and R ｔ３ Each of these is independently a monovalent organic group having 1 to 20 carbon atoms. ｆ１ and R ｆ２ If multiple R ｆ１ and R ｆ２ Each of them may be the same or different. n is an integer from 1 to 5. * represents the bond between the sulfonyl group and the sulfur atom. However, R ｆ１ and R ｆ２ At least one of them is -CN, -NO ２ -F, -CF ２ R ｔ１ , -SO ２ R ｔ２ , or -COR ｔ３ and one or more R ｆ１ If R is -F, then R is -F. ｆ１ R bonded to the carbon atom to which it is attached. ｆ２ is a group other than -F, and R ｆ１ and R ｆ２ At least one of them is -CN or -SO ２ R ｔ２ If R Ｘ is a hydrogen atom, or a monovalent organic group having one or more carbon atoms, R ｆ１ and R ｆ２ However, -CN or -SO ２ R ｔ２ For groups other than R Ｘ (This refers to a monovalent organic group having one or more carbon atoms.)

[0022] The overall structure of the radiation-sensitive acid generator (A) consists of a partial structure (a-1) and a sulfonyl group (-SO ２ It is not particularly limited as long as it includes -). Furthermore, the radiation-sensitive acid generator (A) only needs to have one of the substructures (a-1), it may have two or more, but it is preferable to have one or two.

[0023] The above R ＸThe monovalent organic group represented by is preferably a monovalent organic group having 1 to 20 carbon atoms. Examples of a monovalent organic group having 1 to 20 carbon atoms include a monovalent hydrocarbon group having 1 to 20 carbon atoms, a group (a) having a divalent heteroatom-containing group between carbon atoms (between two adjacent or non-adjacent carbon atoms) or at the end of the hydrocarbon group, a group in which some or all of the hydrogen atoms of the hydrocarbon group or group (a) are replaced with a monovalent heteroatom-containing group, or combinations thereof.

[0024] Examples of monovalent hydrocarbon groups having 1 to 20 carbon atoms include monovalent chain hydrocarbon groups having 1 to 20 carbon atoms, monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms, monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms, or combinations thereof.

[0025] Examples of monovalent chain hydrocarbon groups having 1 to 20 carbon atoms include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, and t-butyl groups; alkenyl groups such as ethenyl, propenyl, and butenyl groups; and alkynyl groups such as ethynyl, propynyl, and butynyl groups.

[0026] Examples of monovalent alicyclic hydrocarbon groups having 3 to 20 carbon atoms include cycloalkyl groups such as cyclopentyl and cyclohexyl groups; cycloalkenyl groups such as cyclopropenyl, cyclopentenyl, and cyclohexenyl groups; bridged ring saturated hydrocarbon groups such as norbornyl, adamantyl, and tricyclodecyl groups; and bridged ring unsaturated hydrocarbon groups such as norbornyl and tricyclodecenyl groups.

[0027] Examples of monovalent aromatic hydrocarbon groups having 6 to 20 carbon atoms include aryl groups such as phenyl, tolyl, xyl, naphthyl, and anthryl groups, and aralkyl groups such as benzyl, phenethyl, naphthylmethyl, and anthrylmethyl groups.

[0028] Examples of heteroatoms constituting a divalent or monovalent heteroatom-containing group include oxygen, nitrogen, sulfur, phosphorus, silicon, and halogen atoms. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms.

[0029] Examples of divalent heteroatom-containing groups include -CO-, -CS-, -NR'-, -O-, -S-, combinations thereof, and oxo groups (=O). R' is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.

[0030] Examples of monovalent heteroatom-containing groups include hydroxyl groups, carboxyl groups, sulfanyl groups, cyano groups, nitro groups, and halogen atoms.

[0031] The above R Ｘ Preferably, the group is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and more preferably, a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms or a group containing a lactone structure.

[0032] Examples of the divalent linking group represented by L above include *-COO-, *-OCO-, or -CO- (where * is R Ｘ It is preferable that it be a side joint.

[0033] The above R ｆ１ and R ｆ２ As a monovalent organic group (a) having 1 to 20 carbon atoms represented by the above R Ｘ Examples of monovalent organic groups represented by -CF can be given. ２ R ｔ１ , -SO ２ R ｔ２ ,-COR ｔ３ , -CF ３ Excluding.

[0034] R ｔ１ , R ｔ２ and R ｔ３ As a monovalent organic group having 1 to 20 carbon atoms represented by the above R Ｘ Examples of monovalent organic groups represented by R include: ｔ１ A hydrogen atom is preferred, R ｔ２ The organic group having 1 to 6 carbon atoms is preferred, Rｔ３ The organic group having 1 to 6 carbon atoms is preferred.

[0035] R ｆ１ and R ｆ２ At least one of them is -CN, -NO ２ -F, -CF ２ R ｔ１ , -SO ２ R ｔ２ , or -COR ｔ３ That is. Also, R ｆ１ and R ｆ２ At least one of them is -CN, -SO ２ R ｔ２ It is preferable that one or more R ｆ１ If R is -F, then R is -F. ｆ１ R bonded to the carbon atom to which it is attached. ｆ２ is a group other than -F (i.e., -CF) ２ (- Does not result in). Having these substituents is preferable because it improves solubility in the developer and improves pattern formation compared to conventional radiation-sensitive acid generators.

[0036] Also, R ｆ１ and R ｆ２ At least one of them is -CN or -SO ２ R ｔ２ If R Ｘ is a hydrogen atom, or a monovalent organic group having one or more carbon atoms, R ｆ１ and R ｆ２ However, -CN or -SO ２ R ｔ２ For groups other than R Ｘ R is a monovalent organic group having one or more carbon atoms. Ｘ When is a hydrogen atom, the substructure (a-1) is preferably the structure shown in the following formula (a-1-1) or (a-1-2) (that is, in the above formula (a-1), L is a single bond, n is 1, and R ｆ１ -CN or -SO ２ R ｔ２ (That is the case.) (In the above formulas (a-1-1) and (a-1-2), R ｆ２ , R ｔ２ And * are equivalent to the above formula (a-1).

[0037] n is an integer between 1 and 5, preferably between 1 and 3, and more preferably 1 or 2.

[0038] The radiation-sensitive acid generator (A) is preferably one or more compounds selected from the group consisting of compounds represented by the following formula (1), compounds represented by the following formula (2), and compounds represented by the following formula (3).

[0039] (The compound represented by formula (1)) (In formula (1), R １ and R ２ Each of these is independently either a cyano group, a nitro group, a monovalent organic group having 1 to 20 carbon atoms, or R １ and R ２ These atoms are combined with each other and, together with the atoms they bond to, form a cyclic structure. ａ This is a substructure represented by the above formula (a-1).

[0040] R １ and R ２ As a monovalent organic group having 1 to 20 carbon atoms represented by the above R Ｘ Examples of monovalent organic groups represented by can be given.

[0041] In the above formula (1), R １ and R ２ The cyclic structure (nitrogen atom-containing heterocyclic structure) formed when these elements are combined with each other and bonded together with the nitrogen atom may be monocyclic, polycyclic, or a combination thereof. The cyclic structure may include nitrogen atom-containing heterocyclic structures, and may also be a combination of alicyclic structures, aromatic structures, or heterocyclic structures. In the case of a combination, the cyclic structures may be linked in a chain-like structure, and two or more cyclic structures may form a fused ring structure, a bridged ring structure, or a spiro-ring structure. Divalent heteroatom-containing groups may be present between carbon atoms forming the skeleton of the cyclic or chain-like structure, and some or all of the hydrogen atoms on the carbon atoms of the cyclic or chain-like structure may be substituted with other substituents.

[0042] Examples of nitrogen atom-containing heterocyclic structures include nitrogen atom-containing aliphatic heterocyclic structures such as aziridine, azetidine, pyrrolidine, piperidine, and piperazine; nitrogen atom-containing aromatic heterocyclic structures such as pyrrole, imidazole, pyrazole, and triazine; aliphatic heterocyclic structures containing a nitrogen atom and other heteroatoms such as morpholine; and aromatic heterocyclic structures containing a nitrogen atom and other heteroatoms such as oxazole, isothiazole, and thiazine.

[0043] The above alicyclic structure is R Ｘ A structure corresponding to a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms can be suitably adopted.

[0044] The above aromatic ring structure is R Ｘ A structure corresponding to a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms can be suitably adopted.

[0045] Examples of the above heterocyclic structures include: oxygen atom-containing aliphatic heterocyclic structures such as oxiran, tetrahydrofuran, tetrahydropyran, dioxolane, and dioxane; sulfur atom-containing aliphatic heterocyclic structures such as thiethane, thioran, and thian; aliphatic heterocyclic structures containing multiple types of heteroatoms such as 1,2-oxathioran and 1,3-oxathioran; oxygen atom-containing aromatic heterocyclic structures such as furan and benzofuran; and sulfur atom-containing aromatic heterocyclic structures such as thiophene.

[0046] Heterocyclic structures include lactone structures, cyclic carbonate structures, sultone structures, cyclic acetal structures, or combinations thereof. Examples of such structures include those represented by the following formulas (H-1) to (H-11).

[0047] (In the above formula, g is an integer between 1 and 3.)

[0048] The above chain-like structure is R Ｘ In this material, monovalent chain hydrocarbon groups having 1 to 20 carbon atoms, or divalent chain hydrocarbon groups obtained by removing one hydrogen atom from the monovalent chain hydrocarbon group, can be suitably used.

[0049] As a divalent heteroatom-containing group, the above R Ｘ In monovalent organic groups having 1 to 20 carbon atoms, as shown, divalent heteroatom-containing groups can be suitably adopted.

[0050] Examples of substituents that substitute for some or all of the hydrogen atoms on the carbon atoms of the above-mentioned cyclic or chain structure include halogen atoms such as fluorine, chlorine, bromine, and iodine; hydroxyl groups; carboxyl groups; cyano groups; nitro groups; alkyl groups, alkoxy groups, alkoxycarbonyl groups, alkoxycarbonyloxy groups, acyl groups, acyloxy groups, or groups in which the hydrogen atoms of these groups are substituted with halogen atoms; and substituents (T) such as oxo groups (=O).

[0051] The above R ａ This is a substructure represented by the above formula (a-1).

[0052] In formula (1) above, the carbon atom at the α position of the sulfur atom is -CN, -F, -CF ２ H, and -SO ２ R ｔ２ Preferably, it has at least one group selected from the group consisting of -CN, -SO ２ R ｔ２ It is even more preferable to have this feature.

[0053] It is preferable that the compound represented by formula (1) above is the compound represented by formula (1-1) below. (In equation (1-1), W is a nitrogen-containing alicyclic heterocycle. R １１ R is a cyano group, nitro group, hydroxyl group, carboxyl group, or a monovalent organic group having 1 to 5 carbon atoms, or two or more R １１ These atoms are combined with each other to form a cyclic structure with 3 to 20 carbon atoms, along with the atoms to which they bond. １１ If multiple R １１ These are either identical or different. n1 is an integer between 0 and 5. ａ This is equivalent to equation (1).

[0054] Examples of nitrogen-containing alicyclic heterocycles represented by W above include aziridine, pyrrolidine, piperidine, piperazine, and morpholine, among which pyrrolidine and piperidine are preferred.

[0055] R １１ As a monovalent organic group having 1 to 5 carbon atoms represented by the above R Ｘ Among the monovalent organic groups represented by , those with the corresponding number of carbon atoms can be suitably adopted.

[0056] Two or more R's as described above １１ The cyclic structure formed when these groups are combined with each other and bonded together with the atoms may be monocyclic, polycyclic, or a combination thereof. The cyclic structure may also be alicyclic, aromatic, heterocyclic, or a combination thereof. In the case of a combination, the cyclic structures may be linked in a chain-like structure, or two or more cyclic structures may form a fused ring structure. These structures are preferably included as the smallest basic skeleton of the cyclic structure. The number of cyclic structures as the basic skeleton in the organic group may be one or two or more. The divalent heteroatom-containing groups may be present between carbon atoms or at the ends of carbon chains forming the skeleton of the cyclic or chain-like structure, and hydrogen atoms on carbon atoms of the cyclic or chain-like structure may be substituted with other substituents.

[0057] The above-described alicyclic structures, aromatic ring structures, heterocyclic structures, chain-like structures, divalent heteroatom-containing groups, and substituents can be suitably adopted.

[0058] Examples of compounds represented by the above chemical formula (1) include compounds represented by the following formula.

[0059]

[0060] (The compound represented by formula (2)) (In formula (2), R １ and R ２ Each of these is independently either a cyano group, a nitro group, a monovalent organic group having 1 to 20 carbon atoms, or R １ and R ２ These atoms are combined with each other and, together with the atoms they bond to, form a cyclic structure.ａ This is a substructure represented by the above formula (a-1).

[0061] R １ and R ２ As a monovalent organic group having 1 to 20 carbon atoms represented by the above R Ｘ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably used.

[0062] The above R １ and R ２ The cyclic structure formed when these elements are combined with the carbon atoms to which they are bonded may be monocyclic, polycyclic, or a combination thereof. Furthermore, the cyclic structure may be an alicyclic structure, an aromatic ring structure, a heterocyclic structure, or a combination thereof (however, R １ and R ２ The cyclic structure containing the carbon atoms to which the group is bonded is an alicyclic structure or an aliphatic heterocyclic structure. In the case of combinations, the cyclic structures may be linked in a chain structure, and two or more cyclic structures may form a fused ring structure. These structures are preferably included as the smallest basic skeleton of the cyclic structure. The number of cyclic structures as the basic skeleton in the organic group may be one or two or more. The above-mentioned divalent heteroatom-containing group may be present between carbon atoms or at the ends of carbon chains forming the skeleton of the cyclic or chain structure, and hydrogen atoms on carbon atoms of the cyclic or chain structure may be substituted with other substituents.

[0063] The above-described alicyclic structures, aromatic ring structures, heterocyclic structures, chain-like structures, divalent heteroatom-containing groups, and substituents can be suitably adopted.

[0064] The above R ａ This is a substructure represented by the above formula (a-1).

[0065] In formula (2) above, the carbon atom at the α position of the sulfur atom is -CN, -F, -CF ２ H, and -SO ２ R ｔ２ Preferably, it has at least one group selected from the group consisting of -CN, -SO ２ R ｔ２ It is more preferable to have it.

[0066] Examples of compounds represented by the above chemical formula (2) include compounds represented by the following formula.

[0067]

[0068] (The compound represented by formula (3)) (In formula (3), R ３ R is a monovalent organic group having 1 to 20 carbon atoms. ａ This is a substructure represented by the above formula (a-1).

[0069] R ３ As a monovalent organic group having 1 to 20 carbon atoms represented by the above R Ｘ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably used.

[0070] The above R ａ This is a substructure represented by the above formula (a-1).

[0071] In formula (3) above, the carbon atom at the α position of the sulfur atom is -CN, -F, -CF ２ H, and -SO ２ R ｔ２ Preferably, it has at least one group selected from the group consisting of -CN, -SO ２ R ｔ２ It is more preferable to have it.

[0072] Examples of compounds represented by the above chemical formula (3) include compounds represented by the following formula.

[0073]

[0074] This composition may contain one or more radiation-sensitive acid-generating agents (A).

[0075] The lower limit of the content of the above-mentioned radiation-sensitive acid generator (A) (total amount if multiple types are included) is preferably 0.1 parts by mass, more preferably 0.5 parts by mass, and still more preferably 1 part by mass, per 100 parts by mass of the polymer (B) described later. The upper limit of the above-mentioned content ratio is preferably 60 parts by mass, more preferably 50 parts by mass, and still more preferably 40 parts by mass. By setting the content of the radiation-sensitive acid generator (A) within the above range, it is possible to exhibit better sensitivity, exposure margin, depth of field, pattern rectangularity, pattern circularity, CDU, LWR, and defect suppression during pattern formation.

[0076] <Polymer (B)> The polymer (B) is not particularly limited, but for example, if the radiation-sensitive composition is a positive-type radiation-sensitive composition, it is preferably an aggregate of polymerization chains containing a structural unit (I) having an acid-dissociable group (hereinafter this polymer is also called "base polymer (B1)"). An "acid-dissociable group" is a group that substitutes a hydrogen atom, such as a carboxyl group, a phenolic hydroxyl group, an alcoholic hydroxyl group, or a sulfo group, and dissociates upon the action of an acid.

[0077] Furthermore, if the above-mentioned radiation-sensitive composition is a negative-type radiation-sensitive composition, it is preferable that it is an aggregate of polymerization chains containing structural unit (II) having a phenolic hydroxyl group (hereinafter, this polymer is also referred to as "base polymer (B2)"). In this radiation-sensitive composition, because polymer (B2) has structural unit (II), the crosslinking reaction of polymer (B2) proceeds sufficiently, and the pattern-forming properties are excellent. The following describes each polymer.

[0078] (Polymer (B1)) Polymer (B1) is an aggregate of polymer chains having structural unit (I) containing an acid-dissociable group. In addition to structural unit (I), base polymer (B1) may also contain structural units having a phenolic hydroxyl group (II-1), a structural unit having an aromatic ring (III), a structural unit having at least one selected from the group consisting of lactone structures, cyclic carbonate structures, and sultone structures (IV), a structural unit having an amide bond (V), a structural unit having a polar group (VI), a structural unit having an aliphatic hydrocarbon group (VII), and the like. Each structural unit will be described below.

[0079] [Structural Unit (I)] Structural unit (I) is a structural unit containing an acid-dissociable group. An "acid-dissociable group" is a hydrogen atom-substituting group such as a carboxyl group, phenolic hydroxyl group, alcoholic hydroxyl group, or sulfo group, which dissociates upon the action of an acid. The radiation-sensitive composition exhibits excellent pattern-forming properties because the polymer (B1) contains structural unit (I).

[0080] The structural unit (I) is not particularly limited as long as it has an acid-dissociable group, and examples include a structural unit having a tertiary alkyl ester moiety, a structural unit having a structure in which the hydrogen atom of a phenolic hydroxyl group is replaced by a tertiary alkyl group, and a structural unit having an acetal bond. However, from the viewpoint of improving the pattern-forming properties of the radiation-sensitive composition, the structural unit represented by the following formula (3) (hereinafter also referred to as "structural unit (I-1)") is preferred.

[0081]

[0082] In the above formula (3), R １７ R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. １８ R is a monovalent substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms. １９ and R ２０ Each of these independently represents either a monovalent substituted or unsubstituted linear hydrocarbon group having 1 to 10 carbon atoms, a monovalent substituted or unsubstituted alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a divalent alicyclic group having 3 to 20 carbon atoms formed by combining these groups with the carbon atoms to which they are bonded. １１ teeth, ＊ -COO-, ＊ -L １１ａ COO- or ＊ -COOL １１ａ Represents COO-. １１ａ * is a substituted or unsubstituted alkanediyl group or arenediyl group. １７ This is the bonding site with the carbon atom to which it is bonded.

[0083] The above R １７From the viewpoint of copolymerization of the monomer that gives the structural unit (I-1), hydrogen atoms and methyl groups are preferred, and methyl groups are more preferred.

[0084] L １１ａ Examples of alkanediyl groups represented by include methylene groups, ethanediyl groups, 1,3-propanediyl groups, and 2,2-propanediyl groups, which have 1 to 10 carbon atoms. １１ａ Methylene groups and ethanediyl groups are preferred as the components.

[0085] L １１ａ Examples of the arenediyl group represented by include divalent aromatic hydrocarbon groups having 6 to 20 carbon atoms, such as benzenediyl groups and naphthalenediyl groups. １１ａ A benzenediyl group is preferred as the group.

[0086] L １１ａ The substituent (T) shown above can be suitably adopted as the substituent that the alkanediyl group and arenediyl group represented by can have.

[0087] The above R １８ As a monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the above formula (a-1), R Ｘ Monovalent hydrocarbon groups having 1 to 20 carbon atoms can be suitably used in this material.

[0088] The above R １８ Preferably, the group is a linear or branched saturated hydrocarbon group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms.

[0089] The above R １９ and R ２０ The monovalent chain hydrocarbon group having 1 to 10 carbon atoms represented by the above R is Ｘ Among the monovalent chain hydrocarbon groups having 1 to 20 carbon atoms, those with the corresponding number of carbon atoms can be suitably adopted.

[0090] The above R １９ and R ２０ As a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by the above formula (a-1), R Ｘ A monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms can be suitably used in this material.

[0091] The above R １９ and R ２０ The divalent alicyclic group having 3 to 20 carbon atoms, which is formed when these are combined with the carbon atoms to which they are bonded, is R in formula (a-1) above. Ｘ A group obtained by removing one hydrogen atom from a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms can be suitably adopted.

[0092] The above R １９ and R ２０ Each of these is independently an alkyl group having 1 to 4 carbon atoms, or R １９ and R ２０ It is preferable that these are polycyclic or monocyclic cycloalkane structures formed by combining them with carbon atoms to which they are bonded.

[0093] The above R １８ ~R ２０ The substituents that can be present are L １１ａ The substituents that the alkanediyl group and arenediyl group represented by can have can be suitably adopted.

[0094] Examples of structural units (I-1) include those represented by the following formulas (3-1) to (3-16) (hereinafter also referred to as "structural units (I-1-1) to (I-1-16)").

[0095]

[0096]

[0097] In the above formulas (3-1) to (3-16), R １７ ~R ２０ This is equivalent to equation (3) above. R Ｌ１１ R is a halogen atom, hydroxyl group, carboxyl group, cyano group, nitro group, alkyl group, fluorinated alkyl group, alkoxycarbonyloxy group, acyl group, acyloxy group, or alkoxy group. i and j are each independently integers from 1 to 4. k and l are 0 or 1. a3 are each independently integers from 0 to 3. If a3 is 2 or more, multiple R Ｌ１１ They are either identical or different from each other. a4 is an integer between 1 and 3.

[0098] i and j are preferably 1 or 2. １８ Preferred groups include methyl, ethyl, isopropyl, t-butyl, cyclopentyl, ethenyl, adamantyl, phenyl, and iodophenyl groups. １９ and R ２０ Preferably, the group is a methyl group, an ethyl group, or an isopropyl group. Ｌ１１ By employing an iodine atom, an iodine group can be suitably introduced into the structural unit (I).

[0099] Furthermore, the polymer may contain structural units (I) represented by the following formulas (1f) to (2f).

[0100]

[0101] In the above equations (1f) to (2f), R αｆ Each of these is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. βｆ Each of these is independently a hydrogen atom or a chain alkyl group having 1 to 5 carbon atoms. h1 is an integer from 1 to 4.

[0102] The above R βｆ Preferably, the element is a hydrogen atom, a methyl group, or an ethyl group. H1 is preferably 1 or 2.

[0103] The base polymer (B1) may contain one or more structural units (I) in combination.

[0104] The lower limit of the content of structural unit (I) (total content if multiple types are included) is preferably 3 mol%, more preferably 5 mol%, and even more preferably 8 mol%, relative to the total structural units constituting the base polymer (B1). The upper limit of the above content is preferably 60 mol%, more preferably 50 mol%, and even more preferably 55 mol%. By setting the content of structural unit (I) within the above range, the pattern-forming properties of the radiation-sensitive composition can be further improved.

[0105] [Structural Unit (II-1)] Structural Unit (II-1) is a structural unit having a phenolic hydroxyl group. Structural Unit (II-1) contributes to improving etching resistance and improving the difference in developer solubility (dissolution contrast) between exposed areas and unexposed areas. The present invention can be suitably applied to pattern formation using exposure to radiation with a wavelength of 50 nm or less, such as electron beams or EUV.

[0106] The structural unit having a phenolic hydroxyl group is preferably represented by the following formula (4).

[0107] (In the above formula (4), R β is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. L ＣＡ is a single bond, -COO- ＊ or -O-. * represents a bonding bond on the aromatic ring side. R １０２ is a halogen atom, a cyano group, a nitro group, an alkyl group, an alkoxycarbonyl group, an acyl group or an acyloxy group. When a plurality of R １０２ are present, the plurality of R １０２ may be the same or different from each other. n ３ is an integer of 0 to 2, m ３ is an integer of 1 to 8, and m ４ is an integer of 0 to 8. Provided that 1≦m ３ +m ４ ≦2n ３ +5 is satisfied.)

[0108] As the above R β , a hydrogen atom or a methyl group is preferable from the viewpoint of copolymerizability of the monomer that provides structural unit (II-1).

[0109] As L ＣＡ , a single bond or -COO- ＊ is preferable.

[0110] As R １０２ , the halogen atom is preferably an iodine atom or a fluorine atom, and more preferably a fluorine atom.

[0111] As the above n ３ , 0 or 1 is more preferable, and 0 is even more preferable.

[0112] In the above m ３ , an integer of 1 to 3 is preferable, and 1 or 2 is more preferable.

[0113] In the above m ４ , an integer of 0 to 3 is preferable, and an integer of 0 to 2 is more preferable.

[0114] The base polymer (B1) may contain one type or a combination of two or more types of the structural unit (II-1).

[0115] When the base polymer (B1) contains the structural unit (II-1), the lower limit of the content ratio of the structural unit (II-1) (the total content ratio when two or more types are contained) is preferably 10 mol% and more preferably 20 mol%, based on all structural units constituting the base polymer (B1). Further, the upper limit of the content ratio is preferably 100 mol%, and more preferably 80 mol%.

[0116] [Structural Unit (III)] The structural unit (III) is a structural unit having an aromatic ring (excluding those falling under the aforementioned structural unit (II-1)). It is preferable from the viewpoint of etching resistance that the base polymer (B1) further has the structural unit (III).

[0117] As the aforementioned structural unit (III), a structural unit represented by the following formula (5) is preferable.

[0118] (In the above formula (5), R Ａ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. L ＣＡ is a single bond, -COO- ＊ or -O-. * is a bond on the aromatic ring side. X １ is a halogen atom, a cyano group, a nitro group, an alkyl group, an alkoxy group, a carboxy group, a fluorinated alkyl group, an alkoxycarbonyl group, an acyl group or an acyloxy group. When a plurality of X １ exist, the plurality of X １ may be the same or different from each other. q3 is an integer of 0 to 2, and q4 is an integer of 0 to 8.)

[0119] The above R A is preferably a hydrogen atom or a methyl group.

[0120] The above L ＣＡ For example, a single bond or -COO- ＊ A single bond is preferred, and a single bond is even more preferred.

[0121] X １ Preferably, the group is an alkyl group or a carboxyl group.

[0122] For q3, 0 or 1 is preferred, and 0 is more preferred.

[0123] For q4, an integer between 0 and 3 is preferred, and 0 or 1 is more preferred.

[0124] The above structural unit (III) is preferably a structural unit represented by the following formula. In the following formula, R Ａ This is the same as equation (5) above.

[0125]

[0126] The base polymer (B1) may contain one or more structural units (III) in combination.

[0127] When the base polymer (B1) contains the structural unit (III), the lower limit of the content of the structural unit (III) (total if there are multiple types of structural unit (III)) is preferably 1 mol%, more preferably 3 mol%, and even more preferably 5 mol%, relative to the total structural units constituting the polymer (B1-1). The upper limit of the content is preferably 60 mol%, more preferably 50 mol%, and even more preferably 40 mol%. By setting the content of structural unit (III) within the above range, the radiation-sensitive composition can be made to further improve etching resistance and sensitivity.

[0128] [Structural Unit (IV)] Structural unit (IV) is a structural unit comprising at least one selected from the group consisting of lactone structures, cyclic carbonate structures, and sultone structures. By further comprising structural unit (IV) in the base polymer (B1), the solubility in the developer can be adjusted, and as a result, the radiation-sensitive composition can improve lithography performance such as resolution. In addition, the adhesion between the resist pattern formed from the base polymer (B1) and the substrate can be improved.

[0129] Examples of structural units (IV) include those represented by the following formulas (T-1) to (T-11).

[0130]

[0131] In the above formula, R Ｌ１ R is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Ｌ２ ~R Ｌ５ These are, independently, a hydrogen atom, a C1-C4 alkyl group, a cyano group, a trifluoromethyl group, a methoxy group, a methoxycarbonyl group, a hydroxyl group, a hydroxymethyl group, and a dimethylamino group. Ｌ４ and R Ｌ５ These may be divalent alicyclic groups having 3 to 8 carbon atoms, which can be combined with each other and bonded together with the carbon atoms. ２ is a single bond or a divalent linking group. X is an oxygen atom or a methylene group. k is an integer from 0 to 3. m is an integer from 1 to 3.

[0132] The above R Ｌ４ and R Ｌ５ When these are combined with each other, the divalent alicyclic group having 3 to 8 carbon atoms, formed together with the carbon atoms to which they are bonded, is R in formula (3) above. １９ and R ２０ Examples include divalent alicyclic groups with 3 to 20 carbon atoms, where these groups are combined with each other and formed together with the carbon atoms to which they are bonded, specifically groups with 3 to 8 carbon atoms. One or more hydrogen atoms on these alicyclic groups may be substituted with hydroxyl groups.

[0133] The above L ２Examples of divalent linking groups represented by include divalent linear or branched hydrocarbon groups having 1 to 10 carbon atoms, divalent alicyclic hydrocarbon groups having 4 to 12 carbon atoms, or groups composed of one or more of these hydrocarbon groups and at least one of the groups -CO-, -O-, -NH-, and -S-.

[0134] Among these, structural units (IV) are preferably those containing a lactone structure, more preferably those containing a γ-butyrolactone structure or a norbornane lactone structure, and even more preferably those derived from γ-butyrolactone-yl-(meth)acrylate or norbornane lactone-yl(meth)acrylate.

[0135] The base polymer (B1) may contain one or more structural units (IV) in combination.

[0136] When the base polymer (B1) has structural units (IV), the lower limit of the content of structural units (IV) (total content if multiple types are included) is preferably 3 mol%, more preferably 5 mol%, and even more preferably 8 mol%, relative to the total structural units constituting the base polymer (B1). The upper limit of the content is preferably 60 mol%, more preferably 50 mol%, and even more preferably 40 mol%. By setting the content of structural units (IV) within the above range, the radiation-sensitive composition can further improve lithography performance such as resolution and the adhesion of the formed resist pattern to the substrate.

[0137] (Structural Unit (V)) Structural unit (V) is a structural unit that contains an amide bond.

[0138] The above structural unit (V) is preferably a structural unit derived from a compound represented by the following formula (8). (In formula (8), R １００ L is a hydrogen atom, a fluorine atom, or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. １０１ R is a single bond or a divalent linking group. １０１ and R １０２ These are, independently, monovalent organic groups having 1 to 20 carbon atoms.

[0139] R １００ As the substituted or unsubstituted alkyl group having 1 to 6 carbon atoms represented by Ｘ , among the alkyl groups for R in the above formula (a-1), those having 1 to 6 carbon atoms can be suitably employed.

[0140] L １０１ As the divalent linking group represented by , a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms and a divalent chain hydrocarbon group having 1 to 10 carbon atoms are preferred, and benzenediyl groups, ethanediyl groups, propanediyl groups and the like are more preferred. Some or all of the hydrogen atoms in these groups may be substituted with the above monovalent heteroatom-containing group.

[0141] R １０１ and R １０２ , as the monovalent organic group having 1 to 20 carbon atoms represented by R in the above formula (a-1), Ｘ a monovalent organic group having 1 to 20 carbon atoms represented by can be suitably employed. Among these, as R １０１ and R １０２ , an alkyl group having 1 to 5 carbon atoms is preferred.

[0142] The base polymer (B1) may contain one type of structural unit (V), or a combination of two or more types thereof.

[0143] When the above base polymer (B1) contains the above structural unit (V), the lower limit of the content ratio of the above structural unit (V) (the total content ratio when multiple types are contained) relative to all structural units constituting the base polymer (B1) is preferably 1 mol%, more preferably 5 mol%, and still more preferably 8 mol%. Further, the upper limit of the above content ratio is preferably 50 mol%, more preferably 40 mol%, and still more preferably 30 mol%.

[0144] [Structural Unit (VI)] Structural unit (VI) is a structural unit containing a polar group (excluding those corresponding to structural units (I) to (V)). The presence of structural unit (VI) allows for adjustment of solubility in the developer, thereby improving the lithographic performance, such as resolution, of the radiation-sensitive composition. Examples of the polar group include a hydroxyl group, a carboxyl group, a cyano group, a nitro group, and a sulfonamide group. Among these, hydroxyl groups and carboxyl groups are preferred, with hydroxyl groups being more preferred.

[0145] Examples of structural units (VI) include structural units represented by the following formula.

[0146]

[0147]

[0148] In the above formula, R Ｋ This is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0149] The base polymer (B1) may contain one or more structural units (VI) in combination.

[0150] When the base polymer (B1) has structural units (VI) having the polar group, the lower limit of the content of structural units (VI) (total content if multiple types are included) is preferably 1 mol%, more preferably 2 mol%, and even more preferably 3 mol%, relative to the total structural units constituting the base polymer (B1). The upper limit of the above content is preferably 40 mol%, more preferably 30 mol%, and even more preferably 25 mol%. By setting the content of structural units (VI) within the above range, the lithographic performance, such as resolution, of the radiation-sensitive composition can be further improved.

[0151] [Structural Unit (VII)] In addition to the structural units listed above, the base polymer (B1) may include structural units having an aliphatic hydrocarbon group represented by the following formula (6) (hereinafter also referred to as "structural unit (VII)"). (In the above formula (6), R １αR is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. ２α (This refers to a monovalent hydrocarbon group having 1 to 40 carbon atoms.)

[0152] In the above formula (6), R ２α As a monovalent hydrocarbon group having 1 to 40 carbon atoms represented by the above formula (a-1), R Ｘ In this material, monovalent hydrocarbon groups with 1 to 20 carbon atoms can be preferably adopted, with the number of carbon atoms extended to 1 to 40.

[0153] The base polymer (B1) may contain one or more structural units (VII) in combination.

[0154] When the base polymer (B1) contains the above structural unit (VII), the lower limit of the content of the above structural unit (VII) (total content if multiple types are included) is preferably 1 mol%, more preferably 3 mol%, and even more preferably 5 mol%, relative to the total structural units constituting the base polymer (B1). The upper limit of the above content is preferably 50 mol%, more preferably 40 mol%, and even more preferably 30 mol%.

[0155] (Method for synthesizing base polymer (B1)) Base polymer (B1) can be synthesized, for example, by polymerizing monomers that give each structural unit in a suitable solvent using a radical polymerization initiator or the like.

[0156] Examples of the radical polymerization initiators mentioned above include azo-based radical initiators such as azobisisobutyronitrile (AIBN), 2,2'-azobis(isobutyrate)dimethyl (MAIB), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and dimethyl 2,2'-azobisisobutyrate; and peroxide-based radical initiators such as benzoyl peroxide, t-butyl hydroperoxide, and cumene hydroperoxide. Among these, AIBN and dimethyl 2,2'-azobisisobutyrate are preferred. These radical initiators can be used individually or in combination of two or more.

[0157] Examples of solvents used in the above polymerization include: alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane; cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, and norbornane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and cumene; halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, and chlorobenzene; saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, isobutyl acetate, and methyl propionate; polyhydric alcohol partial ether acetate solvents such as diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol monomethyl ether acetate; and ketones such as acetone, methyl ethyl ketone, 2-butanone, 4-methyl-2-pentanone, 2-heptanone, and cyclohexanone. Examples include linear ethers such as dimethoxyethanes and diethoxyethanes; cyclic ethers such as tetrahydrofurans and 1,4-dioxanes; polyhydric alcohol partial ethers such as 1-methoxy-2-propanol (propylene glycol monomethyl ether); alcohols such as methanol, ethanol, 1-propanol, 2-propanol, and 4-methyl-2-pentanol; and lactones such as γ-butyrolactone. The solvents used in these polymerizations may be used alone or in combination of two or more.

[0158] The reaction temperature in the polymerization described above is usually 40°C to 150°C, with 50°C to 120°C being preferred. The reaction time is usually 1 hour to 48 hours, with 1 hour to 24 hours being preferred.

[0159] The molecular weight of the base polymer (B1) is not particularly limited, but the lower limit of the polystyrene-equivalent weight-average molecular weight (Mw) determined by gel permeation chromatography (GPC) is preferably 2,000, more preferably 3,000, and even more preferably 4,000. The upper limit of Mw is preferably 30,000, more preferably 25,000, and even more preferably 20,000. By keeping the Mw of the base polymer (B1) within the above range, good heat resistance and developability can be obtained in the resulting resist film.

[0160] The ratio of Mw to the polystyrene-equivalent number-average molecular weight (Mn) (Mw / Mn) of the base polymer (B1) determined by GPC is usually between 1 and 5, preferably between 1 and 3, and more preferably between 1 and 2.

[0161] In this specification, the Mw and Mn values ​​of polymers are measured using gel permeation chromatography (GPC) under the following conditions.

[0162] GPC columns: 2 x G2000HXL, 1 x G3000HXL, 1 x G4000HXL (all manufactured by Tosoh Corporation) Column temperature: 40°C Elution solvent: Tetrahydrofuran Flow rate: 1.0 mL / min Sample concentration: 1.0% by mass Sample injection volume: 100 μL Detector: Differential refractometer Standard material: Monodisperse polystyrene

[0163] The content of the base polymer (B1) is preferably 60% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 70% by mass or more, based on the total solid content of the radiation-sensitive composition.

[0164] (Polymer (B2)) Examples of polymers (B2) containing a structural unit (II) having a phenolic hydroxyl group include polymers (B2-1) containing the structural unit (II-1) represented by formula (4) above, or novolac polymers (B2-2) containing the structural unit (II-2) represented by formula (10) described later.

[0165] (Polymer (B2-1)) [Structural Unit (II-1)] The structural unit (II-1) in the base polymer (B2-1) can preferably be the structural unit (II-1) in the polymer (B1) described above.

[0166] The lower limit of the content of structural unit (II-1) (or the total content if multiple types are included) is preferably 10 mol%, and more preferably 20 mol%, relative to the total structural units constituting the base polymer (B2-1). The upper limit of the above content is preferably 90 mol%, and more preferably 85 mol%.

[0167] The polymer (B2-1) described above may contain structural units (III) to (VII) as exemplified in the base polymer (B1), in addition to structural unit (II-1), and it is particularly preferable that it contains structural unit (III) and structural unit (VI). The proportions of these can be the same range as in the content of each structural unit in polymer (B1), but with "base polymer (B1)" replaced by "base polymer (B2-1)".

[0168] The synthesis method for the base polymer (B2-1) can be the same as the synthesis method for the base polymer (B1) described above.

[0169] The molecular weight of the base polymer (B2) and the ratio of Mw to the polystyrene-equivalent number-average molecular weight (Mn) (Mw / Mn) determined by GPC can be within the same range as that of the base polymer (B1).

[0170] (Polymer (B2-2)) Polymer (B2-2) contains structural unit (II-2) having a phenolic hydroxyl group. The base polymer (B2-2) may also contain structural units other than structural unit (II-2). Each structural unit is described below.

[0171] The structural unit (II-2) is preferably represented by the following formula (10).

[0172] (In formula (10), R ２０１ R is a monovalent organic group having 1 to 20 carbon atoms. ２０１ If multiple R ２０１(These two values ​​are either identical or different. a is an integer between 0 and 3.)

[0173] R ２０１ As a monovalent organic group having 1 to 20 carbon atoms represented by the above formula (a-1), R Ｘ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably used.

[0174] Polymer (B2-2) is a novolac polymer obtained by condensing a phenol compound and an aldehyde in the presence of a catalyst.

[0175] Examples of the phenol compounds mentioned above include phenol; o-, m- or p-cresol; 2,3-, 2,5-, 3,4- or 3,5-xylenol; 2,3,4- or 2,3,5-trimethylphenol; 2-,3- or 4-tert-butylphenol; 2-tert-butyl-4- or 5-methylphenol; 2-,4- or 5-methylresorcinol; 2-,3- or 4-methoxyphenol; 2,3-, 2,5- or 3,5-dimethoxyphenol; 2-methoxyresorcinol; 4-tert-butylcatechol; 2-,3- or 4-ethylphenol; 2,5- or 3,5-diethylphenol; 2,3,5-triethylphenol; 2-naphthol; 1,3-, 1,5- or 1,7-dihydroxynaphthalene; and polyhydroxytriphenylmethane compounds obtained by the condensation of xylenol with hydroxybenzaldehyde. These phenol compounds can be used individually or in combination of two or more. Among these, o-, m-, or p-cresol; 2,3-, 2,5-, 3,4-, or 3,5-xylenol; and 2,3,4-, or 2,3,5-trimethylphenol are preferred as phenol compounds.

[0176] Examples of aldehydes include aliphatic aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, acrolein, or crotonaldehyde; alicyclic aldehydes such as cyclohexanealdehyde, cyclopentanaldehyde, or furylacrolein; aromatic aldehydes such as furfural, benzaldehyde, o-, m-, or p-methylbenzaldehyde, p-ethylbenzaldehyde, 2,4-, 2,5-, 3,4-, or 3,5-dimethylbenzaldehyde, or o-, m-, or p-hydroxybenzaldehyde; and aromatic aliphatic aldehydes such as phenylacetaldehyde or cinnamaldehyde. These aldehydes can be used individually or in combination of two or more. Among these, formaldehyde is preferred because it is readily available industrially.

[0177] The condensation reaction between the above phenol compound and aldehyde can be carried out according to conventional methods.

[0178] Examples of the polymer (B2-2) mentioned above include polymers containing structural units represented by the following formulas (10-1) to (10-6). In the following formulas, the arrangement of each structural unit may be block-like or random.

[0179] The lower limit of the content of the above structural unit (II-2) (total content if multiple types are included) is preferably 20 mol%, more preferably 30 mol%, and even more preferably 40 mol%, relative to the total structural units constituting the polymer (B2-2). The upper limit of the above content is preferably 100 mol%. By setting the content of structural unit (II-2) within the above range, the radiation-sensitive composition can be made to further improve its sensitivity.

[0180] The weight-average molecular weight (Mw) and Mw / Mn of polymer (B2-2) can be given within the same range as for polymer (B1) described above.

[0181] <Other Polymers> The radiation-sensitive composition of this embodiment may also contain, as other polymers, a polymer (F) (hereinafter also referred to as "high-fluorine content polymer") having a higher mass content of fluorine atoms than the base polymer described above. When the radiation-sensitive composition contains a high-fluorine content polymer, it can be made to be unevenly distributed on the surface of the resist film relative to the base polymer (B), and as a result, it is possible to improve the water repellency of the surface of the resist film during immersion exposure, or to control the surface modification of the resist film and the distribution of the composition within the film during exposure.

[0182] High-fluorine-content polymers may, for example, have structural units represented by the following formula (5) (hereinafter also referred to as "structural unit (X)").

[0183]

[0184] In the above formula (5), R １３ This is a hydrogen atom, a methyl group, or a trifluoromethyl group. Ｌ It consists of a single bond, an alkanediyl group with 1 to 5 carbon atoms, an oxygen atom, a sulfur atom, -COO-, and -SO ２ ONH-, -CONH-, -OCONH-, or a combination thereof. １４ This is a monovalent fluorinated chain hydrocarbon group having 1 to 20 carbon atoms or a monovalent fluorinated alicyclic hydrocarbon group having 3 to 20 carbon atoms.

[0185] The above R １３ From the viewpoint of copolymerization of monomers that provide structural unit (X), hydrogen atoms and methyl groups are preferred, and methyl groups are more preferred.

[0186] The above G Ｌ From the viewpoint of copolymerization of monomers that provide structural units (X), single bonds and -COO- are preferred, and -COO- is more preferred.

[0187] The above R １４ Examples of monovalent fluorinated linear hydrocarbon groups having 1 to 20 carbon atoms, represented by , include those in which some or all of the hydrogen atoms in a linear or branched alkyl group having 1 to 20 carbon atoms are substituted with fluorine atoms.

[0188] The above R １４Examples of monovalent fluorinated alicyclic hydrocarbon groups having 3 to 20 carbon atoms, represented by , include those in which some or all of the hydrogen atoms in a monocyclic or polycyclic hydrocarbon group having 3 to 20 carbon atoms are substituted with fluorine atoms.

[0189] The above R １４ Preferably, the group is a fluorinated chain hydrocarbon group, more preferably a fluorinated alkyl group, and even more preferably a 2,2,2-trifluoroethyl group, a 2,2,3,3,3-pentafluoropropyl group, a 1,1,1,3,3,3-hexafluoropropyl-2-yl group, and a 5,5,5-trifluoro-1,1-diethylpentyl group.

[0190] When a high-fluorine-content polymer has structural units (X), the lower limit of the content of structural units (X) is preferably 50 mol%, more preferably 55 mol%, and even more preferably 60 mol%, relative to the total structural units constituting the high-fluorine-content polymer. The upper limit of the above content is preferably 95 mol%, more preferably 90 mol%, and even more preferably 85 mol%. By setting the content of structural units (X) within the above range, the mass content of fluorine atoms in the high-fluorine-content polymer can be more appropriately adjusted, further promoting the uneven distribution on the surface of the resist film, and as a result, the water repellency of the resist film during immersion exposure can be further improved.

[0191] High-fluorine polymers may have fluorine atom-containing structural units (hereinafter also referred to as structural unit (XI)) represented by the following formula (f-2), either together with or in place of structural unit (X). The presence of structural unit (XI) in high-fluorine polymers improves solubility in alkaline developers and suppresses the occurrence of development defects.

[0192]

[0193] Structural units (XI) can be broadly classified into two types: (x) those having an alkali-soluble group, and (y) those having a group that dissociates upon the action of alkali, increasing its solubility in an alkaline developer (hereinafter also simply referred to as an "alkali-dissociable group"). In both (x) and (y), in the above formula (f-2), R ＣR is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Ｄ R is a single bond, a (s+1) valent hydrocarbon group with 1 to 20 carbon atoms, and this hydrocarbon group Ｅ At the end of the side are an oxygen atom, a sulfur atom, and -NR ｄｄ -A structure to which a carbonyl group, -COO-, -OCO-, or -CONH- is bonded, or a structure in which some of the hydrogen atoms of this hydrocarbon group are substituted by an organic group having a heteroatom. ｄｄ is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. s is an integer from 1 to 3.

[0194] If structural unit (XI) has (x) an alkali-soluble group, R Ｆ A is a hydrogen atom, １ is an oxygen atom, -COO-* or -SO ２ It is O-*. * is R Ｆ This indicates the binding site. １ This is a single bond, a hydrocarbon group having 1 to 20 carbon atoms, or a divalent fluorinated hydrocarbon group. １ If is an oxygen atom, W １ is A １ It is a fluorinated hydrocarbon group having a fluorine atom or a fluoroalkyl group at the carbon atom to which it is bonded. Ｅ is a single bond or a divalent organic group having 1 to 20 carbon atoms. When s is 2 or 3, multiple R Ｅ , W １ A １ and R Ｆ These may be the same or different. Having an alkali-soluble group (x) in structural unit (XI) increases its affinity for alkaline developer and suppresses development defects. A structural unit (XI) having an alkali-soluble group is A １ is an oxygen atom and W １ It is particularly preferable that the group is a 1,1,1,3,3,3-hexafluoro-2,2-methanediyl group.

[0195] If structural unit (XI) has an alkali-dissociable group (y), R Ｆ A is a monovalent organic group having 1 to 30 carbon atoms. １ is an oxygen atom, -NR ａａ-, -COO-*, -OCO-*, or -SO ２ It is O-*. ａａ * is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. Ｆ This indicates the binding site. １ R is a single bond or a divalent fluorinated hydrocarbon group having 1 to 20 carbon atoms. Ｅ A is a single bond or a divalent organic group having 1 to 20 carbon atoms. １ -COO-*, -OCO-*, or -SO ２ If it is O-*, then W １ or R Ｆ is A １ It has a fluorine atom on the carbon atom bonded to it or on an adjacent carbon atom. １ If is an oxygen atom, W １ , R Ｅ It is a single bond, R Ｄ R is a hydrocarbon group having 1 to 20 carbon atoms. Ｅ It is a structure in which a carbonyl group is bonded to the terminal end, R Ｆ is an organic group having a fluorine atom. When s is 2 or 3, multiple R Ｅ , W １ A １ and R Ｆ These may be the same or different. The presence of a (y) alkali-dissociable group in structural unit (XI) causes the resist film surface to change from hydrophobic to hydrophilic during the alkali development process. As a result, the affinity for the developer is significantly increased, and development defects can be suppressed more efficiently. Examples of structural units (XI) having a (y) alkali-dissociable group include A １ is -COO-* or -OCO-*, R Ｆ Or W １ Alternatively, it is particularly preferable that both of these contain fluorine atoms.

[0196] R Ｃ From the viewpoint of copolymerizability of monomers that provide structural unit (XI), hydrogen atoms and methyl groups are preferred, and methyl groups are more preferred.

[0197] When a high-fluorine-content polymer has structural units (XI), the lower limit of the content of structural units (XI) is preferably 20 mol%, more preferably 30 mol%, and even more preferably 35 mol%, relative to the total structural units constituting the high-fluorine-content polymer. The upper limit of the above content is preferably 95 mol%, more preferably 90 mol%, and even more preferably 85 mol%. By setting the content of structural units (XI) within the above range, it is possible to improve the water repellency of the resist film during immersion exposure and improve solubility in alkaline developers, thereby suppressing the occurrence of development defects.

[0198] [Other structural units] High-fluorine polymers may, if necessary, include structural units other than those listed above, such as structural unit (I) and structural unit (VI) in the base polymer.

[0199] When a high-fluorine-content polymer contains structural unit (I), the lower limit of the content of structural unit (I) is preferably 1 mol%, and more preferably 5 mol%, relative to the total structural units constituting the high-fluorine-content polymer. The upper limit of the above content is preferably 70 mol%, and more preferably 60 mol%.

[0200] When a high-fluorine-content polymer contains structural units (VI), the lower limit of the content of structural units (VI) is preferably 1 mol%, and more preferably 3 mol%, relative to the total structural units constituting the high-fluorine-content polymer. The upper limit of the above content is preferably 50 mol%, and more preferably 40 mol%.

[0201] The lower limit of Mw for the high-fluorine-content polymer is preferably 4,000, more preferably 5,000, and even more preferably 6,000. The upper limit of Mw is preferably 20,000, and more preferably 15,000.

[0202] The lower limit of Mw / Mn for high-fluorine-content polymers is usually 1, and 1.1 is more preferred. The upper limit of Mw / Mn is usually 5, 3 is preferred, and 2 is more preferred.

[0203] If the radiation-sensitive composition contains a high-fluorine-content polymer, the lower limit of the high-fluorine-content polymer content is preferably 0.5 parts by mass, more preferably 1 part by mass, and even more preferably 1.5 parts by mass, per 100 parts by mass of the base polymer (B). The upper limit of the above content is preferably 15 parts by mass, more preferably 10 parts by mass, and even more preferably 8 parts by mass.

[0204] By setting the content of the high-fluorine polymer within the above range, the high-fluorine polymer can be more effectively distributed to the surface layer of the resist film. As a result, it is possible to improve the water repellency of the surface of the resist film during immersion exposure, and to control the surface modification of the resist film and the distribution of its internal composition during exposure. The radiation-sensitive composition may contain one or more high-fluorine polymers.

[0205] (Method for synthesizing high-fluorine content polymers) High-fluorine content polymers can be synthesized by the same method as the synthesis method for the base polymer (B1) described above.

[0206] <Crosslinking agent (Q)> The above radiation-sensitive composition may contain a crosslinking agent (Q). The type of crosslinking agent (Q) is not particularly limited, and examples include crosslinking agents having two or more crosslinking groups in one molecule. The number of crosslinking groups is two or more per molecule, preferably 2 to 10, and more preferably 2 to 6.

[0207] The above crosslinkable group is not particularly limited, but it is preferable to have at least one selected from the group consisting of a methylol group, an alkoxymethyl group, a glycidyl group, a (meth)acryloyl group, and a vinyl group, more preferably a methylol group or an alkoxymethyl group, and even more preferably an alkoxymethyl group.

[0208] The above-mentioned radiation-sensitive composition can be made into a negative-type pattern-forming composition by containing a crosslinking agent (Q). Specifically, in the exposed area, the acid generated from the radiation-sensitive acid generator (A) or the radiation-sensitive acid generator (P) described later promotes the crosslinking reaction of the polymer (B2) by the crosslinking agent (Q), causing it to harden and become substantially insoluble in alkaline developer. On the other hand, by removing the unexposed area with alkaline developer, a negative-type pattern can be formed.

[0209] The crosslinking agent (Q) is not particularly limited, but examples include amino-based crosslinking agents having one or more nitrogen atoms, and phenolic hydroxyl group-containing crosslinking agents.

[0210] The above-mentioned amino-based crosslinking agents are not particularly limited, as long as they have one or more nitrogen atoms, but examples include glycoluryl-type crosslinking agents having a glycoluryl skeleton, melamine-type crosslinking agents having a melamine skeleton, and urea-type crosslinking agents having a cyclic alkylene urea skeleton.

[0211] Among these, amino-based crosslinking agents are preferred as the crosslinking agent (Q), and glycoluryl-type crosslinking agents and melamine-type crosslinking agents are more preferred.

[0212] Examples of the glycoluryl-type crosslinking agent mentioned above include the compound (Q1) represented by the following formula (Q1). (In formula (Q1), R ３１ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. However, at least two R ３１ is *-R ３３ -OR ３４ (R ３３ R is a divalent hydrocarbon group having 1 to 10 carbon atoms. ３４ R is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. * indicates a bond with a nitrogen atom. ３２ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms.

[0213] The above R ３１ In this, the monovalent organic group having 1 to 20 carbon atoms is R in formula (a-1) above. ＸA monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably used.

[0214] The above R ３３ In this, the divalent hydrocarbon group having 1 to 10 carbon atoms is R in the above formula (a-1). Ｘ In this context, a monovalent hydrocarbon group having 1 to 20 carbon atoms can be suitably adopted, which is obtained by removing one hydrogen atom from the corresponding carbon number group.

[0215] The above R ３４ In this, the monovalent hydrocarbon group having 1 to 10 carbon atoms is R in the above formula (a-1). Ｘ Among the monovalent hydrocarbon groups having 1 to 20 carbon atoms, those with the corresponding number of carbon atoms can be suitably adopted.

[0216] The above R ３２ In this, the monovalent organic group having 1 to 10 carbon atoms is R in formula (a-1) above. Ｘ Among the monovalent organic groups having 1 to 20 carbon atoms represented by [formula], those with the corresponding number of carbon atoms can be suitably adopted.

[0217] As the glycoluryl type crosslinking agent, the compound represented by the following formula (Q1-1) (Q1-1) is preferred. (In formula (Q1-1), R ３２ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms. ３３ Each of these is independently a divalent hydrocarbon group having 1 to 10 carbon atoms. ３４ These are, independently, monovalent hydrocarbon groups having 1 to 10 carbon atoms.

[0218] R ３２ A monovalent organic group having 1 to 10 carbon atoms, R ３３ A divalent hydrocarbon group having 1 to 10 carbon atoms, R ３４ As the monovalent hydrocarbon group having 1 to 10 carbon atoms in the above formula (Q1), the monovalent organic group having 1 to 10 carbon atoms, the divalent hydrocarbon group having 1 to 10 carbon atoms, and the monovalent hydrocarbon group having 1 to 10 carbon atoms can be suitably adopted.

[0219] Among these, the above R ３２As such, a hydrogen atom or an alkyl group having 1 to 3 carbon atoms is preferred. ３３ As for the group, an alkylene group having 1 to 5 carbon atoms is preferred, and a methylene group or an ethylene group is more preferred. ３４ Preferably, the alkyl group has 1 to 5 carbon atoms, and more preferably, a methyl group or a butyl group.

[0220] Examples of glycoluryl-type crosslinking agents include those with the following formulas.

[0221] (In the formula, Et is an ethyl group, ｎ Bu is an n-butyl group, ｉ Pr represents an isopropyl group.

[0222] Examples of the melamine-type crosslinking agent mentioned above include the compound (Q2) represented by the following formula (Q2). (In formula (Q2), R ４ Each of these is independently a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. However, at least two R ４ is *-R ４１ -OR ４２ (R ４１ R is a divalent hydrocarbon group having 1 to 10 carbon atoms. ４２ This represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. * indicates a bond with a nitrogen atom.

[0223] The above R ４ In this, the monovalent organic group having 1 to 20 carbon atoms is R in formula (a-1) above. Ｘ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably used.

[0224] The above R ４１ In this, the divalent hydrocarbon group having 1 to 10 carbon atoms is R in the above formula (a-1). Ｘ In this context, a monovalent hydrocarbon group having 1 to 20 carbon atoms can be suitably adopted, which is obtained by removing one hydrogen atom from the corresponding carbon number group.

[0225] The above R ４２ In this, the monovalent hydrocarbon group having 1 to 10 carbon atoms is R in the above formula (a-1). ＸAmong the monovalent hydrocarbon groups having 1 to 20 carbon atoms, those with the corresponding number of carbon atoms can be suitably adopted.

[0226] As the melamine-type crosslinking agent, a compound represented by the following formula (Q2-1) (Q2-1) is preferred. (In formula (Q2-1), R ４１ Each of these is independently a divalent hydrocarbon group having 1 to 10 carbon atoms. ４２ These are, independently, monovalent hydrocarbon groups having 1 to 10 carbon atoms.

[0227] R ４１ A divalent hydrocarbon group having 1 to 10 carbon atoms, R ４２ As the monovalent hydrocarbon group having 1 to 10 carbon atoms in the above formula (Q2), the divalent hydrocarbon group having 1 to 10 carbon atoms and the monovalent hydrocarbon group having 1 to 10 carbon atoms listed above can be suitably adopted.

[0228] Among these, the above R ４１ As for the group, an alkylene group having 1 to 5 carbon atoms is preferred, and a methylene group or an ethylene group is more preferred. ４２ Preferably, the alkyl group has 1 to 5 carbon atoms, and more preferably, a methyl group.

[0229] Examples of melamine-type crosslinking agents include those with the following formulas.

[0230] (In the formula, Me is a methyl group, Et is an ethyl group, ｎ Bu is an n-butyl group, ｉ Pr represents an isopropyl group.

[0231] Furthermore, the following crosslinking agents can be cited as urea-type crosslinking agents having the above-mentioned cyclic alkylene urea skeleton.

[0232]

[0233] Furthermore, the following crosslinking agents can be listed as phenolic hydroxyl group-containing crosslinking agents.

[0234]

[0235] In the present invention, the above-mentioned crosslinking agent (Q) can be used alone or in combination of two or more types.

[0236] The lower limit of the content of the above-mentioned crosslinking agent (Q) (total if multiple types of crosslinking agents (Q) are included) is preferably 0.5 parts by mass, more preferably 1 part by mass, and even more preferably 3 parts by mass, per 100 parts by mass of polymer (B2). The upper limit of the above-mentioned content is preferably 30 parts by mass, and more preferably 20 parts by mass. The content of the above-mentioned crosslinking agent (Q) is appropriately selected depending on the type of polymer used, exposure conditions, and the required sensitivity. This enables excellent pattern circularity when forming a resist pattern.

[0237] <Acid Diffusion Control Agent (D)> The above radiation-sensitive composition may optionally contain an acid diffusion control agent (D). The acid diffusion control agent (D) controls the diffusion phenomenon of acids generated from the above radiation-sensitive acid generator (A) or the radiation-sensitive acid generator (P) described later in the resist film upon exposure, and has the effect of suppressing undesirable chemical reactions in the non-exposed areas. In addition, the storage stability of the obtained radiation-sensitive composition is improved. Furthermore, the resolution of the resist pattern is further improved, and changes in the line width of the resist pattern due to variations in the holding time from exposure to development can be suppressed, resulting in a radiation-sensitive composition with excellent process stability.

[0238] Examples of acid diffusion control agents (D) include compounds represented by the following formula (7) (hereinafter also referred to as "nitrogen-containing compounds (I)"), compounds having two nitrogen atoms in the same molecule (hereinafter also referred to as "nitrogen-containing compounds (II)"), compounds having three nitrogen atoms (hereinafter also referred to as "nitrogen-containing compounds (III)"), amide group-containing compounds, urea compounds, nitrogen-containing heterocyclic compounds, and the like.

[0239]

[0240] In the above formula (7), R ２２ , R ２３ and R ２４Each of these is independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.

[0241] Examples of nitrogen-containing compounds (I) include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; trialkylamines such as triethylamine and triamylamine; and aromatic amines such as aniline and 2,6-di-i-propylaniline.

[0242] Examples of nitrogen-containing compounds (II) include ethylenediamine, N,N,N',N'-tetramethylethylenediamine, and 1,1',1'',1''''-(ethylenedinitrilo)tetrakis(2-propanol).

[0243] Examples of nitrogen-containing compounds (III) include polyamine compounds such as polyethyleneimine and polyallylamine; and polymers such as dimethylaminoethylacrylamide.

[0244] Examples of amide group-containing compounds include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, propionamide, benzamide, pyrrolidone, and N-methylpyrrolidone.

[0245] Examples of urea compounds include urea, methyl urea, 1,1-dimethyl urea, 1,3-dimethyl urea, 1,1,3,3-tetramethyl urea, 1,3-diphenyl urea, and tributylthiourea.

[0246] Examples of nitrogen-containing heterocyclic compounds include pyridines such as pyridine, 2-methylpyridine, and 2,6-di-t-butylpyridine; morpholines such as N-propylmorpholine and N-(undecylcarbonyloxyethyl)morpholine; and pyrazines, pyrazoles, terpyridines, and 2-phenylbenzimidazole.

[0247] Furthermore, compounds having acid-dissociable groups can also be used as the nitrogen-containing organic compounds mentioned above. Examples of nitrogen-containing organic compounds having such acid-dissociable groups include N-t-butoxycarbonylpiperidine, 1-(tert-butoxycarbonyl)-4-hydroxypiperidine, N-t-butoxycarbonylimidazole, N-t-butoxycarbonylbenzimidazole, N-t-butoxycarbonyl-2-phenylbenzimidazole, N-(t-butoxycarbonyl)di-n-octylamine, N-(t-butoxycarbonyl)diethanolamine, N-(t-butoxycarbonyl)dicyclohexylamine, N-(t-butoxycarbonyl)diphenylamine, N-t-butoxycarbonyl-4-hydroxypiperidine, N-t-butoxycarbonyl-4-acetoxypiperidine, and N-t-amyloxycarbonyl-4-hydroxypiperidine.

[0248] Furthermore, as the acid diffusion control agent (D), an onium salt compound (d) that generates an acid with a higher pKa than the acid generated by the above-mentioned radiation-sensitive acid generator (A) or the radiation-sensitive acid generator (P) described later can also be suitably used.

[0249] The onium salt compound (d) is preferably represented by the following formulas (8-1) to (8-4).

[0250] In the above formulas (8-1) to (8-4), J ＋ It is a sulfonium cation, U ＋ This is an iodonium cation. - and Q - Each of them is independent of OH - It may be R α -O - , R α -COO - , R α -SO ３ - It may also be an organic acid anion represented by the above formulas (8-1) to (8-2), α R is a monovalent organic group having 1 to 30 carbon atoms. In the above formulas (8-3) to (8-4), αR is a single bond or a divalent organic group having 1 to 30 carbon atoms. As an example of the monovalent organic group having 1 to 30 carbon atoms, R in formula (a-1) above is... Ｘ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably adopted as a group with 1 to 30 carbon atoms. As the above-mentioned divalent organic group having 1 to 30 carbon atoms, a group obtained by removing one hydrogen atom from the above-mentioned monovalent organic group having 1 to 30 carbon atoms can be suitably adopted.

[0251] Examples of organic acid anions for the above-mentioned acid diffusion control agent include, but are not limited to, those listed below.

[0252]

[0253]

[0254] In the above acid diffusion control agent, radioactive onium cations are preferred, such as radiodegradable onium cations containing elements such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, and Bi. Examples of radiodegradable onium cations include sulfonium cations, iodonium cations, phosphonium cations, diazonium cations, and pyridinium cations. Among these, sulfonium cations or iodonium cations are preferred. Sulfonium cations or iodonium cations are preferably represented by the following formulas (X-1) to (X-6).

[0255]

[0256] In the above equation (X-1), R ａ１ , R ａ２ and R ａ３ Each of these independently comprises a substituted or unsubstituted linear or branched alkyl group, alkoxy group or alkoxycarbonyloxy group having 1 to 12 carbon atoms, a substituted or unsubstituted monocyclic or polycyclic cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, hydroxyl group, halogen atom, or -OSO ２ -R Ｐ , -SO ２ -R Ｑ , -S-R ＴR represents a ring structure consisting of -O-, -CO-, or a combination thereof, or two or more of these groups combined with each other. This ring structure may contain heteroatoms such as O or S between the carbon-carbon bonds forming the skeleton. Ｐ , R Ｑ and R Ｔ Each of these is independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k1, k2, and k3 are each independently integers from 0 to 5. R ａ１ ~R ａ３ And R Ｐ , R Ｑ and R Ｔ If each of them is multiple, then multiple R ａ１ ~R ａ３ And R Ｐ , R Ｑ and R Ｔ These may be the same or different.

[0257] In the above equation (X-2), R ｂ１ This is a substituted or unsubstituted linear or branched alkyl or alkoxy group having 1 to 20 carbon atoms, an alkoxyalkyloxy group, a substituted or unsubstituted acyl group having 2 to 8 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms, or a hydroxyl group. ｋ n is either 0 or 1. ｋ When is 0, k4 is an integer from 0 to 4, and n ｋ When k4 is 1, k4 is an integer from 0 to 7. ｂ１ If there are multiple R ｂ１ They may be the same or different, and there may be multiple R's. ｂ１ R may represent a ring structure formed by combining with other elements. ｂ２ This is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. Ｃ k5 is a single bond or a divalent linking group. k5 is an integer from 0 to 4. ｂ２ If there are multiple R ｂ２They may be the same or different, and there may be multiple R's. ｂ２ may represent a ring structure formed by combining with each other. q is an integer from 0 to 3. In the formula, S ＋ The ring structure containing may include heteroatoms such as O and S between the carbon-carbon bonds that form the skeleton.

[0258] In the above equation (X-3), R ｃ１ , R ｃ２ and R ｃ３ Each of these is independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms.

[0259] In the above equation (X-4), R ｇ１ This is a substituted or unsubstituted linear or branched alkyl or alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted acyl group having 2 to 8 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms, or a hydroxyl group. ｋ２ n is either 0 or 1. ｋ２ When is 0, k10 is an integer from 0 to 4, and n ｋ２ When is 1, k10 is an integer from 0 to 7. ｇ１ If there are multiple R ｇ１ They may be the same or different, and there may be multiple R's. ｇ１ R may represent a ring structure formed by combining with other elements. ｇ２ and R ｇ３ Each of these independently represents a substituted or unsubstituted linear or branched alkyl group, alkoxy group or alkoxycarbonyloxy group having 1 to 12 carbon atoms, a substituted or unsubstituted monocyclic or polycyclic cycloalkyl group having 3 to 12 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group, hydroxyl group, halogen atom having 6 to 12 carbon atoms, or a ring structure formed by combining these groups. k11 and k12 are each independently integers from 0 to 4. R ｇ２ and R ｇ３ If each of them is multiple, then multiple R ｇ２ and R ｇ３ These may be the same or different.

[0260] In the above equation (X-5), R ｄ１and R ｄ２ Each of these independently represents a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, an alkoxy group or alkoxycarbonyl group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms, a halogen atom, a halogenated alkyl group having 1 to 4 carbon atoms, a nitro group, or a ring structure formed by two or more of these groups combined. k6 and k7 are each independently integers from 0 to 5. R ｄ１ and R ｄ２ If each of them is multiple, then multiple R ｄ１ and R ｄ２ These may be the same or different.

[0261] In the above formula (X-6), R ｅ１ and R ｅ２ k8 and k9 are each independently a halogen atom, a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 12 carbon atoms.

[0262] Specific examples of the above-mentioned radiation-sensitive onium cation include, but are not limited to, the structure shown in the following formula.

[0263] (In the formula, tBu represents a t-butyl group and Me represents a methyl group.)

[0264]

[0265]

[0266]

[0267] The above acid diffusion control agent (d) can also be synthesized by known methods, particularly by salt exchange reactions.

[0268] These acid diffusion control agents (D) may be used individually or in combination of two or more.

[0269] When the above radiation-sensitive composition contains an acid diffusion control agent (D), the lower limit of the content of the acid diffusion control agent (D) (total in the case of multiple types) is preferably 0.01 parts by mass, more preferably 0.1 parts by mass, and still more preferably 1 part by mass, per 100 parts by mass of polymer (B). The upper limit of the above content is preferably 60 parts by mass, more preferably 50 parts by mass, and still more preferably 40 parts by mass. This allows for excellent sensitivity and pattern-forming properties during resist pattern formation.

[0270] <Radiation-sensitive acid generator (P)> The above-mentioned radiation-sensitive composition may also be used in combination with other radiation-sensitive acid generators (P) along with the above-mentioned radiation-sensitive acid generator (A). Examples of the above-mentioned radiation-sensitive acid generator (P) include nonionic radiation-sensitive acid generators (P1) (excluding those corresponding to the above-mentioned radiation-sensitive acid generator (A)) and ionic radiation-sensitive acid generators (P2).

[0271] Examples of the above-mentioned nonionic radioactive acid generator (P1) include the compound represented by the following formula (P1-1), the compound represented by the following formula (P1-2), and the compound represented by the following formula (P1-3).

[0272] (In the above formula (P1-1), R ５１ R is a divalent hydrocarbon group having 1 to 10 carbon atoms. ５２ (This refers to a monovalent organic group having 1 to 20 carbon atoms.)

[0273] (In the above formula (P1-2), R ５３ These are, independently, monovalent organic groups having 1 to 20 carbon atoms.

[0274] (In the above formula (P1-3), R ５４ R is a monovalent organic group having 1 to 20 carbon atoms. ５５ and R ５６ Each of these is independently a monovalent organic group having 1 to 20 carbon atoms, or R ５５ and R ５６ (These atoms are combined with each other and, together with the carbon atoms they bond to, form a cyclic structure.)

[0275] The above R５１ As a divalent hydrocarbon group having 1 to 10 carbon atoms, R in the above formula (a-1) is Ｘ Among the monovalent hydrocarbon groups having 1 to 20 carbon atoms, groups obtained by removing one hydrogen atom from the corresponding carbon number group can be suitably adopted. Among these, R ５１ Preferably, the alkylene group has 1 to 3 carbon atoms, or a cycloalkylene group containing a cyclic skeleton with unsaturated bonds.

[0276] The above R ５２ As a monovalent organic group having 1 to 20 carbon atoms, R in the above formula (a-1) is Ｘ A monovalent organic group having 1 to 20 carbon atoms, represented by R, can be suitably used. ５２ Preferably, the structure has at least one structure selected from the group consisting of an alicyclic structure, an ester bond, and a halogen atom.

[0277] The above R ５３ As a monovalent organic group having 1 to 20 carbon atoms, R in the above formula (a-1) is Ｘ A monovalent organic group having 1 to 20 carbon atoms, represented by R, can be suitably used. ５３ Preferably, it has at least one structure selected from the group consisting of an alicyclic structure and an ether bond.

[0278] The above alicyclic structure is R in formula (a-1) above. Ｘ A structure corresponding to a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms can be suitably adopted.

[0279] The above R ５４ ~R ５６ As a monovalent organic group having 1 to 20 carbon atoms represented by the above formula (a-1), R Ｘ A monovalent organic group having 1 to 20 carbon atoms, represented by [formula], can be suitably used.

[0280] R ５５ and R ５６ The cyclic structure formed when these elements are combined with the carbon atoms to which they bond can preferably be the cyclic structure described in formula (2) above.

[0281] Examples of compounds represented by the above formulas (P1-1) to (P1-3) include the following structures.

[0282] The above-mentioned ionic radioactive acid generator (P2) is a compound having an organic acid anion and an onium cation, which generates an acid capable of dissociating the above-mentioned acid-dissociable group upon exposure.

[0283] Examples of organic acid anions include sulfonic acid anions, sulfonimide anions, and sulfonmethide anions.

[0284] Examples of such acids include: (1) compounds in which one or more fluorine atoms, fluorinated hydrocarbon groups, or cyano groups are substituted on the α or β carbon atoms of a sulfo group, or in which an ester bond is interposed between carbon atoms; (2) compounds having a sulfonimide structure containing a fluorine atom; and (3) compounds having a sulfonemethide structure containing a fluorine atom.

[0285] The radiation-sensitive acid generator (P2) is preferably a compound represented by the following formula (P2). (In formula (P2), R ４ｚ It is a monovalent organic group having 2 to 40 carbon atoms. However, -SO ３ - A fluorine atom, a cyano group, or a monovalent fluorinated hydrocarbon group is bonded to the carbon atom at the α or β position relative to the sulfur atom in the molecule. ＋ (This is an onium cation.)

[0286] R ４ｚ As a monovalent organic group having 2 to 40 carbon atoms represented by the above formula (a-1), R Ｘ A monovalent organic group having 1 to 20 carbon atoms, represented by [the formula shown], can be suitably adopted as a group with an extended number of carbon atoms, ranging from 2 to 40.

[0287] R ４ｚIt is preferable that the is a monovalent organic group having 4 to 40 carbon atoms that includes at least one structure selected from the group consisting of a cyclic structure, a carbonyl group, and an ether bond. As such an organic group, a monovalent organic group having 4 to 40 carbon atoms that includes at least one structure selected from the group consisting of a cyclic structure, a carbonyl group, and an ether bond as described in formula (2) above can be suitably adopted.

[0288] The above monovalent fluorinated hydrocarbon group is R of formula (a-1) above. Ｘ In this material, a monovalent hydrocarbon group having 1 to 20 carbon atoms can be preferably used in which some or all of the hydrogen atoms are replaced with fluorine atoms.

[0289] Za ＋ Examples of onium cations represented by this formula include sulfonium cations and iodonium cations. The sulfonium cations and iodonium cations described in the above-mentioned acid diffusion control agent (d) can be suitably used.

[0290] Specific examples of the radiation-sensitive acid generator (P2) include, but are not limited to, structures represented by the following formula. A configuration in which an organic acid anion and an onium cation are covalently bonded is also shown.

[0291]

[0292]

[0293]

[0294]

[0295] In the present invention, the above-mentioned radiation-sensitive acid generator (P) can be used alone or in combination of two or more types.

[0296] If the above-mentioned radiation-sensitive composition contains a radiation-sensitive acid generator (P), the lower limit of the content of the radiation-sensitive acid generator (P) (total in the case of multiple types) is preferably 0.1 parts by mass, more preferably 0.5 parts by mass, and even more preferably 1 part by mass, per 100 parts by mass of polymer (B). The upper limit of the above content is preferably 30 parts by mass, more preferably 20 parts by mass, and even more preferably 10 parts by mass.

[0297] <Solvent (E)> The above radiation-sensitive composition contains solvent (E). Solvent (E) is not particularly limited as long as it is a solvent capable of dissolving or dispersing the radiation-sensitive acid generator (A) and the base polymer (B), as well as any optional components that may be included if desired.

[0298] Examples of solvents (E) include alcohol-based solvents, ether-based solvents, ketone-based solvents, amide-based solvents, ester-based solvents, hydrocarbon-based solvents, and the like.

[0299] Examples of alcohol-based solvents include monoalcohol solvents having 1 to 18 carbon atoms, such as isopropanol, 4-methyl-2-pentanol, n-hexanol, 2-ethylhexanol, furfuryl alcohol, cyclohexanol, 3,3,5-trimethylcyclohexanol, and diacetone alcohol; polyhydric alcohol solvents having 2 to 18 carbon atoms, such as ethylene glycol, 1,2-propylene glycol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, and tripropylene glycol; and polyhydric alcohol partial ether solvents, such as 3-methoxybutanol and 1-methoxy-2-propanol (propylene glycol monomethyl ether), which are obtained by etherifying some of the hydroxyl groups in the above-mentioned polyhydric alcohol solvents.

[0300] In this embodiment, alcohol acid ester solvents such as methyl lactate, ethyl lactate, propyl lactate, butyl lactate, methyl 2-hydroxyisobutyrate, isopropyl 2-hydroxyisobutyrate, isobutyl 2-hydroxyisobutyrate, and n-butyl 2-hydroxyisobutyrate are also included in the alcohol-based solvents.

[0301] Examples of ether-based solvents include dialkyl ether solvents such as diethyl ether, dipropyl ether, and dibutyl ether; cyclic ether solvents such as tetrahydrofuran and tetrahydropyran; aromatic ring-containing ether solvents such as diphenyl ether and anisole (methylphenyl ether); and polyhydric alcohol ether solvents in which the hydroxyl groups of the above-mentioned polyhydric alcohol solvents, such as propylene glycol monomethyl ether, have been etherified.

[0302] Examples of ketone solvents include linear ketone solvents such as acetone, butanone, and methyl isobutyl ketone; cyclic ketone solvents such as cyclopentanone, cyclohexanone, and methylcyclohexanone; and 2,4-pentanedione, acetonylacetone, and acetophenone.

[0303] Examples of amide solvents include cyclic amide solvents such as N,N'-dimethylimidazolidinone and N-methylpyrrolidone; and chain-like amide solvents such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, and N-methylpropionamide.

[0304] Examples of ester solvents include monocarboxylic acid ester solvents such as n-butyl acetate and methyl 3-methoxypropionate; polyhydric alcohol partial ether acetate solvents such as diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, and dipropylene glycol monomethyl ether acetate; lactone solvents such as γ-butyrolactone and valerolactone; carbonate solvents such as diethyl carbonate, ethylene carbonate, and propylene carbonate; and polyhydric carboxylic acid diester solvents such as propylene glycol diacetate, methoxytriglycol acetate, diethyl oxalate, ethyl acetoethyl acetate, and diethyl phthalate.

[0305] Examples of hydrocarbon solvents include aliphatic hydrocarbon solvents such as n-hexane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, diisopropylbenzene, and n-amylnaphthalene.

[0306] Among these, alcohol-based solvents, ester-based solvents, and ketone-based solvents are preferred, alcoholic acid ester-based solvents, monoalcohol-based solvents having 1 to 18 carbon atoms, polyhydric alcohol partial ether acetate-based solvents, polyhydric alcohol partial ether-based solvents, and lactone-based solvents are more preferred, and ethyl lactate, methyl 3-methoxypropionate, cyclohexanenone, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, and γ-butyrolactone are even more preferred. The radiation-sensitive composition may contain one or more solvents.

[0307] <Other Optional Components> The above-mentioned radiation-sensitive composition may contain other optional components in addition to the components listed above. Examples of these other optional components include segregation accelerators, dissolution accelerators, surfactants, alicyclic skeleton-containing compounds, sensitizers, etc. These other optional components may be used individually or in combination of two or more types.

[0308] The surfactants mentioned above are not particularly limited, but non-fluorinated surfactants or non-silicone surfactants can be suitably used.

[0309] If the above radiation-sensitive composition contains the above optional component, the content of the above optional component is preferably 0.01 parts by mass or more, more preferably 0.03 parts by mass or more, per 100 parts by mass of the above base polymer (B). Furthermore, it is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less.

[0310] <Method for preparing a radiation-sensitive composition> The above radiation-sensitive composition can be prepared by mixing, for example, a radiation-sensitive acid generator (A), a polymer (B), a solvent (E), and optionally a crosslinking agent (Q), an acid diffusion control agent (D), a radiation-sensitive acid generator (P), etc., in predetermined proportions. After mixing, the above radiation-sensitive composition is preferably filtered using, for example, a filter with a pore size of about 0.05 μm to 0.40 μm. The solid content concentration of the above radiation-sensitive composition is usually 0.1% to 50% by mass, preferably 0.5% to 30% by mass, and more preferably 1% to 20% by mass.

[0311] ≪Pattern Forming Method≫ A pattern forming method according to one embodiment of the present invention includes the steps of: (1) applying the above-mentioned radiation-sensitive composition directly or indirectly to a substrate to form a resist film (hereinafter also referred to as the "resist film forming step"); (2) exposing the resist film (hereinafter also referred to as the "exposure step"); and (3) developing the exposed resist film with a developer (hereinafter also referred to as the "development step").

[0312] According to the pattern formation method described above, since the radiation-sensitive composition that exhibits excellent sensitivity, exposure margin, depth of field, pattern rectangularity, pattern circularity, CDU, LWR, and defect suppression is used during pattern formation, high-quality resist patterns can be efficiently formed. Each step will be described below.

[0313] [Resist Film Formation Process] In this process (step (1) above), a resist film is formed using the radiation-sensitive composition. Examples of substrates for forming this resist film include conventionally known materials such as silicon wafers, silicon dioxide wafers, and aluminum-coated wafers. Alternatively, an organic or inorganic anti-reflective film disclosed in, for example, Japanese Patent Publication No. 6-12452 or Japanese Patent Publication No. 59-93448 may be formed on the substrate. Examples of coating methods include spin coating, casting, and roll coating. After coating, pre-baking (PB) may be performed as needed to volatilize the solvent in the coating film. The PB temperature is usually 60°C to 170°C, with 80°C to 150°C being preferred. The PB time is usually 5 seconds to 600 seconds, with 10 seconds to 300 seconds being preferred.

[0314] The lower limit of the thickness of the formed resist film is preferably 10 nm, more preferably 15 nm, and even more preferably 20 nm. The upper limit of the thickness is preferably 9000 nm, and more preferably 4000 nm. In particular, when a thick resist film is exposed to KrF excimer laser light in the exposure process described later, the lower limit of the thickness may be 100 nm, 150 nm, or 200 nm.

[0315] When performing immersion exposure, regardless of whether or not the above-mentioned high-fluorine-content polymer additive is present in the radiation-sensitive composition, a protective immersion film insoluble in the immersion liquid may be provided on the formed resist film to avoid direct contact between the immersion liquid and the resist film. As the protective immersion film, either a solvent-peelable protective film that is peeled off with a solvent before the development process (see, for example, Japanese Patent Application Publication No. 2006-227632) or a developer-peelable protective film that is peeled off simultaneously with development in the development process (see, for example, International Publication No. 2005 / 069076 and International Publication No. 2006 / 035790) may be used. However, from the viewpoint of throughput, it is preferable to use a developer-peelable protective immersion film.

[0316] [Exposure Process] In this process (process (2) above), the resist film formed in the resist film formation process, which is process (1) above, is exposed by irradiating it with radiation through a photomask (and, in some cases, through an immersion liquid such as water). Examples of radiation used for exposure include electromagnetic waves such as visible light, ultraviolet light, far ultraviolet light, EUV (extreme ultraviolet light), X-rays, and gamma rays, depending on the line width of the desired pattern; and charged particle beams such as electron beams and alpha rays. Among these, the radiation-sensitive composition of the present invention is preferably exposed to ultraviolet light, far ultraviolet light, electron beams, and EUV, and more preferably to ArF excimer laser light (wavelength 193 nm), KrF excimer laser light (wavelength 248 nm), i-rays, and EUV.

[0317] When exposure is performed by immersion lithography, the immersion liquid used can be, for example, water or a fluorine-based inert liquid. The immersion liquid is preferably transparent to the exposure wavelength and has the smallest possible temperature coefficient of refractive index to minimize distortion of the optical image projected onto the film. In particular, when the exposure light source is ArF excimer laser light (wavelength 193 nm), in addition to the above considerations, water is preferred due to its availability and ease of handling. When water is used, a small amount of an additive that reduces the surface tension of the water and increases its surfactant properties may be added. This additive is preferably one that does not dissolve the resist film on the wafer and has negligible effect on the optical coating on the underside of the lens. Distilled water is preferred as the water used.

[0318] After the exposure described above, post-exposure baking (PEB) is performed to promote the dissociation of acid-dissociable groups in polymers, etc., by the acid generated from the radiation-sensitive acid generator (A) or radiation-sensitive acid generator (P) by exposure in the exposed portion of the resist film, and to promote the crosslinking reaction of polymers by the crosslinking agent. This PEB creates a difference in solubility in the developer between the exposed and unexposed portions. The PEB temperature is usually 60°C to 160°C, with 80°C to 140°C being preferred. The PEB time is usually 5 seconds to 600 seconds, with 10 seconds to 300 seconds being preferred.

[0319] [Development Process] In this process (step (3) above), the resist film exposed in the exposure process, which is step (2) above, is developed. This allows a predetermined resist pattern to be formed. After development, it is common to wash with a rinsing solution such as water or alcohol and then dry it.

[0320] Examples of developers used in the above development process include, in the case of alkaline development, an alkaline aqueous solution containing at least one alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH), pyrrole, piperidine, choline, 1,8-diazabicyclo-[5.4.0]-7-undecene, and 1,5-diazabicyclo-[4.3.0]-5-nonene. Among these, an aqueous TMAH solution is preferred, and a 2.38% by mass aqueous TMAH solution is more preferred.

[0321] Furthermore, in the case of organic solvent development, examples of organic solvents include hydrocarbon solvents, ether solvents, ester solvents, ketone solvents, alcohol solvents, or solvents containing organic solvents. Examples of the above organic solvents include one or more of the solvents listed above as solvents for the radiation-sensitive composition. Among these, ether solvents, ester solvents, and ketone solvents are preferred. As for ether solvents, glycol ether solvents are preferred, and ethylene glycol monomethyl ether and propylene glycol monomethyl ether are more preferred. As for ester solvents, acetate ester solvents are preferred, and n-butyl acetate and amyl acetate are more preferred. As for ketone solvents, chain ketones are preferred, and 2-heptanone is more preferred. The content of organic solvents in the developer is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 99% by mass or more. Examples of components other than organic solvents in the developer include water and silicone oil.

[0322] As mentioned above, either an alkaline developer or an organic solvent developer may be used as the developer. The appropriate choice can be made depending on whether a positive or negative pattern is desired.

[0323] Examples of development methods include immersing the substrate in a tank filled with developer solution for a certain period of time (dip method), developing by puddling the developer solution onto the substrate surface using surface tension and letting it remain still for a certain period of time (paddle method), spraying the developer solution onto the substrate surface (spray method), and continuously dispensing the developer solution while scanning a developer solution dispensing nozzle at a constant speed onto a substrate rotating at a constant speed (dynamic dispensing method).

[0324] ≪Compound≫ A compound according to one embodiment of the present invention is represented by any of the following formulas: (1), (2'), and (3). (In equations (1), (2'), and (3), R １ and R ２ Each of these is independently either a cyano group, a nitro group, a monovalent organic group having 1 to 20 carbon atoms, or R １ and R ２ These atoms are combined with each other and, together with the atoms they bond to, form a cyclic structure. ３ R is a monovalent organic group having 1 to 20 carbon atoms. ａ This is a group represented by the following formula (a-1). (In formula (a-1), R Ｘ R is a monovalent organic group having one or more carbon atoms. L is a single bond or a divalent linking group. ｆ１ and R ｆ２ These are, independently, a hydrogen atom, -CN, and -NO. ２ -F, -CF ２ R ｔ１ , -SO ２ R ｔ２ ,-COR ｔ３ , or -CF ２ R ｔ１ , -SO ２ R ｔ２ ,-COR ｔ３ Or -CF ３ (a) is a monovalent organic group with 1 to 20 carbon atoms other than R.ｔ１ R is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. ｔ２ and R ｔ３ Each of these is independently a monovalent organic group having 1 to 20 carbon atoms. ｆ１ and R ｆ２ If multiple R ｆ１ and R ｆ２ These are either the same or different. n is an integer from 1 to 5. * represents a bond with a sulfur atom in formula (1) or formula (3). However, R ｆ１ and R ｆ２ At least one of them is -CN, -NO ２ -F, -CF ２ R ｔ１ , -SO ２ R ｔ２ , or -COR ｔ３ and one or more R ｆ１ If R is -F, then R is -F. ｆ１ R bonded to the carbon atom to which it is attached. ｆ２ is a group other than -F, and R ｆ１ and R ｆ２ At least one of them is -CN or -SO ２ R ｔ２ If R Ｘ is a hydrogen atom, or a monovalent organic group having one or more carbon atoms, R ｆ１ and R ｆ２ However, -CN or -SO ２ R ｔ２ For groups other than R Ｘ (This is a monovalent organic group with one or more carbon atoms.) ａ１ This is a group represented by the following formula (a-11). (In formula (a-11), R Ｘ１ L, R are monovalent organic groups having one or more carbon atoms. ｆ１ , R ｆ２ And n are equivalent to the above formula (a-1). However, R ｆ１ and R ｆ２ At least one of them is -CN, -NO ２ -F, -CF ２ R ｔ１ , -SO ２ R ｔ２, or -COR ｔ３ and one or more R ｆ１ If R is -F, then R is -F. ｆ１ R bonded to the carbon atom to which it is attached. ｆ２ This is a group other than -F.

[0325] Examples of such compounds include those corresponding to formulas (1), (2'), and (3) in the radiation-sensitive acid generator (A) of the above-mentioned radiation-sensitive composition.

[0326] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. The methods for measuring various physical properties are shown below.

[0327] [Weight-average molecular weight (Mw) and number-average molecular weight (Mn)] The Mw and Mn of the polymer were measured under the conditions described above. The degree of dispersion (Mw / Mn) was calculated from the measured results of Mw and Mn.

[0328] [ １３ [C-NMR analysis] Polymer １３ C-NMR analysis was performed using a nuclear magnetic resonance spectrometer (JEOL Ltd.'s "JNM-Delta400").

[0329] <Synthesis of Polymers> The monomers used in the synthesis of each polymer in each example and comparative example are shown below. In the following synthesis examples, unless otherwise specified, parts by mass refers to the value when the total mass of the monomers used is 100 parts by mass, and mol% refers to the value when the total number of moles of the monomers used is 100 mol%.

[0330]

[0331] [Synthesis Example 1] (Synthesis of Polymer (B-1)) Monomer (M-1), monomer (M-5), monomer (M-9), and monomer (M-12) were dissolved in 1-methoxy-2-propanol (200 parts by mass) in a molar ratio of 50 / 10 / 35 / 5 (mol%), and AIBN (azobisisobutyronitrile) (5 mol% relative to the total 100 mol% of monomers used) was added as an initiator to prepare a monomer solution. 100 parts by mass of 1-methoxy-2-propanol was placed in a reaction vessel, and after purging with nitrogen for 30 minutes, the reaction vessel was heated to 80°C, and the monomer solution was added dropwise over 3 hours while stirring. The start of the dropwise addition was defined as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours. After the polymerization reaction was completed, the polymerization solution was cooled with water to below 30°C. The cooled polymerization solution was added to methanol (2,000 parts by mass), and the precipitated white powder was filtered off. The filtered white powder was washed twice with methanol, filtered again, and dissolved in 1-methoxy-2-propanol (300 parts by mass). Then, 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 with stirring. After the reaction was complete, the residual solvent was removed by distillation, and the resulting solid was dissolved in acetone (100 parts by mass) and added dropwise to hexane (500 parts by mass) to solidify the polymer. The resulting solid was filtered and dried at 50°C for 13 hours to obtain a white powdery polymer (B-1) (yield: 85%). The Mw of polymer (B-1) was 6,700, and the Mw / Mn ratio was 1.34. １３ ¹³C-NMR analysis revealed that the content of each structural unit derived from (M-1), (M-5), (M-9), and (M-12) was 50.2 mol%, 9.9 mol%, 36.0 mol%, and 3.9 mol%, respectively. Furthermore, in the monomer that gives structural unit (II-1), in the polymer, １３ 13C-NMR analysis confirmed the disappearance of the carbonyl group peak of the acetyl group, indicating that virtually all alkali-dissociable groups had been hydrolyzed to form phenolic hydroxyl groups.

[0332] [Synthesis Examples 2-8] (Synthesis of Polymers (B-2) to (B-8)) Polymers (B-2) to (B-8) were synthesized in the same manner as in Synthesis Example 1, except that monomers of the types and proportions shown in Table 1 below were used. Note that in the monomer that gives structural unit (II-1), in the polymer, １３ 13C-NMR analysis confirmed the disappearance of the carbonyl group peak of the acetyl group, indicating that virtually all alkali-dissociable groups had been hydrolyzed to phenolic hydroxyl groups. The content percentage (mol%) and physical properties (Mw and Mw / Mn) of each structural unit of the obtained polymer are shown in Table 1 below. In Table 1, "-" indicates that the corresponding component was not used (the same applies to subsequent tables).

[0333]

[0334] [Synthesis Example 9] (Synthesis of Polymer (B-9)) Monomer (M-10), monomer (M-13), and monomer (M-15) were dissolved in 2-butanone (200 parts by mass) in a molar ratio of 40 / 50 / 10 (mol%), and AIBN (7 mol% relative to the total 100 mol% of monomers used) was added as an initiator to prepare a monomer solution. 100 parts by mass of 1-methoxy-2-propanol was placed in the reaction vessel, and after purging with nitrogen for 30 minutes, the temperature inside the reaction vessel was raised to 80°C, and the monomer solution was added dropwise over 3 hours while stirring. The start of the dropwise addition was defined as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours. After the polymerization reaction was completed, the polymerization solution was cooled with water to below 30°C. The cooled polymerization solution was added to methanol (2,000 parts by mass), and the precipitated white powder was filtered off. The filtered white powder was washed twice with methanol, filtered again, and dried at 50°C for 24 hours to obtain a white powdery polymer (B-9) (yield: 85%). The Mw of polymer (B-9) was 6,100, and the Mw / Mn ratio was 1.51. １３ ¹³C-NMR analysis revealed that the content of each structural unit derived from (M-10), (M-13), and (M-15) was 39.4 mol%, 51.1 mol%, and 9.5 mol%, respectively.

[0335] [Synthesis Example 10] (Synthesis of high-fluorine-content polymer (F-1)) Monomer (M-10), monomer (M-12), and monomer (M-16) were dissolved in 2-butanone (200 parts by mass) in a molar ratio of 55 / 5 / 40 (mol%), and AIBN (2 mol%) was added as an initiator to prepare monomer solutions. 2-butanone (100 parts by mass) was placed in a reaction vessel, and after purging with nitrogen for 30 minutes, the temperature inside the reaction vessel was set to 80°C, and the monomer solutions were added dropwise over 3 hours while stirring. The start of the dropwise addition was defined as the start time of the polymerization reaction, and the polymerization reaction was carried out for 6 hours. After the polymerization reaction was completed, the polymerization solution was cooled to below 30°C by water cooling. The solvent was replaced with acetonitrile (400 parts by mass), and hexane (100 parts by mass) was added and stirred, and the acetonitrile layer was recovered. This process was repeated three times. By substituting the solvent with propylene glycol monomethyl ether acetate, a solution of the high-fluorine-content polymer (F-1) was obtained (yield: 75%). The Mw of the high-fluorine-content polymer (F-1) was 13,200, and the Mw / Mn ratio was 1.80. １３ 13C-NMR analysis revealed that the content of each structural unit derived from (M-10), (M-12), and (M-16) was 53.2 mol%, 6.2 mol%, and 40.6 mol%, respectively.

[0336] <Synthesis of Compound (A) (Radiation-Sensitive Acid Generator)> [Example A1] (Synthesis of Compound (A-1)) Compound (A-1) as a radiation-sensitive acid generator (A) was synthesized according to the following synthesis scheme.

[0337]

[0338] 20.0 mmol of ethyl cyanoethyl, 25.0 mmol of bromine, and 50 g of dichloromethane were added to a reaction vessel and stirred at room temperature for 5 hours. Then, saturated sodium thiosulfate aqueous solution was added to the reaction solution to terminate the reaction, and dichloromethane was added for extraction, separating the organic layer. The obtained organic layer was washed with saturated sodium chloride aqueous solution, and then with water. After drying with sodium sulfate, the solvent was removed by distillation, and the bromo compound was obtained in good yield by column chromatography.

[0339] To the above brominated product, a mixture of acetonitrile and water (1:1 by mass) was added to make a 1 M solution. Then, 40.0 mmol of sodium dithionite and 60.0 mmol of sodium bicarbonate were added, and the mixture was reacted at 70°C for 4 hours. After extraction with acetonitrile and removal of the solvent by distillation, a mixture of acetonitrile and water (3:1 by mass) was added to make a 0.5 M solution. 60.0 mmol of hydrogen peroxide and 2.00 mmol of sodium tungstate were added, and the mixture was heated and stirred at 50°C for 12 hours. By extraction with acetonitrile and removal of the solvent by distillation, the sodium sulfonate salt was obtained in good yield.

[0340] 40.0 mmol of thionyl chloride, 0.04 mmol of dimethylformamide, and 10 g of acetonitrile were added to the above sodium sulfonate salt and the mixture was stirred at 100°C for 12 hours. The solvent and thionyl chloride were then removed by distillation to obtain a sulfonate chloride compound. 20.0 mmol of N-hydroxysuccinimide, 40.0 mmol of pyridine, and 50 g of dichloromethane were added to the above sulfonate chloride compound and the mixture was stirred at 40°C for 3 hours. Then, saturated ammonium chloride aqueous solution was added to the reaction solution to terminate the reaction, and dichloromethane was added for extraction, separating the organic layer. The obtained organic layer was washed with saturated sodium chloride aqueous solution, and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the compound (A-1) represented by the above formula (A-1) was purified by column chromatography in good yield.

[0341] [Examples A2 to A10, A17] (Synthesis of compounds (A-2) to (A-10), (A-17)) Compounds as radiation-sensitive acid generators represented by the following formulas (A-2) to (A-10), (A-17) were synthesized in the same manner as in Example A1, except that the raw materials and precursors were appropriately changed.

[0342]

[0343] [Example A11] (Synthesis of compound (A-11)) Compound (A-11) as a radiation-sensitive acid generator (A) was synthesized according to the following synthesis scheme.

[0344]

[0345] 20.0 mmol of ethyl bromofluoroethyl, 25.0 mmol of α-hydroxy-γ-butyrolactone, 2.0 mmol of p-toluenesulfonic acid, and toluene were added to a reaction vessel and stirred at 100°C for 12 hours. Then, saturated sodium bicarbonate aqueous solution was added to the reaction solution to terminate the reaction, followed by extraction with ethyl acetate to separate the organic layer. The obtained organic layer was washed with saturated sodium bicarbonate aqueous solution and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the lactone was purified by column chromatography to obtain the lactone in good yield.

[0346] The lactone mixture was mixed with 25.0 mmol of zinc powder, 2.00 mmol of chlorotrimethylsilane, and 50 g of tetrahydrofuran, and stirred at room temperature for 1 hour. Then, 30.0 mmol of colloidal sulfur was added to the reaction solution and stirred at room temperature for a further 6 hours. After that, saturated aqueous ammonium chloride solution was added to the reaction solution to terminate the reaction, and then ethyl acetate was added for extraction, separating the organic layer. The obtained organic layer was washed with saturated aqueous sodium chloride solution, and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the thiol compound was obtained in good yield by column chromatography.

[0347] 30.0 mmol of sodium hydride, 10.0 mmol of dichloromethane, and 50 g of tetrahydrofuran were added to the above thiol mixture and the mixture was stirred at room temperature for 12 hours. Then, saturated aqueous ammonium chloride solution was added to the reaction solution to terminate the reaction, and ethyl acetate was added for extraction, separating the organic layer. The obtained organic layer was washed with saturated aqueous sodium chloride solution, and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the compound (A-11-a) was obtained in good yield by column chromatography.

[0348] To the above compound (A-11-a), 100.0 mmol of metachloroperbenzoic acid and 50 g of dichloromethane were added and the mixture was stirred at room temperature for 24 hours. Then, saturated sodium sulfite aqueous solution was added to the reaction solution to terminate the reaction, and dichloromethane was added for extraction, separating the organic layer. The obtained organic layer was washed with saturated sodium bicarbonate aqueous solution, saturated sodium chloride aqueous solution, and then water. After drying with sodium sulfate, the solvent was removed by distillation, and the compound (A-11-b) was obtained in good yield by purification by column chromatography.

[0349] To the above compound (A-11-b), 20.0 mmol of 1,8-diazabicyclo[5.4.0]-7-undecene (DBU), 20.0 mmol of tosyl azide, and 50 g of dichloromethane were added and the mixture was stirred at room temperature for 24 hours. Then, saturated aqueous ammonium chloride solution was added to the reaction solution to terminate the reaction, and dichloromethane was added for extraction, after which the organic layer was separated. The obtained organic layer was washed with saturated aqueous sodium chloride solution and then with water. After drying over sodium sulfate, the solvent was removed by distillation, and the compound (A-11) represented by the above formula (A-11) was obtained in good yield by purification by column chromatography.

[0350] [Examples A12 to A16] (Synthesis of compounds (A-12) to (A-15) and (A-16)) Compounds as radiation-sensitive acid generators represented by the following formulas (A-12) to (A-15) and (A-16) were synthesized in the same manner as in Example A11, except that the raw materials and precursors were appropriately changed.

[0351]

[0352] In addition to the synthesized components mentioned above, the following compounds were used.

[0353] [Polymers other than polymers (B-1) to (B-8)] B-i-1 to B-i-2: Polymers represented by the following formulas (B-i-1) to (B-i-2) (Hereafter, polymers represented by formulas (B-i-1) to (B-i-2) may be referred to as "polymer (B-i-1)" to "polymer (B-i-2)," respectively.)

[0354]

[0355] [Radiation-sensitive acid generators other than (A-1) to (A-17)] a-1 to a-6: Compounds represented by the following formulas (a-1) to (a-6) (Hereafter, compounds represented by formulas (a-1) to (a-6) may be referred to as "compound (a-1)" to "compound (a-6)," respectively.)

[0356]

[0357] [Acid Diffusion Control Agent (D)] D-1 to D-5: Compounds represented by the following formulas (D-1) to (D-5) (Hereafter, the compounds represented by formulas (D-1) to (D-5) may be referred to as "Compound (D-1)" to "Compound (D-5)," respectively.)

[0358]

[0359] [Crosslinking agent (Q)] Q-1 to Q-3: Compounds represented by the following formulas (Q-1) to (Q-3) (Hereafter, compounds (Q-1) to (Q-3) may be referred to as "compound (Q-1)" to "compound (Q-3)," respectively.)

[0360]

[0361] [Other Additives (W)] W-1 to W-5: Compounds represented by the following formulas (W-1) to (W-3) and additive compounds (W-4) to (W-5) (Hereinafter, compounds (W-1) to (W-5) may be referred to as "compound (W-1)" to "compound (W-5)," respectively.)

[0362]

[0363] W-4: MEGAFACE EFS-321 (manufactured by DIC Corporation) (non-fluorine-based) W-5: BYK-399 (manufactured by Big Chemie Japan Co., Ltd.) (non-silicone-based)

[0364] [Solvent (E)] E-1: Propylene glycol monomethyl ether acetate E-2: Propylene glycol monomethyl ether E-3: Ethyl lactate E-4: Methyl 3-methoxypropionate E-5: Cyclohexanone

[0365] [Preparation of positive-type radiation-sensitive composition for KrF exposure] [Example 1] A radiation-sensitive composition (J-1) was prepared by mixing 100 parts by mass of (B-1) as polymer (B), 12.0 parts by mass of (A-1) as a radiation-sensitive acid generator (compound (A)), 3.0 parts by mass of (D-1) as an acid diffusion control agent (D), 0.05 parts by mass of (W-1) as other additive (W), and 300 parts by mass of a mixed solvent of (E-1) / (E-3) as solvent (E), and filtering the mixture through a membrane filter with a pore size of 0.2 μm.

[0366] [Examples 2-33, 101-102, and Comparative Examples 1-3] Radiation-sensitive compositions (J-2)-(J-33), (J-101)-(J-102), and (CJ-1)-(CJ-3) were prepared in the same manner as in Example 1, except that the components of the types and amounts shown in Table 2 below were used.

[0367]

[0368] <Formation of a resist pattern using a positive-type radiation-sensitive composition for KrF exposure> The prepared positive-type radiation-sensitive composition for KrF exposure was applied to a 12-inch silicon wafer treated with hexamethyldisilazane using a spin coater (CLEAN TRACK ACT12 from Tokyo Electron Limited), and pre-bake (PB) was performed at 130°C for 60 seconds. Subsequently, a resist film with an average thickness of 1000 nm was formed by cooling at 23°C for 30 seconds. Next, this resist film was exposed using a KrF excimer laser scanner (PAS5500 / 850C wavelength 248 nm from ASML) under optical conditions of NA = 0.69 and σ = 0.70, through a 400 nm line-and-space mask pattern. After exposure, post-exposure bake (PEB) was performed at 130°C for 60 seconds. Subsequently, the resist film was alkaline-developed using a 2.38% by mass aqueous solution of TMAH as the alkaline developer. After development, it was washed with water and then dried to form a positive-type resist pattern (400 nm line, 800 nm pitch).

[0369] <Evaluation> The resist patterns formed using the above-mentioned positive-type radiation-sensitive composition for KrF exposure were evaluated for sensitivity, exposure margin, depth of field, pattern rectangularity, and number of development defects according to the following method. A scanning electron microscope (Hitachi High-Technologies Corporation's "CG-5000") was used to measure the length of the resist patterns. The results are shown in Table 3 below.

[0370] [Sensitivity] In forming a resist pattern using the above-mentioned positive-type radiation-sensitive composition for KrF exposure, the exposure amount used to form the 400 nm line and 800 nm pitch is defined as the optimal exposure amount, and this optimal exposure amount is defined as the sensitivity (mJ / cm²). ２ The sensitivity was set to 40 mJ / cm². ２ In the following cases, it is considered "good" and 40 mJ / cm². ２ If it exceeded this value, it was rated as "poor."

[0371] [EL Performance (Exposure Margin)] Within the exposure range including the optimal exposure amount mentioned above, the exposure amount is 1 mJ / cm². ２ Each resist pattern was formed by varying the exposure dose, and the line width of each pattern was measured using the scanning electron microscope described above. From the relationship between the obtained line width and exposure dose, the exposure dose E(440) at which the line width was 440 nm and the exposure dose E(360) at which the line width was 360 nm were determined, and the exposure margin (EL) was calculated using the formula: Exposure margin (EL) = (E(360) - E(440)) × 100 / (Optimal exposure dose). The larger the exposure margin value, the smaller the variation in the dimensions of the pattern obtained when the exposure dose is varied, and the higher the yield during device fabrication. EL performance was evaluated as "good" if it was 40% or higher, and "poor" if it was below 40%.

[0372] [Depth of Focus] In the resist pattern resolved at the optimal exposure amount determined in the sensitivity evaluation above, the dimensions were observed when the focus was changed in the depth direction. The margin in the depth direction where the pattern dimensions fall within 90% to 110% of the standard without bridging or residue was measured, and this measured value was defined as the depth of focus (nm). A larger depth of focus indicates a better result. A depth of focus of 200 nm or more is evaluated as "good," and a depth of focus of less than 200 nm is evaluated as "poor."

[0373] [Pattern Rectangularity] Line and space patterns with 400 nm lines and 800 nm pitch, formed by irradiating with the optimal exposure amount determined in the sensitivity evaluation above, were observed using a scanning electron microscope (Hitachi High-Technologies Corporation's "SU8220"), and the cross-sectional shape of the line and space patterns was evaluated. The rectangularity of the resist pattern was evaluated as follows: if the ratio of the length of the lower side to the length of the upper side in the cross-sectional shape of the line portion was 1 or more and 1.10 or less, it was evaluated as "A" (excellent); if it was greater than 1.10 and 1.20 or less, it was evaluated as "B" (good); and if it was greater than 1.20, it was evaluated as "C" (poor).

[0374] [Development Defect Count] A resist film was exposed at the optimal exposure level to form a line-and-space pattern with 400 nm lines and an 800 nm pitch, and this was used as a wafer for defect inspection. The number of defects on this wafer was measured using a defect inspection device (KLA-Tencor's "KLA2810"). Defects with a diameter of 50 μm or less were judged to be originating from the resist film, and their number was calculated. After development, the number of defects judged to be originating from the resist film was evaluated as "good" if it was 100 or less, and as "poor" if it exceeded 100.

[0375]

[0376] As is clear from the results in Table 3, when the radiation-sensitive composition of the example was used in KrF positive exposure, it exhibited good sensitivity, exposure margin, depth of field, pattern rectangularity, and development defect performance, whereas the comparative example exhibited inferior characteristics compared to the example. Therefore, when the radiation-sensitive composition of the example is used in KrF positive exposure, it is possible to form a resist pattern with optimal sensitivity and excellent roughness performance, pattern shape, defect performance, and yield.

[0377] [Preparation of Negative-Type Radiation-Sensitive Composition for KrF Exposure] [Example 34] A radiation-sensitive composition (J-34) was prepared by mixing 100 parts by mass of (B-5) as a polymer (B), 8.0 parts by mass of (A-1) as a radiation-sensitive acid generator (compound (A)), 3.0 parts by mass of (D-1) as an acid diffusion control agent (D), 7.0 parts by mass of (Q-1) as a crosslinking agent (Q), 1.0 part by mass of (W-1) as other additives (W), and 600 parts by mass of a mixed solvent of (E-1) / (E-4) as a solvent (E), and filtering the mixture through a membrane filter with a pore size of 0.2 μm.

[0378] [Examples 35-48 and Comparative Examples 4-6] Radiation-sensitive compositions (J-35) to (J-48) and (CJ-4) to (CJ-6) were prepared in the same manner as in Example 34, except that the components of the types and amounts shown in Table 4 below were used.

[0379]

[0380] <Formation of a resist pattern using a negative-type radiation-sensitive composition for KrF exposure> The prepared negative-type radiation-sensitive composition for KrF exposure was applied to a 12-inch silicon wafer treated with hexamethyldisilazane using a spin coater (CLEAN TRACK ACT12 from Tokyo Electron Limited), and pre-bake (PB) was performed at 130°C for 60 seconds. Subsequently, a resist film with an average thickness of 2.5 μm was formed by cooling at 23°C for 30 seconds. Next, this resist film was exposed using a KrF excimer laser scanner (PAS5500 / 850C wavelength 248 nm from ASML) under optical conditions of NA = 0.68 and σ = 0.60, through a mask pattern with 220 nm holes and a 450 nm pitch. After exposure, post-exposure bake (PEB) was performed at 130°C for 60 seconds. Subsequently, the resist film was alkaline-developed using a 2.38% by mass aqueous solution of TMAH as the alkaline developer. After development, it was washed with water and then dried to form a negative-type resist pattern (220 nm holes, 450 nm pitch).

[0381] <Evaluation> The sensitivity, depth of field, pattern circularity, and number of development defects of the resist patterns formed using the above-mentioned negative-type radiation-sensitive composition for KrF exposure were evaluated according to the following method. A scanning electron microscope (Hitachi High-Technologies Corporation's "CG-5000") was used to measure the length of the resist patterns. The results are shown in Table 5 below.

[0382] [Sensitivity] In forming a resist pattern using the above-mentioned negative-type radiation-sensitive composition for KrF exposure, the exposure amount used to form 220 nm holes and a 450 nm pitch is defined as the optimal exposure amount, and this optimal exposure amount is defined as the sensitivity (mJ / cm²). ２ The sensitivity was set to 30 mJ / cm². ２ The following conditions are considered "good" and 30 mJ / cm². ２ If it exceeded this value, it was rated as "poor."

[0383] [Depth of Focus] In the resist pattern resolved at the optimal exposure amount determined in the sensitivity evaluation above, the dimensions were observed when the focus was changed in the depth direction. The margin in the depth direction where the pattern dimensions fall within 90% to 110% of the standard without bridging or residue was measured, and this measured value was defined as the depth of focus (nm). A larger depth of focus indicates a better result. A depth of focus of 250 nm or more was evaluated as "good," and a depth of focus of less than 250 nm was evaluated as "poor."

[0384] [Pattern Circularity] The 220 nm holes and 450 nm pitch contact holes formed by irradiating with the optimal exposure amount determined in the sensitivity evaluation above were observed in plan view using the scanning electron microscope described above, and the vertical and horizontal sizes were measured. If the ratio of vertical size to horizontal size was 0.95 or more and 1.05 or less, it was evaluated as "A" (good); if it was 0.90 or more and less than 0.95, or greater than 1.05 and 1.10 or less, it was evaluated as "B" (poor); and if it was less than 0.90 or greater than 1.10, it was evaluated as "C" (very poor).

[0385] [Development Defect Count] A resist film was exposed at the optimal exposure level to form a contact hole pattern with 220 nm holes and a 450 nm pitch, and this was used as a wafer for defect inspection. The number of defects on this wafer was measured using a defect inspection device (KLA-Tencor's "KLA2810"). Defects with a diameter of 50 μm or less were judged to be originating from the resist film, and their number was calculated. After development, the number of defects judged to be originating from the resist film was evaluated as "good" if it was 200 or less, and as "poor" if it exceeded 200.

[0386]

[0387] As is clear from the results in Table 5, when the radiation-sensitive composition of the example was used in KrF negative exposure, it exhibited good sensitivity, depth of field, pattern circularity, and development defect performance, whereas the comparative example exhibited inferior characteristics compared to the example. Therefore, when the radiation-sensitive composition of the example is used in KrF negative exposure, it is possible to form a resist pattern with optimal sensitivity and excellent roughness performance, pattern shape, and defect performance.

[0388] [Preparation of positive-type radiation-sensitive composition for extreme ultraviolet (EUV) exposure] [Example 49] A radiation-sensitive composition (J-49) was prepared by mixing 100 parts by mass of (B-8) as polymer (B), 25.0 parts by mass of (A-4) and 10.0 parts by mass of (a-3) as radiation-sensitive acid generators (compound (A)), 40.0 parts by mass of (D-5) as acid diffusion control agent (D), and 6,800 parts by mass of a mixed solvent of (E-1) / (E-2) as solvent (E), and filtering the mixture through a membrane filter with a pore size of 0.2 μm.

[0389] <Formation of a resist pattern using a positive-type radiation-sensitive composition for EUV exposure> An anti-reflective underlayer film (ARC66 from Brewer Sciences) was applied to a 12-inch silicon wafer using a spin coater (CLEAN TRACK ACT12 from Tokyo Electron Limited), and then heated at 205°C for 60 seconds to form an anti-reflective underlayer film with an average thickness of 105 nm. The prepared positive-type radiation-sensitive composition for EUV exposure was applied to this anti-reflective underlayer film using the spin coater, and PB (plate blot) was performed at 130°C for 60 seconds. Subsequently, a resist film with an average thickness of 80 nm was formed by cooling at 23°C for 30 seconds. Next, the resist film was exposed using an EUV lithography system (ASML's "NXE3300") with NA = 0.33, illumination conditions: Conventional s = 0.89, and mask: imecDEFECT32FFR02. After exposure, PEB was performed at 120°C for 60 seconds. Subsequently, the resist film was alkaline developed using a 2.38 mass% TMAH aqueous solution as the alkaline developer, washed with water after development, and then dried to form a positive-type resist pattern (40 nm contact hole pattern).

[0390] <Evaluation> The sensitivity and CDU of the resist patterns formed using the above-mentioned positive-type radiation-sensitive composition for EUV exposure were evaluated according to the following method. A scanning electron microscope (Hitachi High-Technologies Corporation's "CG-5000") was used to measure the length of the resist patterns.

[0391] [Sensitivity] In forming a resist pattern using the above-mentioned positive-type radiation-sensitive composition for EUV exposure, the exposure amount used to form a 40 nm contact hole pattern is defined as the optimal exposure amount, and this optimal exposure amount is defined as the sensitivity (mJ / cm²). ２ The sensitivity was set to 50 mJ / cm². ２ The following conditions are considered "good" and 50 mJ / cm². ２ If it exceeded this value, it was rated as "poor."

[0392] [CDU] The mask size was adjusted to form a 40 nm contact hole pattern by irradiating with the optimal exposure amount determined in the sensitivity evaluation above, and a resist pattern was formed. The formed resist pattern was observed from the top of the pattern using the scanning electron microscope described above. The hole diameter was measured at 16 points in the range of 500 nm and the average value was calculated. This average value was measured at a total of 500 points at arbitrary points, and the 1 sigma value was calculated from the distribution of the measured values, and this was defined as CDU (nm). A smaller CDU value indicates less variation in hole diameter over long periods and is therefore better. A CDU of 3.0 nm or less was evaluated as "good," and a value greater than 3.0 nm was evaluated as "poor."

[0393] The radiation-sensitive composition of Example 49 exhibited good sensitivity and CDU even when used in EUV positive exposure.

[0394] [Preparation of negative-type radiation-sensitive composition for i-ray exposure] [Example 50] A radiation-sensitive composition (J-50) was prepared by mixing 50.0 parts by mass of (B-i-1) and (B-i-2) as polymers (B), 6.0 parts by mass of (A-3) as a radiation-sensitive acid generator (compound (A)), 1.0 part by mass of (D-2) as an acid diffusion control agent (D), 10.0 parts by mass of (Q-1) as a crosslinking agent (Q), 40.0 parts by mass of (W-3) as other additives (W), and 300 parts by mass of a mixed solvent of (E-3) / (E-4) as a solvent (E), and filtering the mixture through a membrane filter with a pore size of 0.5 μm.

[0395] <Formation of a resist pattern using a negative-type radiation-sensitive composition for i-line lithography> The prepared negative-type radiation-sensitive composition for i-line lithography was applied to an 8-inch silicon wafer treated with hexamethyldisilazane using a spin coater (CLEAN TRACK ACT8 from Tokyo Electron Limited), and pre-bake (PB) was performed at 110°C for 60 seconds. Subsequently, a resist film with an average thickness of 4.0 μm was formed by cooling at 23°C for 30 seconds. Next, this resist film was exposed using an i-line lithography machine (Nikon 2205i14E2, wavelength 365 nm) under optical conditions of NA = 0.50 and σ = 0.60, through a mask pattern with 2.0 μm lines and 5.0 μm spaces. After exposure, post-exposure bake (PEB) was performed at 106°C for 60 seconds. Subsequently, the resist film was alkaline-developed using a 2.38% by mass aqueous solution of TMAH as the alkaline developer. After development, it was washed with water and then dried to form a negative-type resist pattern (2.0 μm lines, 5.0 μm spaces).

[0396] <Evaluation> The sensitivity, pattern rectangularity, exposure margin, and depth of field of the resist patterns formed using the above i-line exposure negative radiation-sensitive composition were evaluated according to the following method. A scanning electron microscope (Hitachi High-Technologies Corporation's "CS-4800") was used.

[0397] [Sensitivity] In forming a resist pattern using the above i-line exposure negative radiation-sensitive composition, the exposure amount used to form a 2.0 μm line and a 5.0 μm space was defined as the optimal exposure amount, and this optimal exposure amount was defined as the sensitivity (msec). Sensitivity was evaluated as "good" if it was 200 msec or less, and as "poor" if it exceeded 200 msec.

[0398] [Pattern Rectangularity] The patterns of 2.0 μm lines and 5.0 μm spaces formed by irradiating with the optimal exposure amount determined in the sensitivity evaluation above were observed using a scanning electron microscope (Hitachi High-Technologies Corporation's "SU8220"), and the cross-sectional shape of the line patterns was evaluated. The rectangularity of the resist pattern was evaluated as follows: if the difference between the length of the lower side and the length of the upper side in the cross-sectional shape of the line portion was 100 nm or less, it was evaluated as "A" (excellent); if it was between 100 nm and 200 nm, it was evaluated as "B" (good); and if it was greater than 200 nm, it was evaluated as "C" (poor).

[0399] [EL Performance (Exposure Margin)] Within the exposure range including the optimal exposure amount described above, resist patterns were formed by changing the exposure amount every 5 msec, and the CD of each pattern was measured using the scanning electron microscope described above. From the relationship between the obtained dimensions and exposure amount, the exposure amount E(1.8) at which the line dimension is 1.8 μm and the exposure amount E(2.2) at which the line width is 2.2 μm were determined, and the exposure margin (EL) was calculated using the formula: Exposure margin (EL) = (E(1.8) - E(2.2)) × 100 / (Optimal exposure amount). The larger the exposure margin value, the smaller the variation in the dimensions of the pattern obtained when the exposure amount is varied, and the higher the yield during device fabrication. EL performance was evaluated as "good" if it was 40% or more, and as "poor" if it was below 40%.

[0400] [Depth of Focus] In the resist pattern resolved at the optimal exposure amount determined in the sensitivity evaluation above, the dimensions were observed when the focus was changed in the depth direction. The margin in the depth direction where the pattern dimensions fall within 90% to 110% of the standard without bridging or residue was measured, and this measured value was defined as the depth of focus (nm). A larger depth of focus indicates a better result. A depth of focus of 2.0 μm or more is evaluated as "good," and a depth of focus of less than 2.0 μm is evaluated as "poor."

[0401] The radiation-sensitive composition of Example 50 exhibited good sensitivity, exposure margin, depth of field, and pattern rectangularity even when used in i-line negative exposure.

[0402] [Preparation of positive-type radiation-sensitive composition for ArF immersion exposure] [Example 51] 100 parts by mass of (B-9) as polymer (B), 8.0 parts by mass of (A-1) and 2.0 parts by mass of (a-3) as radiation-sensitive acid generators (compound (A)), 8.0 parts by mass of (D-5) as acid diffusion control agent (D), 3.0 parts by mass of (F-1) as high-fluorine-content polymer (F), and 3,400 parts by mass of a mixed solvent of (E-1) / (E-2) / (E-5) as solvent (E) were mixed and filtered through a membrane filter with a pore size of 0.2 μm to prepare a radiation-sensitive composition (J-51).

[0403] <Formation of a resist pattern using a positive-type radiation-sensitive composition for ArF immersion lithography> An anti-reflective underlayer film formation composition (ARC66 from Brewer Sciences) was applied to a 12-inch silicon wafer using a spin coater (CLEAN TRACK ACT12 from Tokyo Electron Limited), and then heated at 205°C for 60 seconds to form an anti-reflective underlayer film with an average thickness of 100 nm. The positive-type radiation-sensitive composition for ArF lithography prepared above was applied to this anti-reflective underlayer film using the spin coater, and pre-bake (PB) was performed at 100°C for 60 seconds. Subsequently, a resist film with an average thickness of 90 nm was formed by cooling at 23°C for 30 seconds. Next, the resist film was exposed to a 60 nm line-and-space mask pattern using an ArF excimer laser immersion lithography system (ASML's "TWINSCAN XT-1900i") under optical conditions of NA = 1.35 and Dipole (σ = 0.9 / 0.7). After exposure, post-exposure baking (PEB) was performed at 100°C for 60 seconds. Subsequently, the resist film was alkaline developed using a 2.38 mass% TMAH aqueous solution as the alkaline developer, washed with water after development, and then dried to form a positive-type resist pattern (60 nm line-and-space pattern).

[0404] <Evaluation> The sensitivity and LWR of the resist patterns formed using the above ArF immersion exposure positive-type radiation-sensitive composition were evaluated according to the following method. A scanning electron microscope (Hitachi High-Technologies Corporation's "CG-5000") was used to measure the length of the resist patterns.

[0405] [Sensitivity] In forming a resist pattern using the above ArF immersion lithography positive-type radiation-sensitive composition, the exposure amount used to form a 60 nm line-and-space pattern is defined as the optimal exposure amount, and this optimal exposure amount is defined as the sensitivity (mJ / cm²). ２ The sensitivity was set to 30 mJ / cm². ２ The following conditions are considered "good" and 30 mJ / cm². ２ If it exceeded this value, it was rated as "poor."

[0406] [LWR] A 60 nm line-and-space resist pattern was formed by irradiating with the optimal exposure amount determined in the sensitivity evaluation above. The formed resist pattern was observed from the top of the pattern using the scanning electron microscope described above. The variation in line width was measured at a total of 500 points, and the 3-sigma value was determined from the distribution of these measurements. This 3-sigma value was defined as LWR (nm). A smaller LWR value indicates less line roughness and better quality. An LWR of 4.0 nm or less was evaluated as "good," and an LWR greater than 4.0 nm was evaluated as "poor."

[0407] The radiation-sensitive composition of Example 51 exhibited good sensitivity and LWR even when used in ArF positive immersion lithography.

[0408] The radiation-sensitive composition and resist pattern formation method described above allow for the formation of resist patterns with good sensitivity to exposure light and excellent roughness performance, yield performance, pattern shape, and defect performance. Therefore, these can be suitably used in semiconductor device processing processes and the like, where further miniaturization is expected in the future.

Claims

A nonionic radiation-sensitive acid generator having a substructure represented by the following formula (a-1) and a sulfonyl group, Polymers and Solvent and A radiation-sensitive composition containing the following: (In formula (a-1), R Ｘ This is a hydrogen atom or a monovalent organic group having one or more carbon atoms. L is a single bond or a divalent linking group. R ｆ１ and R ｆ２ are each independently a hydrogen atom, -CN, -NO ２ , -F, -CF ２ R ｔ１ , -SO ２ R ｔ２ , -COR ｔ３ , or -CF ２ R ｔ１ , -SO ２ R ｔ２ , -COR ｔ３ or a monovalent organic group (a) having 1 to 20 carbon atoms other than -CF ３ . R ｔ１ is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. R ｔ２ and R ｔ３ are each independently a monovalent organic group having 1 to 20 carbon atoms. When a plurality of R ｆ１ and R ｆ２ exist, the plurality of R ｆ１ and R ｆ２ may each be the same or different from each other. 　 n is an integer between 1 and 5. * represents the bond between the sulfonyl group and the sulfur atom. however, R ｆ１ and R ｆ２ At least one of them is -CN, -NO ２ -F, -CF ２ R ｔ１ , -SO ２ R ｔ２ , or -COR ｔ３ and one or more R ｆ１ If R is -F, then R is -F. ｆ１ R bonded to the carbon atom to which it is attached. ｆ２ is a group other than -F, R ｆ１ and R ｆ２ At least one of them is -CN or -SO ２ R ｔ２ If R Ｘ is a hydrogen atom, or a monovalent organic group having one or more carbon atoms, R ｆ１ and R ｆ２ However, -CN or -SO ２ R ｔ２ For groups other than R Ｘ (This refers to a monovalent organic group having one or more carbon atoms.) 　 The radiation-sensitive composition according to claim 1, wherein the above-mentioned radiation-sensitive acid generator is one or more compounds selected from the group consisting of a compound represented by the following formula (1), a compound represented by the following formula (2), and a compound represented by the following formula (3). (In formulas (1) to (3), R １ and R ２ Each of these is independently either a cyano group, a nitro group, a monovalent organic group having 1 to 20 carbon atoms, or R １ and R ２ These atoms are combined with each other, forming a cyclic structure with the atoms they bond to. R ３ It is a monovalent organic group having 1 to 20 carbon atoms. R ａ This is a substructure represented by the above formula (a-1). 　 In the above formulas (1) to (3), the carbon atom at the α position of the sulfur atom is -CN, -F, -CF ２ H, and -SO ２ R ｔ２ The radiation-sensitive composition according to claim 2, having at least one group selected from the group consisting of the following. 　 The above L is a single bond, *-COO-, *-OCO-, or -CO- (* is R Ｘ The radiation-sensitive composition according to claim 1, which is a side bonding. 　 The radiation-sensitive composition according to claim 2, wherein the compound represented by formula (1) above is the compound represented by formula (1-1) below. (In formula (1-1), W is a nitrogen-containing alicyclic heterocycle. R １１ is a cyano group, nitro group, hydroxyl group, carboxyl group, or a monovalent organic group having 1 to 5 carbon atoms, or two R groups. １１ These atoms are combined with each other to form a cyclic structure with 3 to 20 carbon atoms, along with the atoms to which they bond. １１ If multiple R １１ They are either the same or different. 　 n1 is an integer between 0 and 5. R ａ This is equivalent to equation (1). 　 The radiation-sensitive composition according to any one of claims 1 to 5, wherein the content of the above-mentioned radiation-sensitive acid generator is 0.1 parts by mass or more and 60 parts by mass or less per 100 parts by mass of the above-mentioned polymer. 　 The above polymer comprises a structural unit having a phenolic hydroxyl group, the radiation-sensitive composition according to any one of claims 1 to 5. 　 The above polymer comprises a structural unit having an acid-dissociable group, the radiation-sensitive composition according to any one of claims 1 to 5. 　 A radiation-sensitive composition according to any one of claims 1 to 5, further comprising an acid diffusion control agent. 　 A step of forming a resist film by directly or indirectly applying the radiation-sensitive composition according to any one of claims 1 to 5 to a substrate, The process of exposing the above-mentioned resist film, The process involves developing the exposed resist film with a developer solution. A pattern formation method including the following. 　 The pattern formation method according to claim 10, wherein the above exposure is performed using an ArF excimer laser, a KrF excimer laser, or an i-line. 　 A compound represented by any of the following formulas: (1), (2'), and (3). (In equations (1), (2'), and (3), R １ and R ２ Each of these is independently either a cyano group, a nitro group, a monovalent organic group having 1 to 20 carbon atoms, or R １ and R ２ These atoms are combined with each other, forming a cyclic structure with the atoms they bond to. R ３ It is a monovalent organic group having 1 to 20 carbon atoms. R ａ This is a group represented by the following formula (a-1). (In formula (a-1), R Ｘ This is a hydrogen atom or a monovalent organic group having one or more carbon atoms. L is a single bond or a divalent linking group. R ｆ１ and R ｆ２ These are, independently, a hydrogen atom, -CN, and -NO. ２ -F, -CF ２ R ｔ１ , -SO ２ R ｔ２ ,-COR ｔ３ , or -CF ２ R ｔ１ , -SO ２ R ｔ２ ,-COR ｔ３ Or -CF ３ (a) is a monovalent organic group with 1 to 20 carbon atoms other than R. ｔ１ R is a hydrogen atom or a monovalent organic group having 1 to 20 carbon atoms. ｔ２ and R ｔ３ Each of these is independently a monovalent organic group having 1 to 20 carbon atoms. ｆ１ and R ｆ２ If multiple R ｆ１ and R ｆ２ They are either the same or different. 　 n is an integer between 1 and 5. * represents a bond with a sulfur atom in formula (1) or formula (3). however, R ｆ１ and R ｆ２ at least one of which is -CN, -NO ２ , -F, -CF ２ R ｔ１ , -SO ２ R ｔ２ , or -COR ｔ３ , and when one or more R ｆ１ is -F, the R ｆ１ bonded to the carbon atom to which the -F R ｆ２ is bonded is a group other than -F, R ｆ１ and R ｆ２ At least one of them is -CN or -SO ２ R ｔ２ If R Ｘ is a hydrogen atom, or a monovalent organic group having one or more carbon atoms, R ｆ１ and R ｆ２ However, -CN or -SO ２ R ｔ２ For groups other than R Ｘ (This refers to a monovalent organic group having one or more carbon atoms.) R ａ１ This is a group represented by the following formula (a-11). (In formula (a-11), R Ｘ１ This is a monovalent organic group having one or more carbon atoms. L, R ｆ１ , R ｆ２ And n are equivalent to the above formula (a-1). however, R ｆ１ and R ｆ２ At least one of them is -CN, -NO ２ -F, -CF ２ R ｔ１ , -SO ２ R ｔ２ , or -COR ｔ３ and one or more R ｆ１ If R is -F, then R is -F. ｆ１ R bonded to the carbon atom to which it is attached. ｆ２ This is a group other than -F.

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