CN118812766A - Resist material, resist composition, pattern forming method, and monomer - Google Patents

Abstract

The invention relates to a resist material, a resist composition, a pattern forming method, and a monomer. The present invention addresses the problem of providing a resist material which has high sensitivity and high resolution, and which has small edge roughness and dimensional variation and good pattern shape after exposure, as well as a resist composition containing the resist material, a pattern forming method, and a monomer which is a raw material of the resist material. The solution to this problem is a resist material characterized in that: a repeating unit a comprising a sulfonium salt or iodonium salt of a substituted or unsubstituted iodinated 1-valent aromatic carboxylic acid bonded by an ester bond spaced from the polymer main chain.

Description

Resist material, resist composition, pattern forming method, and monomer

Technical Field

The present invention relates to a resist material, a resist composition, a pattern forming method, and a monomer.

Background Art

With the high integration and high speed of LSI, the miniaturization of pattern rules is also progressing rapidly. The reason is that with the popularization of 5G high-speed communication and artificial intelligence (AI), high-performance devices are required to handle them. As for the most advanced miniaturization technology, mass production of 5nm node devices using extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm is already underway. In addition, discussions are underway to use EUV lithography in the next-generation 3nm node and the next-generation 2nm node devices.

As the miniaturization progresses, the blurring of the image caused by the diffusion of acid will become a problem. In order to ensure the resolution of fine patterns with a size of less than 45nm, it has been proposed that it is not only important to improve the dissolution contrast as previously advocated, but also to control the diffusion of acid (Non-Patent Document 1). However, since chemically amplified resist materials use the diffusion of acid to improve sensitivity and contrast, if the post-exposure baking (PEB) temperature is lowered or the time is shortened to suppress the diffusion of acid to the limit, the sensitivity and contrast will also be significantly reduced.

The triangle trade-off relationship between sensitivity, resolution, and edge roughness is shown. In order to improve resolution, acid diffusion must be suppressed, but if the acid diffusion distance is shortened, the sensitivity will decrease.

It is effective to add an acid generator that generates a bulky acid to inhibit acid diffusion. Therefore, it has been proposed that a repeating unit from an onium salt having a polymerizable unsaturated bond be contained in the polymer. In this case, the polymer can also function as an acid generator (polymer-bonded acid generator). Patent Document 1 has proposed sulfonium salts and iodonium salts having a polymerizable unsaturated bond that generate specific sulfonic acids. Patent Document 2 has proposed sulfonium salts in which sulfonic acid is directly bonded to the main chain.

In order to suppress acid diffusion, resist materials using a polymer-bound quencher of a sulfonium salt having a polymerizable group with a pKa of -0.8 or higher as a base polymer have been proposed (Patent Documents 3 to 5). Patent Document 3 lists carboxylic acid, sulfonamide, phenol, hexafluoroalcohol, and the like as weak acids.

Prior art literature

Patent Literature

[Patent Document 1] Japanese Patent Application Publication No. 2006-045311

[Patent Document 2] Japanese Patent Application Publication No. 2006-178317

[Patent Document 3] International Publication No. 2019/167737

[Patent Document 4] International Publication No. 2022/264845

[Patent Document 5] Japanese Patent Application Publication No. 2022-115072

Non-patent literature

[Non-patent document 1] SPIE Vol.6520 65203L-1 (2007)

Summary of the invention

[Problems to be solved by the invention]

The present invention is made in view of the above situation, and its purpose is to provide a resist material with higher sensitivity and higher resolution than the known positive resist materials, with small edge roughness and dimensional variation, and good pattern shape after exposure, as well as to provide a resist composition containing the above-mentioned resist material, a pattern forming method, and a monomer which is the raw material of the above-mentioned resist material.

[Methods to solve the problem]

In order to solve the above problems, the present invention provides a resist material comprising a repeating unit a containing a sulfonium salt or iodonium salt of a substituted or unsubstituted iodinated monovalent aromatic carboxylic acid bonded to a polymer main chain via an ester bond.

Such a resist material has high sensitivity and high resolution exceeding those of known positive resist materials, has small edge roughness and dimensional variation, and has a good pattern shape after exposure.

In the present invention, the repeating unit a preferably includes a repeating unit represented by the following general formula (a)-1 or (a)-2.

[Chemistry 1]

In the formula, ^RA is a hydrogen atom or a methyl group. ^X1' is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing an ester bond or an ether bond, and may also have one or more selected from a halogen atom, a hydroxyl group, an alkoxy group, an acyloxy group, a nitro group, and a cyano group. ^X2 is a single bond or a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms without a fluorine atom, and may also have one or more selected from an ether group and an ester group. Y is a group selected from an ester group and a sulfonate group. ^R1 is independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer of 1 to 4, and n is an integer of 0 to 3. R ² to R ⁶ are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a hetero atom. In addition, any two of R ² , R ³ and R ⁴ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

The repeating unit a preferably has such a structure.

In this case, in the aforementioned general formulae (a)-1 and (a)-2, the aforementioned ^X2 is preferably a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom.

The repeating unit a is more preferably of such a structure.

Furthermore, in the present invention, it is preferred to further contain a repeating unit b in which the hydrogen atom of either or both of a carboxyl group and a phenolic hydroxyl group is substituted with an acid-labile group.

Such a resist material can have higher sensitivity and less dimensional variation.

In this case, the complex unit b is preferably at least one selected from the repeating units represented by the following general formulae (b1) and (b2).

[Chemistry 2]

In the formula, ^RA is independently a hydrogen atom or a methyl group. ^Y1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and having an ester bond, an ether bond, or a lactone ring. ^Y2 is a single bond, an ester bond, or an amide bond. ^R11 and ^R12 are acid-labile groups. ^R13 is a fluorine atom, a trifluoromethyl group, a cyano group, or an alkyl group having 1 to 6 carbon atoms. ^R14 is a single bond or a linear or branched alkanediyl group having 1 to 6 carbon atoms, and a portion of the carbon atoms thereof may be substituted by an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4.

The repeating unit b preferably has such a structure.

Furthermore, in the present invention, the resist material preferably further contains a repeating unit c having an adhesive group selected from a hydroxyl group, a carboxyl group, a lactone ring, a carbonate group, a thiocarbonate group, a carbonyl group, a cyclic acetal group, an ether bond, an ester bond, a sulfonate bond, a cyano group, an amide group, -O-C(=O)-S-, and -O-C(=O)-NH-.

Such a resist material can have excellent adhesion to the substrate.

In the present invention, the resist material preferably further contains at least one repeating unit d selected from the repeating units represented by the following general formulae (d1) to (d3).

[Chemistry 3]

In the formula, ^RA is independently a hydrogen atom or a methyl group. ^Z1 is a single bond, a phenylene group, ^-OZ11- , -C(=O) ^-OZ11- or -C(=O)-NH- ^Z11- , ^Z11 is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms or a phenylene group, and may contain one or more selected from a carbonyl group, an ester bond, an ether bond, and a hydroxyl group. ^{Z2A is a single bond or an ester bond. Z2B is} a single bond or a divalent group having 1 to 12 carbon atoms, and may contain one or more selected from an ester bond, an ether bond, a lactone ring, a bromine atom, and an iodine atom. ^Z3 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, ^-OZ31- , -C(=O) ^-OZ31- or -C(=O)-NH- ^Z31- , ^Z31 is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms or a phenylene group, and may contain one or more selected from a carbonyl group, an ester bond, an ether bond, a halogen atom, and a hydroxyl group. ^Rf1 to ^Rf4 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of them is a fluorine atom. ^R21 to ^R28 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. In addition, any two of ^R23 , ^R24 and ^R25 or any two of ^R26 , ^R27 and ^R28 may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. ^M- is a non-nucleophilic counter ion.

Such a resist material can reduce acid diffusion and prevent a reduction in resolution due to blurring caused by acid diffusion.

In this case, the aforementioned Z ^2B preferably contains at least one iodine atom.

The repeating unit d is more preferably such a structure.

Furthermore, in the present invention, the molecular weight of the resist material is preferably in the range of 1,000 to 100,000.

Such a resist material has excellent heat resistance, maintains alkali solubility, and does not cause a tailing phenomenon after pattern formation.

Furthermore, the present invention provides a resist composition, characterized in that it contains the resist material described above.

Such a resist composition has high sensitivity and high resolution exceeding those of known positive resist materials, has small edge roughness and dimensional variation, and has a good pattern shape after exposure.

In this case, it is preferred to further contain one or more selected from the group consisting of an acid generator, an organic solvent, a quencher, and a surfactant.

Such substances may be added to the resist composition of the present invention.

Furthermore, the present invention provides a pattern forming method, comprising the following steps:

Using the resist composition described above to form a resist film on a substrate,

exposing the resist film to high energy radiation, and

The exposed resist film is developed using a developer.

According to such a pattern forming method, a pattern having a good pattern shape can be formed.

In this case, i-rays, KrF excimer lasers, ArF excimer lasers, electron beams, or extreme ultraviolet rays having a wavelength of 3 to 15 nm are preferably used as the high-energy rays.

The pattern forming method of the present invention can use such high-energy rays.

The present invention also provides a monomer represented by the following general formula (a)-1M or (a)-2M.

[Chemistry 4]

In the formula, ^RA is a hydrogen atom or a methyl group. ^X1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing an ester bond or an ether bond, and may also contain a halogen atom. ^X2 is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms without a fluorine atom, and may also contain one or more selected from an ether group and an ester group. ^R1 is independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer of 1 to 4, and n is an integer of 0 to 3. ^R2 to ^R6 are independently a monovalent hydrocarbon group having 1 to 25 carbon atoms, which may also contain a heteroatom. Furthermore, any two of R ² , R ³ and R ⁴ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

The present invention also provides a monomer represented by the following general formula (a)-1'M or (a)-2'M.

[Chemistry 5]

In the formula, ^RA is a hydrogen atom or a methyl group. ^X1' is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing an ester bond or an ether bond, and may also have one or more selected from a halogen atom, a hydroxyl group, an alkoxy group, an acyloxy group, a nitro group, and a cyano group. ^X2 is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms without a fluorine atom, and may also have one or more selected from an ether group and an ester group. Y is a group selected from an ester group and a sulfonate group. ^R1 is independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer of 1 to 4, and n is an integer of 0 to 3. R ² to R ⁶ are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a hetero atom. In addition, any two of R ² , R ³ and R ⁴ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

Such a monomer can be used as a raw material of a resist material having high sensitivity and high resolution exceeding known positive resist materials, small edge roughness and dimensional variation, and a good pattern shape after exposure.

[Effects of the Invention]

Resist material of the present invention can improve the decomposition efficiency of acid generator, so the effect of suppressing the diffusion of acid is high, and is highly sensitive and has high resolution, and the pattern shape, edge roughness and size variation after exposure are small, which is good. Therefore, owing to having these excellent characteristics, it is extremely practical, and is particularly useful as the fine pattern forming material of the photomask used for ultra-large integrated circuit manufacturing or EB description, and the pattern forming material used for EB or EUV exposure. Positive resist material of the present invention can not only be applied to photolithography when semiconductor circuit is formed, but also can be applied to the formation of mask circuit pattern, micromachine, and thin film magnetic head circuit formation.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a diagram showing the ¹ H-NMR (500 MHz, DMSO-d ₆ ) spectrum of Compound 2 synthesized in Synthesis Example 1-1.

[ Fig. 2 ] is a diagram showing the ¹ H-NMR (500 MHz, DMSO-d ₆ ) spectrum of Compound 3 synthesized in Synthesis Example 1-1.

[ Fig. 3 ] is a diagram showing the ¹ H-NMR (500 MHz, DMSO-d ₆ ) spectrum of Compound 4 synthesized in Synthesis Example 1-1.

Fig. 4 is a diagram showing the ¹ H-NMR (500 MHz, DMSO-d ₆ ) spectrum of Monomer 1 synthesized in Synthesis Example 1-1.

DETAILED DESCRIPTION

As described above, it is required to develop a resist material which has higher sensitivity and higher resolution than the known positive resist materials, has small edge roughness and dimensional variation, and has a good pattern shape after exposure, as well as a resist composition containing the aforementioned resist material, a pattern forming method, and a monomer which is a raw material of the aforementioned resist material.

The inventors of the present application have repeatedly conducted in-depth studies in order to obtain a positive resist material with high resolution and small edge roughness (LWR) and dimension variation (CDU) required in recent years, and have obtained the following findings: it is necessary to shorten the acid diffusion distance to the limit and make the acid diffusion distance uniform at the molecular level. By using a polymer containing a specific repeating unit as a base polymer, and the repeating unit having a substituted or unsubstituted iodinated monovalent aromatic carboxylic acid sulfonium salt or iodonium salt bonded to the polymer main chain via an ester bond, the acid diffusion becomes very small. In addition, since the alkali solubility property of the iodinated monovalent aromatic carboxylic acid generated by exposure is low swelling, it is effective to make a base polymer of a chemically amplified resist material with good LWR and CDU by virtue of the two effects of uniformizing the acid diffusion distance and the low swelling effect.

In addition, the following insights were obtained, leading to the completion of the present invention: in order to improve the dissolution contrast, a repeating unit in which the hydrogen atoms of a carboxyl group or a phenolic hydroxyl group are replaced by an acid-labile group is introduced, thereby obtaining a resist material with high sensitivity and a greatly improved contrast of the alkali dissolution rate before and after exposure, and a high sensitivity and a high effect of inhibiting acid diffusion, high resolution, and small and good variation in pattern shape, edge roughness, and size after exposure, and is particularly suitable as a resist material for use in ultra-large integrated circuit manufacturing or as a fine pattern forming material for a photomask.

That is, the present invention is a resist material comprising a repeating unit a comprising a sulfonium salt or iodonium salt of a substituted or unsubstituted iodinated monovalent aromatic carboxylic acid bonded to a polymer main chain via an ester bond.

Furthermore, the present invention is a monomer represented by the following general formula (a)-1M or (a)-2M.

[Chemistry 6]

In the formula, ^RA is a hydrogen atom or a methyl group. ^X1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing an ester bond or an ether bond, and may also contain a halogen atom. ^X2 is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms without a fluorine atom, and may also contain one or more selected from an ether group and an ester group. ^R1 is independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer of 1 to 4, and n is an integer of 0 to 3. ^R2 to ^R6 are independently a monovalent hydrocarbon group having 1 to 25 carbon atoms, which may also contain a heteroatom. Furthermore, any two of R ² , R ³ and R ⁴ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

Furthermore, the present invention is a monomer represented by the following general formula (a)-1'M or (a)-2'M.

[Chemistry 7]

In the formula, ^RA is a hydrogen atom or a methyl group. ^X1' is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing an ester bond or an ether bond, and may also have one or more selected from a halogen atom, a hydroxyl group, an alkoxy group, an acyloxy group, a nitro group, and a cyano group. ^X2 is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms without a fluorine atom, and may also have one or more selected from an ether group and an ester group. Y is a group selected from an ester group and a sulfonate group. ^R1 is independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer of 1 to 4, and n is an integer of 0 to 3. R ² to R ⁶ are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a hetero atom. In addition, any two of R ² , R ³ and R ⁴ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[monomer]

The present invention is a monomer represented by the following general formula (a)-1M or (a)-2M.

[Chemistry 8]

In the formula, ^RA is a hydrogen atom or a methyl group. ^X1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing an ester bond or an ether bond, and may also contain a halogen atom. ^X2 is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms without a fluorine atom, and may also contain one or more selected from an ether group and an ester group. ^R1 is independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer of 1 to 4, and n is an integer of 0 to 3. ^R2 to ^R6 are independently a monovalent hydrocarbon group having 1 to 25 carbon atoms, which may also contain a heteroatom. Furthermore, any two of R ² , R ³ and R ⁴ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

In the formula, ^RA is a hydrogen atom or a methyl group, preferably a methyl group. ^X1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and containing an ester bond or an ether bond, and may also contain a halogen atom, preferably a single bond or one containing a phenylene group. ^X2 is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom, and preferably one containing an ether group. ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms and not containing a fluorine atom, and may also contain one or more selected from an ether group and an ester group, and preferably a single bond, a methylene group, an ethylene group, or a propylene group. ^R1 is independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine, and preferably a fluorine atom. m is an integer of 1 to 4, n is an integer of 0 to 3, preferably m = 1 to 2, n = 0 to 1. ^{R 2} to R ⁶ are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a heteroatom, preferably an aromatic hydrocarbon group, more preferably a phenyl group, a naphthyl group, a biphenyl group, a phenyl sulfide group, a phenyl ether group, or a benzophenone group.

Furthermore, the present invention is a monomer represented by the following general formula (a)-1'M or (a)-2'M.

[Chemistry 9]

In the formula, ^RA is a hydrogen atom or a methyl group. ^X1' is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing an ester bond or an ether bond, and may also have one or more selected from a halogen atom, a hydroxyl group, an alkoxy group, an acyloxy group, a nitro group, and a cyano group. ^X2 is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms without a fluorine atom, and may also have one or more selected from an ether group and an ester group. Y is a group selected from an ester group and a sulfonate group. ^R1 is independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer of 1 to 4, and n is an integer of 0 to 3. R ² to R ⁶ are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a hetero atom. In addition, any two of R ² , R ³ and R ⁴ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

In the formula, ^RA is a hydrogen atom or a methyl group, preferably a methyl group. ^X1' is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and containing an ester bond or an ether bond, and may also have one or more selected from a halogen atom, a hydroxyl group, an alkoxy group, an acyloxy group, a nitro group, and a cyano group, preferably a single bond or one containing a phenylene group. ^X2 is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom, and preferably one containing an ether group. ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms and not containing a fluorine atom, and may also have one or more selected from an ether group and an ester group, and preferably a single bond, a methylene group, an ethylene group, or a propylene group. Y is a group selected from an ester group and a sulfonate group. ^R1 is independently a linear or branched alkyl group, alkoxy group, acyloxy group, or halogen atom other than iodine, preferably a fluorine atom. m is an integer of 1 to 4, n is an integer of 0 to 3, preferably m=1 to 2, n=0 to 1. ^R2 to ^R6 are independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a heteroatom, preferably an aromatic hydrocarbon group, more preferably a phenyl group, a naphthyl group, a biphenyl group, a phenyl sulfide group, a phenyl ether group, or a benzophenone group.

[Resist material]

The resist material of the present invention contains a repeating unit a containing a sulfonium salt or iodonium salt of a substituted or unsubstituted iodinated monovalent aromatic carboxylic acid bonded to the polymer main chain via an ester bond. The monovalent aromatic carboxylic acid is preferably benzoic acid. The repeating unit a preferably contains a repeating unit represented by the following general formula (a)-1 or (a)-2.

[Chemistry 10]

In the formula, ^RA is a hydrogen atom or a methyl group. ^X1' is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing an ester bond or an ether bond, and may also have one or more selected from a halogen atom, a hydroxyl group, an alkoxy group, an acyloxy group, a nitro group, and a cyano group. ^X2 is a single bond or a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms without a fluorine atom, and may also have one or more selected from an ether group and an ester group. Y is a group selected from an ester group and a sulfonate group. ^R1 is independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer of 1 to 4, and n is an integer of 0 to 3. R ² to R ⁶ are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a hetero atom. In addition, any two of R ² , R ³ and R ⁴ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

In the above-mentioned general formulas (a)-1 and (a)-2, the above-mentioned ^X2 is preferably a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may contain one or more selected from ester groups, ether groups, amide groups, lactone rings, sultone rings, and halogen atoms. By having a structure other than a single bond, ^X2 increases the flexibility of the sulfonium salt and the iodonium salt and improves the ability to quench the acid.

By photolysis, the sulfonium or iodonium is decomposed to become an iodinated monovalent aromatic carboxylic acid bonded to the polymer. The iodinated monovalent aromatic carboxylic acid has the characteristic of small swelling in an alkaline developer. If it is a low swelling property, it can reduce the decrease in dimensional uniformity caused by swelling during the development of the contact hole pattern, or reduce the stress on the pattern during the spin drying for drying the line and space pattern after rinsing with pure water, and reduce the pattern collapse after the pattern is formed.

The repeating unit a is a quencher having a substituted or unsubstituted iodinated univalent aromatic carboxylic acid sulfonium salt or iodonium salt structure, and is a quencher-bonded polymer. The quencher-bonded polymer has a high effect of inhibiting acid diffusion and has excellent resolution as described above. Thereby, high resolution, low LWR and low CDU can be achieved.

The monomers providing the repeating unit a1 represented by the general formula (a)-1 and the repeating unit a2 represented by the general formula (a)-2 may include the monomers of the present invention described above. In addition, the anion portion thereof may include the following, but is not limited thereto. In the following formula, ^RA is the same as described above.

[Chemistry 11]

[Chemistry 12]

[Chemistry 13]

[Chemistry 14]

[Chemistry 15]

[Chemistry 16]

[Chemistry 17]

[Chemistry 18]

[Chemistry 19]

[Chemistry 20]

[Chemistry 21]

[Chemistry 22]

[Chemistry 23]

[Chemistry 24]

[Chemistry 25]

[Chemistry 26]

Examples of the cation of the sulfonium salt represented by the general formula (a)-1 include the following, but are not limited thereto.

[Chemistry 27]

[Chemistry 28]

[Chemistry 29]

[Chemistry 30]

[Chemistry 31]

[Chemistry 32]

[Chemistry 33]

[Chemistry 34]

[Chemistry 35]

[Chemistry 36]

[Chemistry 37]

[Chemistry 38]

[Chemistry 39]

[Chemistry 40]

[Chemistry 41]

[Chemistry 42]

[Chemistry 43]

[Chemistry 44]

[Chemistry 45]

[Chemistry 46]

[Chemistry 47]

[Chemistry 48]

[Chemistry 49]

Examples of the cation of the iodonium salt represented by the general formula (a)-2 include the following, but are not limited thereto.

[Chemistry 50]

In order to improve the dissolution contrast, the resist material preferably further contains a repeating unit b in which the hydrogen atoms of either or both of a carboxyl group and a phenolic hydroxyl group are substituted with an acid-labile group. In addition, the repeating unit b is preferably at least one selected from the repeating units represented by the following general formulas (b1) and (b2). Hereinafter, the repeating unit in which the hydrogen atom of the carboxyl group is substituted with an acid-labile group is referred to as a repeating unit b1, and the repeating unit in which the hydrogen atom of the phenolic hydroxyl group is substituted with an acid-labile group is referred to as a repeating unit b2.

Examples of the repeating units b1 and b2 include those represented by the following general formulae (b1) and (b2), respectively.

[Chemistry 51]

In the formula, ^RA is independently a hydrogen atom or a methyl group. ^Y1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and having an ester bond, an ether bond, or a lactone ring. ^Y2 is a single bond, an ester bond, or an amide bond. ^R11 and ^R12 are acid-labile groups. ^R13 is a fluorine atom, a trifluoromethyl group, a cyano group, or an alkyl group having 1 to 6 carbon atoms. ^R14 is a single bond or a linear or branched alkanediyl group having 1 to 6 carbon atoms, and a portion of the carbon atoms thereof may be substituted by an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4.

In the formula, ^RA is independently a hydrogen atom or a methyl group, preferably a methyl group. ^Y1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and having an ester bond, an ether bond, or a lactone ring, preferably a single bond or a phenylene group. ^Y2 is a single bond, an ester bond, or an amide bond, preferably a single bond. ^R11 and ^R12 are acid-labile groups. ^R13 is a fluorine atom, a trifluoromethyl group, a cyano group, or an alkyl group having 1 to 6 carbon atoms, preferably a fluorine atom. ^R14 is a single bond or a linear or branched alkanediyl group having 1 to 6 carbon atoms, and a part of the carbon atoms thereof may be substituted by an ether bond or an ester bond, preferably an ester bond. a is 1 or 2, preferably 1. b is an integer of 0 to 4, preferably 0 or 1.

Examples of the monomers providing the repeating unit b1 include, but are not limited to, the following. In the following formula, ^RA and ^R11 are the same as those described above.

[Chemistry 52]

[Chemistry 53]

Examples of the monomers providing the repeating unit b2 include, but are not limited to, the following. In the following formula, ^RA and ^R12 are the same as those described above.

[Chemistry 54]

The acid-labile group represented by R ¹¹ or R ¹² can be selected from various options, and examples thereof include those represented by the following general formulas (AL-1) to (AL-3).

[Chemistry 55]

In the general formula (AL-1), c is an integer of 0 to 6. ^RL1 is a tertiary hydrocarbon group having 4 to 61 carbon atoms, preferably 4 to 15 carbon atoms, a trihydrocarbylsilyl group in which each hydrocarbon group is a saturated hydrocarbon group having 1 to 6 carbon atoms, a saturated hydrocarbon group having 4 to 20 carbon atoms containing a carbonyl group, an ether bond or an ester bond, or a group represented by the general formula (AL-3).

The tertiary hydrocarbon group represented by R ^L1 may be saturated or unsaturated, and may be branched or cyclic. Specific examples thereof include: tert-butyl, tert-amyl, 1,1-diethylpropyl, 1-ethylcyclopentyl, 1-butylcyclopentyl, 1-ethylcyclohexyl, 1-butylcyclohexyl, 1-ethyl-2-cyclopentenyl, 1-ethyl-2-cyclohexenyl, 2-methyl-2-adamantyl, etc. The aforementioned trihydrocarbylsilyl group includes: trimethylsilyl, triethylsilyl, dimethyl-tert-butylsilyl, etc. The aforementioned saturated hydrocarbon group containing a carbonyl group, an ether bond or an ester bond may be any of straight chain, branched or cyclic, preferably cyclic, and specific examples thereof include 3-oxocyclohexyl, 4-methyl-2-oxooxan-4-yl, 5-methyl-2-oxooxan-5-yl, 2-tetrahydropyranyl, 2-tetrahydrofuranyl and the like.

Examples of the acid-labile group represented by the general formula (AL-1) include tert-butoxycarbonyl, tert-butoxycarbonylmethyl, tert-amyloxycarbonyl, tert-amyloxycarbonylmethyl, 1,1-diethylpropyloxycarbonyl, 1,1-diethylpropyloxycarbonylmethyl, 1-ethylcyclopentyloxycarbonyl, 1-ethylcyclopentyloxycarbonylmethyl, 1-ethyl-2-cyclopentenyloxycarbonyl, 1-ethyl-2-cyclopentenyloxycarbonylmethyl, 1-ethoxyethoxycarbonylmethyl, 2-tetrahydropyranyloxycarbonylmethyl, and 2-tetrahydrofuranyloxycarbonylmethyl.

Examples of the acid-labile group represented by the general formula (AL-1) include groups represented by the following general formulae (AL-1)-1 to (AL-1)-10.

[Chemistry 56]

In the formula, the dotted lines are atomic bonds.

In the general formulae (AL-1)-1 to (AL-1)-10, c is the same as described above. ^RL8 is independently a saturated hydrocarbon group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. ^RL9 is a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbon atoms. ^RL10 is a saturated hydrocarbon group having 2 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbon group may be linear, branched or cyclic.

In the general formula (AL-2), ^RL2 and ^RL3 are each independently a hydrogen atom or a saturated hydrocarbon group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms. The saturated hydrocarbon group may be linear, branched or cyclic, and specific examples thereof include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, cyclopentyl, cyclohexyl, 2-ethylhexyl, n-octyl and the like.

In the general formula (AL-2), ^RL4 is a hydrocarbon group having 1 to 18 carbon atoms and preferably 1 to 10 carbon atoms, which may contain heteroatoms. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Examples of the hydrocarbon group include saturated hydrocarbon groups having 1 to 18 carbon atoms, and some of the hydrogen atoms thereof may be substituted with hydroxyl, alkoxy, oxo, amino, alkylamino, or the like. Examples of such substituted saturated hydrocarbon groups include those shown below.

[Chemistry 57]

In the formula, the dotted lines are atomic bonds.

^RL2 and ^RL3 , ^RL2 and ^RL4 , or ^RL3 and ^RL4 may also be bonded to each other and form a ring together with the carbon atom to which they are bonded or together with the carbon atom and the oxygen atom. In this case, ^RL2 and ^RL3 , ^RL2 and ^RL4 , or ^RL3 and ^RL4 participating in the formation of the ring are each independently an alkanediyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms. The carbon number of the ring formed by these bonding is preferably 3 to 10, more preferably 4 to 10.

Among the acid-labile groups represented by the general formula (AL-2), linear or branched ones include those represented by the following formulae (AL-2)-1 to (AL-2)-69, but are not limited thereto. In the following formulae, the dotted lines represent atomic bonds.

[Chemistry 58]

[Chemistry 59]

[Chemistry 60]

[Chemistry 61]

Among the acid-labile groups represented by the general formula (AL-2), cyclic ones include tetrahydrofuran-2-yl, 2-methyltetrahydrofuran-2-yl, tetrahydropyran-2-yl, and 2-methyltetrahydropyran-2-yl.

Examples of the acid-labile group include groups represented by the following general formula (AL-2a) or (AL-2b): The acid-labile group can also allow the resist material to undergo intermolecular or intramolecular crosslinking.

[Chemistry 62]

In the formula, the dotted lines are atomic bonds.

In the general formula (AL-2a) or (AL-2b), R ^L11 and R ^L12 are each independently a hydrogen atom or a saturated hydrocarbon group having 1 to 8 carbon atoms. The saturated hydrocarbon group may be any of linear, branched, or cyclic. Furthermore, R ^L11 and R ^L12 may be bonded to each other and form a ring together with the carbon atoms to which they are bonded. In this case, R ^L11 and R ^L12 are each independently an alkanediyl group having 1 to 8 carbon atoms. ^{R L13} is each independently a saturated alkylene group having 1 to 10 carbon atoms. The saturated alkylene group may be any of linear, branched, or cyclic. d and e are each independently an integer of 0 to 10, preferably an integer of 0 to 5, and f is an integer of 1 to 7, preferably an integer of 1 to 3.

In the general formula (AL-2a) or (AL-2b), L ^A is an aliphatic saturated hydrocarbon group having 1 to 50 carbon atoms and having a valence of (f+1) , an alicyclic saturated hydrocarbon group having 3 to 50 carbon atoms and having a valence of (f+1) , an aromatic hydrocarbon group having 6 to 50 carbon atoms and having a valence of (f+1) , or a heterocyclic group having 3 to 50 carbon atoms and having a valence of (f+1) . In addition, part of the carbon atoms of these groups may be substituted by a heteroatom-containing group, and part of the hydrogen atoms bonded to the carbon atoms of these groups may be substituted by a hydroxyl group, a carboxyl group, an acyl group, or a fluorine atom. ^{L A} is preferably a saturated hydrocarbon group such as a saturated hydrocarbon group having 1 to 20 carbon atoms, a trivalent saturated hydrocarbon group, a tetravalent saturated hydrocarbon group, or an arylene group having 6 to 30 carbon atoms. The saturated hydrocarbon group may be straight chain, branched, or cyclic. L ^B is -C(=O)-O-, -NH-C(=O)-O-, or -NH-C(=O)-NH-.

Examples of the cross-linked acetal group represented by the general formula (AL-2a) or (AL-2b) include groups represented by the following formulae (AL-2)-70 to (AL-2)-77.

[Chemistry 63]

In the formula, the dotted lines are atomic bonds.

In the general formula (AL-3), R ^L5 , R ^L6 and R ^L7 are each independently a hydrocarbon group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The aforementioned hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: an alkyl group having 1 to 20 carbon atoms, a cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a cyclic unsaturated hydrocarbon group having 3 to 20 carbon atoms, and an aryl group having 6 to 10 carbon atoms. In addition, R ^L5 and R ^L6 , R ^L5 and R ^L7 , or R ^L6 and R ^L7 may be bonded to each other and form an alicyclic ring having 3 to 20 carbon atoms together with the carbon atoms to which they are bonded.

Examples of the group represented by the general formula (AL-3) include tert-butyl, 1,1-diethylpropyl, 1-ethylnorbornyl, 1-methylcyclopentyl, 1-isopropylcyclopentyl, 1-ethylcyclopentyl, 1-methylcyclohexyl, 2-(2-methyl)adamantyl, 2-(2-ethyl)adamantyl, and tert-pentyl.

Examples of the group represented by the general formula (AL-3) include groups represented by the following general formulae (AL-3)-1 to (AL-3)-19.

[Chemistry 64]

In the formula, the dotted lines are atomic bonds.

In the general formulae (AL-3)-1 to (AL-3)-19, ^RL14 is independently a saturated hydrocarbon group having 1 to 8 carbon atoms or an aryl group having 6 to 20 carbon atoms. ^RL15 and ^RL17 are independently a hydrogen atom or a saturated hydrocarbon group having 1 to 20 carbon atoms. ^RL16 is an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbon group may be linear, branched or cyclic. The aryl group is preferably a phenyl group or the like. ^RF is a fluorine atom or a trifluoromethyl group. g is an integer of 1 to 5.

In addition, the acid-labile group includes a group represented by the following general formula (AL-3)-20 or (AL-3)-21. The acid-labile group can also crosslink the resist material intramolecularly or intermolecularly.

[Chemistry 65]

In the formula, the dotted lines are atomic bonds.

In the general formulae (AL-3)-20 and (AL-3)-21, R ^L14 is the same as described above. R ^L18 is a saturated alkylene group having a valence of (h+1) and having 1 to 20 carbon atoms or an arylene group having a valence of (h+1) and having 6 to 20 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms. The saturated alkylene group may be linear, branched, or cyclic. h is an integer of 1 to 3.

Examples of the monomer providing a repeating unit containing an acid-labile group represented by the general formula (AL-3) include (meth)acrylates containing an exo-stereoisomer structure represented by the following general formula (AL-3)-22.

[Chemistry 66]

In the general formula (AL-3)-22, ^RA is the same as described above. ^RLc1 is a saturated hydrocarbon group having 1 to 8 carbon atoms or an aryl group having 6 to 20 carbon atoms which may be substituted. The saturated hydrocarbon group may be linear, branched or cyclic. ^RLc2 to ^RLc11 are each independently a hydrogen atom or a hydrocarbon group having 1 to 15 carbon atoms which may contain a heteroatom. Examples of the heteroatom include an oxygen atom and the like. Examples of the hydrocarbon group include an alkyl group having 1 to 15 carbon atoms, an aryl group having 6 to 15 carbon atoms and the like. R ^Lc2 and R ^Lc3 , R ^Lc4 and R ^Lc6 , R ^Lc4 and R ^Lc7 , R ^Lc5 and R ^Lc7 , R ^Lc5 and R ^Lc11 , R ^Lc6 and R ^Lc10 , R ^Lc8 and R ^Lc9 , or R ^Lc9 and R ^Lc10 may also be bonded to each other and form a ring together with the carbon atoms to which they are bonded. In this case, the group involved in the bond is a alkylene group having 1 to 15 carbon atoms and may contain a heteroatom. Furthermore, R ^Lc2 and R ^Lc11 , R ^Lc8 and R ^Lc11 , or R ^Lc4 and R ^Lc6 may be bonded to adjacent carbon atoms without any group in between to form a double bond. In addition, the mirror image is also represented by this formula.

Here, the monomers providing the repeating unit represented by the general formula (AL-3)-22 include those described in Japanese Patent Application Publication No. 2000-327633, etc. Specifically, the following may be mentioned, but it is not limited thereto. In the following formula, ^RA is the same as above.

[Chemistry 67]

Examples of the monomer providing a repeating unit containing an acid-labile group represented by the general formula (AL-3) include (meth)acrylates containing a furandiyl group, a tetrahydrofurandiyl group or an oxanorbornanediyl group represented by the following general formula (AL-3)-23.

[Chemistry 68]

In the general formula (AL-3)-23, ^RA is the same as described above. ^RLc12 and ^RLc13 are each independently a hydrocarbon group having 1 to 10 carbon atoms. ^RLc12 and ^RLc13 may also be bonded to each other and form an alicyclic ring together with the carbon atoms to which they are bonded. ^RLc14 is furandiyl, tetrahydrofurandiyl or oxa-norbornanediyl. ^RLc15 is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms which may contain a heteroatom. The aforementioned hydrocarbon group may be any of a straight chain, a branched shape, and a cyclic shape. Specific examples thereof include saturated hydrocarbon groups having 1 to 10 carbon atoms, and the like.

Examples of monomers that provide repeating units represented by the general formula (AL-3)-23 include, but are not limited to, the following: In the following formula, ^RA is the same as above, Ac is an acetyl group, and Me is a methyl group.

[Chemistry 69]

[Chemistry 70]

The aforementioned resist material may further contain a repeating unit c having an adhesive group selected from a hydroxyl group, a carboxyl group, a lactone ring, a carbonate group, a thiocarbonate group, a carbonyl group, a cyclic acetal group, an ether bond, an ester bond, a sulfonate bond, a cyano group, an amide group, -O-C(=O)-S-, and -O-C(=O)-NH-.

Examples of the monomers providing the repeating unit c include, but are not limited to, the following. In the following formula, ^RA is the same as described above.

[Chemistry 71]

[Chemistry 72]

[Chemistry 73]

[Chemistry 74]

[Chemistry 75]

[Chemistry 76]

[Chemistry 77]

[Chemistry 78]

The aforementioned resist material may also further contain a repeating unit d derived from an onium salt containing a polymerizable unsaturated bond. The ideal repeating unit d can be listed as: a repeating unit represented by the following general formula (d1) (hereinafter also referred to as repeating unit d1), a repeating unit represented by the following general formula (d2) (hereinafter also referred to as repeating unit d2), and a repeating unit represented by the following general formula (d3) (hereinafter also referred to as repeating unit d3). In addition, the repeating units d1 to d3 may be used alone or in combination of two or more. That is, the aforementioned resist material preferably further contains at least one repeating unit d selected from the repeating units represented by the following general formulas (d1) to (d3).

[Chemistry 79]

In the formula, ^RA is independently a hydrogen atom or a methyl group. ^Z1 is a single bond, a phenylene group, ^-OZ11- , -C(=O) ^-OZ11- or -C(=O)-NH- ^Z11- , ^Z11 is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms or a phenylene group, and may contain one or more selected from a carbonyl group, an ester bond, an ether bond, and a hydroxyl group. ^{Z2A is a single bond or an ester bond. Z2B is} a single bond or a divalent group having 1 to 12 carbon atoms, and may contain one or more selected from an ester bond, an ether bond, a lactone ring, a bromine atom, and an iodine atom. ^Z3 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, ^-OZ31- , -C(=O) ^-OZ31- or -C(=O)-NH- ^Z31- , ^Z31 is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms or a phenylene group, and may contain one or more selected from a carbonyl group, an ester bond, an ether bond, a halogen atom, and a hydroxyl group. ^Rf1 to ^Rf4 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of them is a fluorine atom. ^R21 to ^R28 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. In addition, any two of ^R23 , ^R24 and ^R25 or any two of ^R26 , ^R27 and ^R28 may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. ^M- is a non-nucleophilic counter ion.

In the formula, ^RA is independently a hydrogen atom or a methyl group, preferably a methyl group. ^Z1 is a single bond, a phenylene group, ^-OZ11- , -C(=O) ^-OZ11- or -C(=O)-NH- ^Z11- , ^Z11 is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms or a phenylene group, and may contain at least one selected from a carbonyl group, an ester bond, an ether bond, and a hydroxyl group, and may be preferably ether. ^Z2A is a single bond or an ester bond, and may be preferably an ester bond. ^Z2B is a single bond or a divalent group having 1 to 12 carbon atoms, and may contain at least one selected from an ester bond, an ether bond, a lactone ring, a bromine atom, and an iodine atom. ^Z3 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, ^-OZ31- , -C(=O) ^-OZ31- or -C(=O)-NH- ^Z31- , ^Z31 is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms or a phenylene group, and may contain at least one selected from a carbonyl group, an ester bond, an ether bond, a halogen atom and a hydroxyl group. ^Rf1 to ^Rf4 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, and at least one of them is a fluorine atom.

In general formula (d2), ^Rf1 to ^Rf4 are independently hydrogen, fluorine or trifluoromethyl, and at least one of them is a fluorine atom. In particular, at least one of ^Rf3 and ^Rf4 is preferably a fluorine atom, and more preferably ^{both Rf3} and ^Rf4 are fluorine atoms.

In the general formulae (d1) to (d3), R ²¹ to R ²⁸ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. In addition, any two of R ²³ , R ²⁴ and R ²⁵ or any two of R ²⁶ , R ²⁷ and R ²⁸ may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. The monovalent hydrocarbon group may be linear, branched or cyclic, and specific examples thereof include an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms. Furthermore, part or all of the hydrogen atoms in these groups may be substituted by an alkyl group having 1 to 10 carbon atoms, a halogen atom, a trifluoromethyl group, a cyano group, a nitro group, a hydroxyl group, a mercapto group, an alkoxy group having 1 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 10 carbon atoms, or an acyloxy group having 2 to 10 carbon atoms, and part of the carbon atoms in these groups may be substituted by a carbonyl group, an ether bond, or an ester bond.

In the general formulae (d2) and (d3), specific examples of the sulfonium cation include the same examples as those exemplified as the cation of the sulfonium salt represented by the general formula (1-1) described later.

In the general formula (d1), M- ^is a non-nucleophilic counter ion. Examples of the non-nucleophilic counter ions include halide ions such as chloride ions and bromide ions; fluoroalkyl sulfonate ions such as trifluoromethanesulfonate ions, 1,1,1-trifluoroethanesulfonate ions, and nonafluorobutanesulfonate ions; aryl sulfonate ions such as toluenesulfonate ions, benzenesulfonate ions, 4-fluorobenzenesulfonate ions, and 1,2,3,4,5-pentafluorobenzenesulfonate ions; alkyl sulfonate ions such as methanesulfonate ions and butanesulfonate ions; imide acid ions such as bis(trifluoromethylsulfonyl)imide ions, bis(perfluoroethylsulfonyl)imide ions, and bis(perfluorobutylsulfonyl)imide ions; methylated acid ions such as tris(trifluoromethylsulfonyl)methide ions and tris(perfluoroethylsulfonyl)methide ions.

The aforementioned non-nucleophilic relative ions can further be listed as follows: sulfonate ions represented by the following general formula (d1-1) in which the α-position is substituted with a fluorine atom, sulfonate ions represented by the following general formula (d1-2) in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group, etc.

[Chemistry 80]

R ³¹ -CF ₂ -SO ₃ ^- (d1-1)

In the general formula (d1-1), R ³¹ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and may contain an ether bond, an ester bond, a carbonyl group, a lactone ring, or a fluorine atom. The alkyl group and the alkenyl group may be straight-chain, branched, or cyclic.

In the general formula (d1-2), R ³² is a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an acyl group having 2 to 30 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aryloxy group having 6 to 20 carbon atoms, and may contain an ether bond, an ester bond, a carbonyl group, or a lactone ring. The alkyl group, acyl group, and alkenyl group may be straight-chain, branched, or cyclic.

Furthermore, it is preferred that the aforementioned Z ^2B contains at least one iodine atom.

Examples of the monomers providing the repeating unit d1 include, but are not limited to, the following: In the following formula, ^RA and M- are the same as those described above.

[Chemistry 81]

The monomers providing the repeating unit d2 include, but are not limited to, the following. In the following formula, ^RA is the same as described above.

[Chemistry 82]

[Chemistry 83]

[Chemistry 84]

[Chemistry 85]

[Chemistry 86]

Furthermore, the monomer providing the repeating unit d2 is preferably one having an anion as shown below: In the following formula, ^RA is the same as above.

[Chemistry 87]

[Chemistry 88]

[Chemistry 89]

[Chemistry 90]

[Chemistry 91]

[Chemistry 92]

[Chemistry 93]

[Chemistry 94]

Examples of the monomers providing the repeating unit d3 include, but are not limited to, the following. In the following formula, ^RA is the same as described above.

[Chemistry 95]

[Chemistry 96]

Repeating units d1 to d3 function as an acid generator. By bonding the acid generator to the polymer main chain, the acid diffusion can be reduced and the reduction in resolution caused by the blurring of the acid diffusion can be prevented. In addition, the acid generator can be evenly dispersed to improve the LWR. In addition, when using a resist material containing repeating unit d, the addition of the additive acid generator described later can be omitted.

In the resist material of the present invention, by copolymerizing the repeating unit a having a quencher function of a substituted or unsubstituted iodinated monovalent aromatic carboxylic acid sulfonium salt or iodonium salt bonded to the polymer main chain via an ester bond, and the repeating unit d having an acid generator function of d1 to d3, all functions can be contained in one polymer. In this case, the only materials added other than the polymer may be an organic solvent or a surfactant, and since it is composed of simple materials, it has the advantage of high productivity.

The polymerization rate of the quencher of the sulfonium salt or iodonium salt of the iodonium salt of the iodonium salt having a double bond is about the same as the polymerization rate of the acid generator of the sulfonium salt or iodonium salt, so the quencher and the acid generator are uniformly present in the polymer, thereby improving the edge roughness after development. When the anion part of the acid generator contains iodine, the edge roughness is further improved by utilizing the improvement of the contrast during acid generation due to the increase in the number of absorbed photons. The repeating unit a of the sulfonium salt or iodonium salt of the iodonium salt of the iodonium salt having an iodine in the resist material of the present invention has the following effect: the number of absorbed photons due to the absorption of iodine is increased, thereby improving the contrast of the decomposition of the quencher and achieving the improvement of the edge roughness.

The resist material may further contain a repeating unit e which does not contain an amino group but contains an iodine atom. Examples of monomers providing the repeating unit e include, but are not limited to, the following. In the following formula, ^RA is the same as above.

[Chemistry 97]

[Chemistry 98]

The resist material may contain a repeating unit f other than the repeating unit mentioned above. Examples of the repeating unit f include those derived from styrene, vinylnaphthalene, indene, acenaphthene, coumarin, coumarone, and the like.

In the resist material, the content ratio of the repeating units a1, a2, b1, b2, c, d1, d2, d3, e and f is preferably 0≤a1≤1.0, 0≤a2≤1.0, 0<a1+a2≤1.0, 0≤b1≤0.5, 0≤b2≤0.5, 0≤b1+b2≤0.9, 0≤c≤0.9, 0≤d1≤0.5, 0≤d2≤0.5, 0≤d3≤0.5, 0≤d1+d2+d3≤0.5, 0≤e≤0.5 and 0≤f≤0.5, and is 0.001≤a1≤0.8, 0.001≤a2≤0.8, 0.001≤a1+a2≤0.8, 0≤b1≤0.8, 0≤b2 ≤0.8, 0.1≤b1+b2≤0.8, 0≤c≤0.8, 0≤d1≤0.4, 0≤d2≤0.4, 0≤d3≤0.4, 0≤d1+d2+d3≤0.4, 0≤e≤0.4 and 0≤f≤0.4 are more preferred, and 0.005≤a1≤0.7, 0.005≤a2≤0.7, 0.005≤a1+a2≤0.7, 0≤b1≤0.7, 0≤b2≤0.7, 0≤b1+b2≤0.7, 0≤c≤0.7, 0≤d1≤0.3, 0≤d2≤0.3, 0≤d3≤0.3, 0≤d1+d2+d3≤0.3, 0≤e≤0.3 and 0≤f≤0.3 are even more preferred. But, a1+a2+b1+b2+c+d1+d2+d3+e+f=1.0.

When synthesizing the resist material, for example, a monomer providing the repeating unit is added with a radical polymerization initiator in an organic solvent, and then heated to perform polymerization.

Examples of organic solvents used in the polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, dioxane, propylene glycol monomethyl ether, γ-butyrolactone, and mixed solvents thereof. Examples of polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-methylpropionic acid) dimethyl ester, benzoyl peroxide, lauroyl peroxide, and the like. The polymerization temperature is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

When a monomer containing a hydroxyl group is copolymerized, the hydroxyl group can be replaced with an acetal group such as ethoxyethoxy that is easily deprotected by an acid during the polymerization, and then deprotected using a weak acid and water after the polymerization. Alternatively, the hydroxyl group can be replaced with an acetyl group, a formyl group, a pivaloyl group, etc., and then alkaline hydrolysis can be performed after the polymerization.

When hydroxystyrene and hydroxyvinylnaphthalene are copolymerized, acetoxystyrene and acetoxyvinylnaphthalene may be used instead of hydroxystyrene and hydroxyvinylnaphthalene, and after polymerization, the acetoxy group may be deprotected by the above-mentioned alkaline hydrolysis to obtain hydroxystyrene and hydroxyvinylnaphthalene.

The base used in the alkaline hydrolysis may be aqueous ammonia, triethylamine, etc. The reaction temperature is preferably -20 to 100°C, more preferably 0 to 60°C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

The polystyrene-equivalent weight average molecular weight (Mw) of the resist material measured by gel permeation chromatography (GPC) using THF as a solvent is preferably 1,000 to 500,000, more preferably 1,000 to 100,000, and even more preferably 2,000 to 30,000. If Mw is 1,000 or more, the resist material has excellent heat resistance, and if Mw is 500,000 or less, alkali solubility is maintained and tailing does not occur after pattern formation.

In addition, when the molecular weight distribution (Mw/Mn) of the aforementioned resist material is wide, there is a concern that foreign matter may be observed on the pattern after exposure or the shape of the pattern may deteriorate due to the presence of low molecular weight and high molecular weight polymers. As the pattern rules become finer, the influence of Mw and Mw/Mn is also likely to become greater. Therefore, in order to obtain a resist material suitable for use in a fine pattern size, the Mw/Mn of the aforementioned resist material is preferably 1.0 to 2.0, and a particularly preferred narrow distribution is 1.0 to 1.5.

In order to obtain a narrowly dispersed polymer, not only conventional radical polymerization but also living radical polymerization can be used. Examples of living radical polymerization include living radical polymerization using nitroxide radicals (Nitroxide-Mediated Radical Polymerization: NMP), atom transfer radical polymerization (Atom Transfer Radical Polymerization: ATRP), and reversible addition-fragmentation chain transfer (Reversible Addition-Fragmentation Chain Transfer: RAFT) polymerization.

The resist material may include two or more polymers having different composition ratios, Mw, and Mw/Mn. In addition, a polymer containing a repeating unit a and a polymer not containing a repeating unit a may be mixed.

[Resist composition]

In addition, the present invention provides a resist composition, which is a resist composition containing the resist material described above. The resist composition of the present invention preferably further contains one or more selected from a photoacid generator, an organic solvent, a quencher, and a surfactant. The following describes the components contained in the resist composition.

[Acid generator]

The resist material of the present invention may further contain an acid generator (hereinafter also referred to as an additive acid generator) that generates a strong acid. Here, the so-called strong acid means a compound having an acidity sufficient to cause a deprotection reaction of an acid-labile group of the resist material. Examples of the aforementioned acid generator include compounds (photoacid generators) that are responsive to active light or radiation and generate an acid. If the photoacid generator is a compound that generates an acid due to high-energy radiation irradiation, it can be any compound, and it is preferably one that generates sulfonic acid, imidic acid or methylated acid. Ideal photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate acid generators, etc. Specific examples of photoacid generators include those described in paragraphs [0122] to [0142] of Japanese Patent Publication No. 2008-111103.

Furthermore, as the photoacid generator, a sulfonium salt represented by the following general formula (1-1) or an iodonium salt represented by the following general formula (1-2) can also be preferably used.

[Chemistry 99]

In the general formulae (1-1) and (1-2), ^R101 to ^R105 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. In addition, any two of ^R101 , ^R102 and ^R103 may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. The monovalent hydrocarbon group may be linear, branched or cyclic, and specific examples thereof include the same examples as those mentioned above.

In the general formulae (1-1) and (1-2), X- ^is an anion selected from the group consisting of the following general formulae (1A) to (1D).

[Chemical 100]

In the general formula (1A), R ^fa is a hydrocarbon group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same examples as those described below for the hydrocarbon group represented by R ¹⁰⁷ in the general formula (1A').

The anion represented by the general formula (1A) is preferably represented by the following general formula (1A').

[Chemistry 101]

In the general formula (1A'), ^R106 is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. ^R107 is a hydrocarbon group having 1 to 38 carbon atoms which may contain a hetero atom. The hetero atom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc., and is more preferably an oxygen atom. The hydrocarbon group is particularly preferably one having 6 to 30 carbon atoms from the viewpoint of obtaining a high resolution when forming a fine pattern.

The hydrocarbon group represented by R ¹⁰⁷ may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include: alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and eicosyl; cyclic saturated hydrocarbon groups such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecanyl, tetracyclododecyl, tetracyclododecylmethyl, and dicyclohexylmethyl; unsaturated hydrocarbon groups such as allyl and 3-cyclohexenyl; aryl groups such as phenyl, 1-naphthyl, and 2-naphthyl; aralkyl groups such as benzyl and diphenylmethyl; and the like.

Furthermore, part or all of the hydrogen atoms of these groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of the carbon atoms of these groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, hydroxyl groups, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate groups, lactone rings, sultone rings, carboxylic anhydrides, and haloalkyl groups may be contained. Examples of heteroatom-containing hydrocarbon groups include tetrahydrofuranyl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetamidomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, and 3-oxocyclohexyl.

The synthesis of the sulfonium salt containing the anion represented by the general formula (1A') is described in Japanese Patent Application Publication No. 2007-145797, Japanese Patent Application Publication No. 2008-106045, Japanese Patent Application Publication No. 2009-007327, Japanese Patent Application Publication No. 2009-258695, etc. Also, the sulfonium salts described in Japanese Patent Application Publication No. 2010-215608, Japanese Patent Application Publication No. 2012-041320, Japanese Patent Application Publication No. 2012-106986, Japanese Patent Application Publication No. 2012-153644, etc. can be preferably used.

Examples of the anion represented by the general formula (1A) include the same examples as those exemplified as the anion represented by the formula (1A) in JP-A-2018-197853.

In the general formula (1B), ^Rfb1 and ^Rfb2 are each independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same examples as those exemplified in the description of ^R107 in the general formula (1A'). ^Rfb1 and ^Rfb2 are preferably fluorine atoms or linear fluorinated alkyl groups having 1 to 4 carbon atoms. Furthermore, ^Rfb1 and ^Rfb2 may be bonded to each other and form a ring together with the group to which they are bonded (-CF2 _{- SO2} -N ^-- _SO2 - _CF2- ), in which case the group obtained by bonding ^Rfb1 and ^Rfb2 to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

In the general formula (1C), ^Rfc1 , ^Rfc2 and ^Rfc3 are each independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include the same examples as those exemplified in the description of ^R107 in the general formula (1A'). ^Rfc1 , ^Rfc2 and ^Rfc3 are preferably fluorine atoms or linear fluorinated alkyl groups having 1 to 4 carbon atoms. Furthermore, ^Rfc1 and ^Rfc2 may be bonded to each other and form a ring together with the group to which they are bonded (-CF2 _{- SO2} -C ^-- _SO2 - _CF2- ), in which case the group obtained by bonding ^Rfc1 and ^Rfc2 to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

In the general formula (1D), ^Rfd is a hydrocarbon group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same examples as those exemplified in the description of ^R107 in the general formula (1A').

The synthesis of the sulfonium salt containing the anion represented by the general formula (1D) is described in detail in Japanese Unexamined Patent Publication Nos. 2010-215608 and 2014-133723.

Examples of the anion represented by the general formula (1D) include the same examples as those exemplified as the anion represented by the formula (1D) in JP-A-2018-197853.

In addition, the photoacid generator containing the anion represented by the general formula (1D) has no fluorine at the α-position of the sulfonic group but has two trifluoromethyl groups at the β-position, and thus has acidity sufficient to cut off the acid-labile groups in the resist material. Therefore, it can be used as a photoacid generator.

Furthermore, as the photoacid generator, a photoacid generator represented by the following general formula (2) can also be preferably used.

[Chemistry 102]

In the general formula (2), ^R201 and ^R202 are each independently a hydrocarbon group having 1 to 30 carbon atoms which may contain a hetero atom. ^R203 may be a hydrocarbon ene group having 1 to 30 carbon atoms which may contain a hetero atom. Furthermore, ^R201 and ^R202 or ^R201 and ^R203 may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. In this case, the aforementioned ring may be the same as those exemplified in the description of the general formula (1-1) as the ring that can be formed when ^R101 and ^R102 are bonded to each other and together with the sulfur atom to which they are bonded.

The hydrocarbon group represented by R ²⁰¹ and R ²⁰² may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include: alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclic saturated hydrocarbon groups such as cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo[5.2.1.0 ^2,6 ]decyl, and adamantyl; and aryl groups such as phenyl, tolyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, tert-butylnaphthyl, and anthracenyl. Furthermore, part or all of the hydrogen atoms of these groups may be substituted by groups containing hetero atoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of the carbon atoms of these groups may be substituted by groups containing hetero atoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, they may contain hydroxyl groups, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate groups, lactone rings, sultone rings, carboxylic anhydrides, haloalkyl groups, and the like.

The alkylene group represented by R ²⁰³ may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include: methylene, ethylene, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, Alkanediyl groups such as heptadecan-1,17-diyl; cyclic saturated alkylene groups such as cyclopentanediyl, cyclohexanediyl, norbornanediyl and adamantanediyl; arylene groups such as phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene and tert-butylnaphthylene; and the like. Furthermore, part or all of the hydrogen atoms of these groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of the carbon atoms of these groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, hydroxyl groups, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate groups, lactone rings, sultone rings, carboxylic anhydrides, haloalkyl groups, etc. are contained. The aforementioned heteroatoms are preferably oxygen atoms.

In the general formula (2), ^L1 is a single bond, an ether bond, or a carbonylene group having 1 to 20 carbon atoms which may contain a hetero atom. The aforementioned carbonylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same examples as those exemplified as the carbonylene group represented by ^R203 .

In the general formula (2), ^XA , ^XB , ^XC and ^XD are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group. However, at least one of ^XA , ^XB , ^XC and ^XD is a fluorine atom or a trifluoromethyl group.

In the general formula (2), k is an integer of 0-3.

The photoacid generator represented by the general formula (2) is preferably represented by the following general formula (2').

[Chemistry 103]

In the general formula (2'), ^L1 is the same as described above. ^RHF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. ^R301 , ^R302 and ^R303 are each independently a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include the same examples as those exemplified in the description of ^R107 in the general formula (1A'). x and y are each independently an integer of 0 to 5, and z is an integer of 0 to 4.

Examples of the photo-acid generator represented by the general formula (2) include the same examples as those exemplified as the photo-acid generator represented by the formula (2) in JP-A-2017-026980.

Among the above-mentioned photoacid generators, those containing anions represented by general formula (1A') or (1D) are particularly preferred because they have low acid diffusion and excellent solubility in resist solvents. Also, those represented by general formula (2') are particularly preferred because they have extremely low acid diffusion.

Furthermore, the photoacid generator may be a sulfonium salt or iodonium salt having an anion containing an aromatic ring substituted with an iodine atom or a bromine atom. Examples of such salts include those represented by the following general formula (3-1) or (3-2).

[Chemistry 104]

In general formulae (3-1) and (3-2), p is an integer satisfying 1≤p≤3. q and r are integers satisfying 1≤q≤5, 0≤r≤3 and 1≤q+r≤5. q is preferably an integer satisfying 1≤q≤3, more preferably 2 or 3. r is preferably an integer satisfying 0≤r≤2.

In the general formulae (3-1) and (3-2), ^XBI is an iodine atom or a bromine atom, and when q is 2 or more, they may be the same as or different from each other.

In the general formulae (3-1) and (3-2), L ¹¹ is a single bond, an ether bond, an ester bond, or a saturated alkylene group having 1 to 6 carbon atoms which may contain an ether bond or an ester bond. The saturated alkylene group may be linear, branched, or cyclic.

In the general formulae (3-1) and (3-2), ^L12 is a single bond or a divalent linking group having 1 to 20 carbon atoms when r is 1, and is a trivalent or tetravalent linking group having 1 to 20 carbon atoms when r is 2 or 3. The linking group may contain an oxygen atom, a sulfur atom or a nitrogen atom.

In the general formulae (3-1) and (3-2), R ⁴⁰¹ is a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a saturated hydrocarbon group having 1 to 20 carbon atoms, a saturated hydrocarbon oxy group having 1 to 20 carbon atoms, a saturated hydrocarbon oxycarbonyl group having 2 to 10 carbon atoms, a saturated hydrocarbon carbonyloxy group having 2 to 20 carbon atoms or a saturated hydrocarbon sulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group or an ether bond, or -NR ^401A -C(=O)-R ^401B or -NR ^401A -C(=O)-OR ^401B . ^{R 401A} is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms or a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms. R ^401B is an aliphatic hydrocarbon group having 1 to 16 carbon atoms or an aryl group having 6 to 12 carbon atoms, and may contain a halogen atom, a hydroxyl group, a saturated hydrocarbon oxy group having 1 to 6 carbon atoms, a saturated hydrocarbon carbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbon carbonyloxy group having 2 to 6 carbon atoms. The aforementioned aliphatic hydrocarbon group may be saturated or unsaturated, and may be any of linear, branched, and cyclic. The aforementioned saturated hydrocarbon group, saturated hydrocarbon oxy group, saturated hydrocarbon oxycarbonyl group, saturated hydrocarbon carbonyl group, and saturated hydrocarbon carbonyloxy group may be any of linear, branched, and cyclic. When p and/or r is 2 or more, each R ⁴⁰¹ may be the same or different from each other.

Among them, R ⁴⁰¹ is preferably a hydroxyl group, -NR ^401A -C(=O)-R ^401B , -NR ^401A -C(=O)-OR ^401B , a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group or the like.

In general formulae (3-1) and (3-2), ^Rf11 to ^Rf14 are independently hydrogen atoms, fluorine atoms or trifluoromethyl groups, but at least one of them is a fluorine atom or a trifluoromethyl group. ^Rf11 and ^Rf12 may also be combined to form a carbonyl group. It is particularly preferred that both ^Rf13 and ^Rf14 are fluorine atoms.

In the general formulae (3-1) and (3-2), ^R402 , ^R403 , ^R404 , ^R405 and ^R406 are each independently a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, or a hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include the same examples as those exemplified as the hydrocarbon groups represented by ^R101 to ^R105 in the description of the general formulae (1-1) and (1-2). In addition, part or all of the hydrogen atoms of these groups may be substituted with a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone group, a sulfone group or a group containing a sulfonium salt, and part of the carbon atoms of these groups may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate group or a sulfonate bond. In this case ^, the ring may be the same as ^those exemplified as the ring that can be formed when ^R101 and ^R102 are bonded together with the sulfur atom to which they are bonded in the description of the general formula (1-1).

Examples of the cation of the sulfonium salt represented by the general formula (3-1) include the same examples as those exemplified as the cation of the sulfonium salt represented by the general formula (1-1). Examples of the cation of the iodonium salt represented by the general formula (3-2) include the same examples as those exemplified as the cation of the iodonium salt represented by the general formula (1-2).

Examples of the anion of the onium salt represented by the general formula (3-1) or (3-2) include, but are not limited to, the following. In the following formula, ^XBI is the same as described above.

[Chemistry 105]

[Chemistry 106]

[Chemistry 107]

[Chemistry 108]

[Chemistry 109]

[Chemistry 110]

[Chemistry 111]

[Chemistry 112]

[Chemistry 113]

[Chemistry 114]

[Chemistry 115]

[Chemistry 116]

[Chemistry 117]

[Chemistry 118]

[Chemistry 119]

[Chemistry 120]

[Chemistry 121]

[Chemistry 122]

[Chemistry 123]

[Chemistry 124]

[Chemistry 125]

[Chemistry 126]

[Chemistry 127]

In the resist composition of the present invention, the content of the additive acid generator is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, relative to 100 parts by mass of the resist material. The resist material contains repeating units d1 to d3 and/or contains an additive acid generator, whereby the resist composition of the present invention can function as a chemically amplified resist composition.

[Organic solvents]

An organic solvent may also be blended into the resist composition of the present invention. The aforementioned organic solvent is not particularly limited as long as it can dissolve the aforementioned components and the components described below. Such organic solvents include: ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone described in paragraphs [0144] to [0145] of Japanese Patent Publication No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; propylene glycol monomethyl ether, ethylene glycol Ethers such as monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as γ-butyrolactone; and mixed solvents thereof.

In the resist composition of the present invention, the content of the organic solvent is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass, based on 100 parts by mass of the resist material.

[Other ingredients]

In addition to the aforementioned components, a surfactant, a dissolution inhibitor, etc. are appropriately combined and blended according to the purpose to form a resist composition, whereby the aforementioned resist material will accelerate its dissolution rate in the developer due to the catalyst reaction in the exposure portion, so that a highly sensitive resist composition can be made. At this time, the resist film has high dissolution contrast and resolution, has exposure latitude, excellent process adaptability, and a good pattern shape after exposure. In particular, acid diffusion can be suppressed, so the density difference is small. Considering these characteristics, it can be made into a highly practical resist material that is very effective as a very large integrated circuit.

The surfactants described in paragraphs [0165] to [0166] of Japanese Patent Application Publication No. 2008-111103 can be cited. By adding a surfactant, the coating properties of the resist composition can be further improved or controlled. The surfactants can be used alone or in combination of two or more. In the resist composition of the present invention, the content of the surfactant is preferably 0.0001 to 10 parts by mass relative to 100 parts by mass of the resist material.

By adding a dissolution inhibitor, the difference in dissolution rate between the exposed area and the unexposed area can be further increased, and the resolution can be further improved.

The dissolution inhibitor preferably has a molecular weight of 100 to 1,000, more preferably 150 to 800, and includes compounds containing two or more phenolic hydroxyl groups in the molecule, wherein the hydrogen atoms of the phenolic hydroxyl groups are replaced by acid-labile groups at a ratio of 0 to 100 mol % as a whole, or compounds containing carboxyl groups in the molecule, wherein the hydrogen atoms of the carboxyl groups are replaced by acid-labile groups at an average ratio of 50 to 100 mol % as a whole. Specifically, compounds in which the hydrogen atoms of the hydroxyl groups and carboxyl groups of bisphenol A, trisphenol, phenolphthalein, cresol novolac resin, naphthalenecarboxylic acid, adamantanecarboxylic acid, and bile acid are replaced by acid-labile groups, etc., such as those described in paragraphs [0155] to [0178] of Japanese Patent Application Laid-Open No. 2008-122932.

The content of the dissolution inhibitor is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass, based on 100 parts by mass of the resist material. The dissolution inhibitor may be used alone or in combination of two or more.

The resist composition of the present invention may also be blended with a quencher (hereinafter referred to as other quenchers). Examples of the aforementioned other quenchers include known basic compounds. Examples of known basic compounds include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having carboxyl groups, nitrogen-containing compounds having sulfonyl groups, nitrogen-containing compounds having hydroxyl groups, nitrogen-containing compounds having hydroxyphenyl groups, alcoholic nitrogen-containing compounds, amides, imides, and carbamates. In particular, the primary, secondary, and tertiary amine compounds described in paragraphs [0146] to [0164] of Japanese Patent Publication No. 2008-111103 are preferred, and amine compounds having hydroxyl groups, ether bonds, ester bonds, lactone rings, cyano groups, and sulfonate bonds, or compounds having carbamate groups described in Japanese Patent Publication No. 3790649 are particularly preferred. By adding such a basic compound, for example, the diffusion rate of the acid in the resist film can be further suppressed or the shape can be corrected.

In addition, other quenchers include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids and carboxylic acids that are not fluorinated at the α-position as described in Japanese Patent Application Laid-Open No. 2008-158339. Sulfonic acids, imidic acids, or methide acids that are fluorinated at the α-position are necessary for deprotecting the acid-labile group of carboxylic acid esters, and the sulfonic acids or carboxylic acids that are not fluorinated at the α-position are released by salt exchange with the onium salts that are not fluorinated at the α-position. Sulfonic acids and carboxylic acids that are not fluorinated at the α-position do not cause deprotection reactions, and thus function as quenchers.

Other quenchers include polymer quenchers described in Japanese Patent Application Publication No. 2008-239918. The polymer quenchers are aligned on the resist surface after coating to improve the rectangularity of the resist after patterning. The polymer quenchers also have the effect of preventing film loss and doming of the pattern when using a protective film for immersion exposure.

In the resist composition of the present invention, the content of other quenchers is preferably 0 to 5 parts by mass, more preferably 0 to 4 parts by mass, based on 100 parts by mass of the resist material. Other quenchers may be used alone or in combination of two or more.

The resist composition of the present invention may also be mixed with a water repellency improver for improving the water repellency of the resist surface after spin coating. The aforementioned water repellency improver can be used in immersion lithography without using a top coat. The aforementioned water repellency improver is preferably a polymer compound containing a fluorinated alkyl group, a polymer compound containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue of a specific structure, and the like, and is preferably exemplified by Japanese Patent Publication No. 2007-297590 and Japanese Patent Publication No. 2008-111103. The aforementioned water repellency improver needs to be dissolved in an organic solvent developer. The aforementioned specific water repellency improver having a 1,1,1,3,3,3-hexafluoro-2-propanol residue has good solubility in a developer. As for the water repellency improver, a polymer compound containing a repeating unit containing an amino group or an amine salt has a high effect of preventing the evaporation of the acid during post-exposure baking (PEB) and preventing poor opening of the hole pattern after development. The water repellency improver may be used alone or in combination of two or more. In the resist composition of the present invention, the content of the water repellency improver is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, based on 100 parts by mass of the resist material.

The resist composition of the present invention may also contain acetylene alcohols. Examples of the acetylene alcohols include those described in paragraphs [0179] to [0182] of Japanese Patent Application Laid-Open No. 2008-122932. In the resist composition of the present invention, the content of the acetylene alcohols is preferably 0 to 5 parts by mass relative to 100 parts by mass of the resist material.

[Pattern Formation Method]

When the resist composition of the present invention is used in the manufacture of various integrated circuits, known photolithography techniques can be applied. That is, the present invention provides a pattern forming method comprising the following steps:

Using the resist composition described above to form a resist film on a substrate,

exposing the resist film to high energy radiation, and

The exposed resist film is developed using a developer.

For example, the resist composition of the present invention is applied to a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, _TiN , WSi, BPSG, SOG, organic antireflection film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, _MoSi2 , _SiO2 , etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, or blade coating so that the coating thickness becomes 0.01 to 2 μm. This is pre-baked on a hot plate preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 80 to 120°C for 30 seconds to 20 minutes, to form a resist film.

Then, the resist film is exposed using high-energy rays. Examples of the high-energy rays include ultraviolet rays, far ultraviolet rays, EB (electron beam), EUV (extreme ultraviolet rays), X-rays, soft X-rays, excimer lasers, i-rays, gamma rays, synchrotron radiation, and the like. Among them, i-rays, KrF excimer lasers, ArF excimer lasers, electron beams, or extreme ultraviolet rays with a wavelength of 3 to 15 nm are preferably used. When ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer lasers, gamma rays, synchrotron radiation, and the like are used as the high-energy rays, a mask for forming the intended pattern is used, and irradiation is performed in a manner where the exposure amount is preferably about 1 to 200 mJ/cm ² and more preferably about 10 to 100 mJ/cm ^2. When EB is used as the high-energy ray, the exposure amount is preferably about 0.1 to 100 μC/cm ² and more preferably about 0.5 to 50 μC/cm ^2, and the pattern is depicted directly or using a mask for forming the intended pattern. In addition, the resist composition of the present invention is particularly suitable for fine patterning using KrF excimer laser, ArF excimer laser, EB, EUV, X-ray, soft X-ray, γ-ray, and synchrotron radiation among high-energy rays, and is particularly suitable for fine patterning using EB or EUV.

After the exposure, PEB may be performed on a hot plate preferably at 50 to 150° C. for 10 seconds to 30 minutes, more preferably at 60 to 120° C. for 30 seconds to 20 minutes.

After exposure or PEB, a developer of an alkaline aqueous solution of 0.1 to 10 mass % and preferably 2 to 5 mass % tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH) or the like is used, and development is performed for 3 seconds to 3 minutes and preferably 5 seconds to 2 minutes using a common method such as a dip method, a puddle method, or a spray method, whereby the portion irradiated with light is dissolved in the developer, while the portion not exposed is not dissolved, and a desired positive pattern is formed on the substrate.

It is also possible to implement negative development of a negative pattern using a resist composition containing a resist material containing an acid-labile group and developing with an organic solvent. The developer used in this case may include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, amyl acetate, butyl acetate, isoamyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl crotonate, crotonyl acetate, propyl formate, butyl formate, isobutyl formate, amyl formate, isoamyl formate, methyl valerate, methyl pentenoate, methyl croton ... ethyl acetate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents may be used alone or in combination of two or more.

When the development is finished, rinsing may be performed. The rinsing solution is preferably a solvent that is miscible with the developer and does not dissolve the resist film. Such a solvent may preferably be an alcohol having 3 to 10 carbon atoms, an ether compound having 8 to 12 carbon atoms, an alkane, alkene, or alkyne having 6 to 12 carbon atoms, or an aromatic solvent.

Specifically, examples of the alcohol having 3 to 10 carbon atoms include n-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentanol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, and 1-octanol.

Examples of the ether compound having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di(sec-butyl) ether, di-n-pentyl ether, diisopentyl ether, di(sec-pentyl) ether, di(tert-pentyl) ether, and di-n-hexyl ether.

Examples of the alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, and cyclononane. Examples of the alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, and cyclooctene. Examples of the alkynes having 6 to 12 carbon atoms include hexyne, heptyne, and octyne.

Examples of the aromatic solvent include toluene, xylene, ethylbenzene, cumene, tert-butylbenzene, and mesitylene.

By performing rinsing, the occurrence of resist pattern collapse and defects can be reduced. In addition, rinsing is not essential, and the amount of solvent used can be reduced by not performing rinsing.

The hole pattern and groove pattern after development can also be shrunk by heat flow, RELACS technology or DSA technology. A shrinking agent is coated on the hole pattern, and the diffusion of the acid catalyst from the resist layer during baking will cause the shrinking agent to crosslink on the surface of the resist, and the shrinking agent will adhere to the side wall of the hole pattern. The baking temperature is preferably 70-180°C, preferably 80-170°C, and the time is preferably 10-300 seconds to remove the excess shrinking agent and shrink the hole pattern.

Example

Hereinafter, the present invention will be specifically described with reference to synthesis examples, examples and comparative examples, but the present invention is not limited to the following examples.

[1]Synthesis of monomers

[Synthesis Example]

[Synthesis Example 1-1] Synthesis of Monomer 1

Monomer 1 was synthesized according to the following scheme.

(1) Synthesis of Compound 2

Compound 1 (580 g), 2-chloroethanol (520 g), potassium carbonate (726 g), sodium bromide (31.5 g), and DMF (3,970 g) were mixed and stirred at 90°C for 20 hours. After the reaction was completed, it was ice-cooled, pure water (3,600 g) was added, and it was stirred for 30 minutes. Methyl isobutyl ketone (4,500 g) was then added and stirred for 1 hour. After the organic layer was separated and extracted, a usual aqueous work-up was performed, the solvent was distilled off, hexane (3,500 g) was added, and it was stirred for 2 hours and crystallized, and then filtered to obtain compound 2 (604 g) in the form of a solid.

The ¹ H-NMR (500 MHz, DMSO-d ₆ ) spectrum of Compound 2 is shown in FIG1 .

[Chemistry 128]

(2) Synthesis of Compound 3

Compound 2 (600 g) and tetrahydrofuran (2,800 g) were stirred under ice cooling, and 25% sodium hydroxide aqueous solution (330 g) and pure water (900 g) were added dropwise. The mixture was stirred at 40°C for 16 hours. After the reaction was completed, the organic solvent was distilled off and the aqueous solution was washed with TBME. 20% hydrochloric acid (430 g) and hexane (1 L) were added and stirred for crystallization and then filtered to obtain compound 3 (560 g) as a solid.

The ¹ H-NMR (500 MHz, DMSO-d ₆ ) spectrum of compound 3 is shown in FIG2 .

[Chemistry 129]

(3) Synthesis of Compound 4

Compound 3 (560 g), methacrylic anhydride (340 g), acetonitrile (3,000 g), and a polymerization inhibitor (1,000 ppm/theoretical yield) were dissolved, and a mixture of triethylamine (442 g), DMAP (22 g), and acetonitrile (600 g) was added dropwise under ice-cooling, and then stirred for 3 hours under ice-cooling. After the reaction was completed, 5% sodium bicarbonate water (1,900 g) was added under ice-cooling, and after stirring for 20 minutes, 20% hydrochloric acid aqueous solution (1,070 g) and pure water (5,300 g) were added and stirred for crystallization. The obtained solid was dissolved in ethyl acetate (4,500 g) by fractionation, and the organic layer was separated and extracted, and then washed with saturated brine and pure water, and the organic layer was treated with activated carbon. The solvent was distilled off, hexane (5.7 L) was added, and the mixture was stirred for crystallization and filtered to obtain compound 4 (460 g) as a solid.

The ¹ H-NMR (500 MHz, DMSO-d ₆ ) spectrum of compound 4 is shown in FIG3 .

[Chemistry 130]

(4) Synthesis of Monomer 1

Potassium carbonate (17 g), 1-pentanol (40 g), and pure water (90 g) were added to compound 4 (38 g) and stirred at room temperature for 1 hour, and then compound 5 (44 g) and dichloromethane (300 g) were added and stirred for 2 hours. After the organic layer was separated and extracted, a conventional aqueous work-up was performed, a polymerization inhibitor (100 ppm/theoretical yield) was added, and the solvent was distilled off to obtain monomer 1 (60 g) in an oily form. The obtained monomer 1 was dissolved in γ-butyrolactone (56 g) to prepare a γ-butyrolactone solution.

The ¹ H-NMR (500 MHz, DMSO-d ₆ ) spectrum of monomer 1 is shown in Figure 4. In addition to the peak of the target substance, peaks of the solvent used (1-pentanol, methyl isobutyl ketone, γ-butyrolactone) were also detected.

[Chemistry 131]

By ion exchange with a sulfonium salt bromide and an iodinated benzoic acid compound or a benzoic acid compound having a polymerizable double bond, the following monomers 2 to 15 and comparative monomers 1 to 3 were obtained. Monomer 1 is also shown together.

[Chemistry 132]

[Chemistry 133]

[Chemistry 134]

[Chemistry 135]

[2] Synthesis of polymers

The acid-labile group monomer (ALG monomer 1) and PAG monomers 1 to 8 used in the synthesis of the polymer are as follows. The Mw of the polymer was a polystyrene-equivalent measurement value obtained by GPC using THF as a solvent.

[Chemistry 136]

[Chemistry 137]

[Chemistry 138]

[Synthesis Example 2-1] Synthesis of Polymer 1

Monomer 1 (3.5 g), 1-methyl-1-cyclopentyl methacrylate (8.4 g), 4-hydroxystyrene (5.4 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing and nitrogen blowing under reduced pressure were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and it was reacted for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 1. The composition of polymer 1 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 139]

[Synthesis Example 2-2] Synthesis of Polymer 2

Monomer 2 (3.4 g), 1-methyl-1-cyclohexyl methacrylate (7.3 g), 4-hydroxystyrene (4.8 g), PAG monomer 2 (11.0 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing and nitrogen blowing under reduced pressure were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and it was reacted for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 2. The composition of polymer 2 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 140]

[Synthesis Example 2-3] Synthesis of Polymer 3

Monomer 3 (3.0 g), 1-methyl-1-cyclopentyl methacrylate (8.4 g), 4-hydroxystyrene (3.6 g), PAG monomer 1 (11.9 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and the reaction was allowed to proceed for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 3. The composition of polymer 3 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 141]

[Synthesis Example 2-4] Synthesis of Polymer 4

Monomer 4 (3.2 g), 1-methyl-1-cyclopentyl methacrylate (8.4 g), 3-hydroxystyrene (3.6 g), PAG monomer 2 (11.0 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and it was reacted for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 4. The composition of polymer 4 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 142]

[Synthesis Example 2-5] Synthesis of Polymer 5

Monomer 5 (4.1 g), 1-methyl-1-cyclopentyl methacrylate (8.4 g), 4-hydroxystyrene (4.2 g), PAG monomer 3 (8.5 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and the reaction was allowed to proceed for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 5. The composition of polymer 5 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 143]

[Synthesis Example 2-6] Synthesis of Polymer 6

Monomer 6 (4.9 g), ALG monomer 1 (8.9 g), 4-hydroxystyrene (5.4 g), PAG monomer 4 (10.2 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) as a polymerization initiator was added, the temperature was raised to 60 ° C, and it was reacted for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 6. The composition of polymer 6 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 144]

[Synthesis Example 2-7] Synthesis of Polymer 7

Monomer 7 (3.8 g), 1-methyl-1-cyclopentyl methacrylate (8.4 g), 4-hydroxystyrene (4.8 g), PAG monomer 5 (5.5 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and it was reacted for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 7. The composition of polymer 7 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 145]

[Synthesis Example 2-8] Synthesis of Polymer 8

Monomer 8 (3.4 g), ALG monomer 1 (8.9 g), 4-hydroxystyrene (5.4 g), PAG monomer 4 (9.7 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and it was reacted for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 8. The composition of polymer 8 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 146]

[Synthesis Example 2-9] Synthesis of Polymer 9

Monomer 1 (3.5 g), 1-methyl-1-cyclopentyl methacrylate (8.4 g), 4-hydroxystyrene (4.2 g), PAG monomer 6 (9.4 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and it was reacted for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 9. The composition of polymer 9 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 147]

[Synthesis Example 2-10] Synthesis of Polymer 10

Monomer 9 (3.8 g), 1-methyl-1-cyclopentyl methacrylate (8.4 g), 4-hydroxystyrene (4.2 g), PAG monomer 6 (9.4 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and the reaction was allowed to proceed for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 10. The composition of polymer 10 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 148]

[Synthesis Example 2-11] Synthesis of Polymer 11

Monomer 1 (3.5 g), 1-methyl-1-cyclopentyl methacrylate (8.4 g), 4-hydroxystyrene (4.2 g), PAG monomer 7 (9.6 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and it was reacted for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 11. The composition of polymer 11 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 149]

[Synthesis Example 2-12] Synthesis of Polymer 12

Monomer 9 (3.8 g), 1-methyl-1-cyclopentyl methacrylate (8.4 g), 4-hydroxystyrene (4.2 g), PAG monomer 7 (9.6 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and it was reacted for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 12. The composition of polymer 12 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 150]

[Synthesis Example 2-13] Synthesis of Polymer 13

Monomer 10 (3.8 g), 1-vinyl-1-cyclopentyl methacrylate (9.0 g), 3-hydroxystyrene (4.2 g), PAG monomer 6 (9.4 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing and nitrogen blowing under reduced pressure were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and the reaction was allowed to proceed for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 13. The composition of polymer 13 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 151]

[Synthesis Example 2-14] Synthesis of Polymer 14

Monomer 11 (4.5 g), 1-ethynyl-1-cyclopentyl methacrylate (8.9 g), 3-hydroxystyrene (4.2 g), PAG monomer 8 (9.8 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and it was reacted for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 14. The composition of polymer 14 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 152]

[Synthesis Example 2-15] Synthesis of Polymer 15

Monomer 12 (4.6 g), 1-ethynyl-1-cyclopentyl methacrylate (8.9 g), 3-hydroxystyrene (4.2 g), PAG monomer 8 (9.8 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and it was reacted for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 15. The composition of polymer 15 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 153]

[Synthesis Example 2-16] Synthesis of Polymer 16

Monomer 13 (4.2 g), ALG monomer 1 (8.9 g), 3-hydroxystyrene (4.2 g), PAG monomer 6 (9.4 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and it was reacted for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 16. The composition of polymer 16 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 154]

[Synthesis Example 2-17] Synthesis of Polymer 17

Monomer 14 (4.2 g), ALG monomer 1 (8.9 g), 3-hydroxystyrene (4.2 g), PAG monomer 6 (9.4 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) as a polymerization initiator was added, the temperature was raised to 60 ° C, and it was reacted for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 17. The composition of polymer 17 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 155]

[Synthesis Example 2-18] Synthesis of Polymer 18

Monomer 15 (4.7 g), ALG monomer 1 (8.9 g), 3-hydroxystyrene (4.2 g), PAG monomer 6 (9.4 g), and THF (40 g) as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 ° C under a nitrogen environment, and degassing under reduced pressure and nitrogen blowing were repeated 3 times. After warming to room temperature, AIBN (1.2 g) was added as a polymerization initiator, the temperature was raised to 60 ° C, and it was reacted for 15 hours. The reaction solution was added to 1 L of isopropanol, and the precipitated white solid was filtered. The obtained white solid was dried under reduced pressure at 60 ° C to obtain polymer 18. The composition of polymer 18 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 156]

[Comparative Synthesis Example 1] Synthesis of Comparative Polymer 1

A comparative polymer 1 was obtained in the same manner as in Synthesis Example 2-1 except that the monomer 1 was replaced with the comparative monomer 1. The composition of the comparative polymer 1 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 157]

[Comparative Synthesis Example 2] Synthesis of Comparative Polymer 2

Comparative polymer 2 was obtained in the same manner as in Synthesis Example 2-1 except that monomer 1 was replaced with comparative monomer 2. The composition of comparative polymer 2 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 158]

[Comparative Synthesis Example 3] Synthesis of Comparative Polymer 3

Comparative polymer 3 was obtained in the same manner as in Synthesis Example 2-1 except that monomer 1 was not used. The composition of comparative polymer 3 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 159]

[Comparative Synthesis Example 4] Synthesis of Comparative Polymer 4

Comparative polymer 4 was obtained in the same manner as in Synthesis Example 2-4 except that monomer 4 was not used. The composition of comparative polymer 4 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 160]

[Comparative Synthesis Example 5] Synthesis of Comparative Polymer 5

Comparative polymer 5 was obtained in the same manner as in Synthesis Example 2-1 except that monomer 1 was replaced with comparative monomer 3. The composition of comparative polymer 5 was confirmed by ¹³ C-NMR and ¹ H-NMR, and Mw and Mw/Mn were confirmed by GPC.

[Chemistry 161]

[Examples 1 to 22, Comparative Examples 1 to 5]

A solution prepared by dissolving the components shown in Tables 1 and 2 in an organic solvent in which 50 ppm of OMNOVA surfactant Polyfox 636 was dissolved was filtered through a 0.2 μm filter to obtain a resist composition.

In Tables 1 and 2, the components are as follows.

Organic solvent: PGMEA (propylene glycol monomethyl ether acetate)

DAA (Diacetone Alcohol)

EL(ethyl lactate)

Acid generator: PAG-1 (see the following structural formula)

Quencher: Q-1, Q-2, comparative quencher RQ-1 (see the following structural formula)

[Chemistry 162]

[EUV exposure evaluation]

Each resist composition shown in Tables 1 and 2 was spin-coated on a Si substrate with a silicon-containing spin-coated hard mask SHB-A940 (silicon content of 43 mass%) formed with a film thickness of 20 nm, and pre-baked at 105° C. for 60 seconds using a hot plate to obtain a resist film with a film thickness of 50 nm. It was exposed using an EUV scanning exposure machine NXE3400 manufactured by ASML (NA0.33, σ0.9/0.6, quadrupole illumination, a mask with a hole pattern with a size of 46 nm pitch on the wafer and a bias voltage of +20%), and PEB was performed for 60 seconds on a hot plate at the temperature described in Tables 1 and 2, and developed for 30 seconds with a 2.38 mass % TMAH aqueous solution to obtain a hole pattern with a size of 23 nm.

The exposure amount when the hole size was formed at 23 nm was measured and the result was defined as sensitivity. The size of 50 holes was measured using a length measurement SEM (CG6300) manufactured by Hitachi, Ltd. to determine CDU (dimensional variation 3σ).

The results are shown in Tables 1 and 2.

[Table 1]

[Table 2]

As can be seen from the results in Tables 1 and 2, the resist composition containing the resist material of the present invention using a specific polymer, wherein the specific polymer contains a repeating unit a having a sulfonium salt or iodonium salt structure of a monovalent aromatic carboxylic acid substituted with iodine, satisfies sufficient sensitivity and dimensional uniformity (Examples 1 to 22). In contrast, Comparative Examples 1 to 5 using the resist composition not containing the resist material of the present invention result in poor sensitivity and dimensional uniformity.

This specification includes the following aspects.

[1]: A resist material characterized by comprising a repeating unit a comprising a substituted or unsubstituted iodinated sulfonium salt or iodonium salt of a monovalent aromatic carboxylic acid bonded to a polymer main chain via an ester bond.

[2]: The resist material according to [1] above, wherein the repeating unit a comprises a repeating unit represented by the following general formula (a)-1 or (a)-2.

[Chemistry 163]

In the formula, ^RA is a hydrogen atom or a methyl group. ^X1' is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing an ester bond or an ether bond, and may also have one or more selected from a halogen atom, a hydroxyl group, an alkoxy group, an acyloxy group, a nitro group, and a cyano group. ^X2 is a single bond or a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms without a fluorine atom, and may also have one or more selected from an ether group and an ester group. Y is a group selected from an ester group and a sulfonate group. ^R1 is independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer of 1 to 4, and n is an integer of 0 to 3. R ² to R ⁶ are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a hetero atom. In addition, any two of R ² , R ³ and R ⁴ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

[3]: The resist material of [2] above is characterized in that: in the general formulas (a)-1 and (a)-2, the ^X2 is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom.

[4]: The resist material according to any one of [1] to [3], further comprising a repeating unit b in which the hydrogen atoms of one or both of a carboxyl group and a phenolic hydroxyl group are substituted with an acid-labile group.

[5]: The resist material according to [4] above, wherein the repeating unit b is at least one selected from the repeating units represented by the following general formulae (b1) and (b2).

[Chemistry 164]

In the formula, ^RA is independently a hydrogen atom or a methyl group. ^Y1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and having an ester bond, an ether bond, or a lactone ring. ^Y2 is a single bond, an ester bond, or an amide bond. ^R11 and ^R12 are acid-labile groups. ^R13 is a fluorine atom, a trifluoromethyl group, a cyano group, or an alkyl group having 1 to 6 carbon atoms. ^R14 is a single bond or a linear or branched alkanediyl group having 1 to 6 carbon atoms, and a portion of the carbon atoms thereof may be substituted by an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4.

[6]: The resist material according to any one of [1] to [5] above, characterized in that the resist material further contains a repeating unit c having an adhesive group selected from a hydroxyl group, a carboxyl group, a lactone ring, a carbonate group, a thiocarbonate group, a carbonyl group, a cyclic acetal group, an ether bond, an ester bond, a sulfonate bond, a cyano group, an amide group, -O-C(=O)-S-, and -O-C(=O)-NH-.

[7]: The resist material as described in any one of [1] to [6] above, characterized in that: the resist material further contains at least one repeating unit d selected from the repeating units represented by the following general formulas (d1) to (d3).

[Chemistry 165]

In the formula, ^RA is independently a hydrogen atom or a methyl group. ^Z1 is a single bond, a phenylene group, ^-OZ11- , -C(=O) ^-OZ11- or -C(=O)-NH- ^Z11- , ^Z11 is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms or a phenylene group, and may contain one or more selected from a carbonyl group, an ester bond, an ether bond, and a hydroxyl group. ^{Z2A is a single bond or an ester bond. Z2B is} a single bond or a divalent group having 1 to 12 carbon atoms, and may contain one or more selected from an ester bond, an ether bond, a lactone ring, a bromine atom, and an iodine atom. ^Z3 is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, ^-OZ31- , -C(=O) ^-OZ31- or -C(=O)-NH- ^Z31- , ^Z31 is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms or a phenylene group, and may contain one or more selected from a carbonyl group, an ester bond, an ether bond, a halogen atom, and a hydroxyl group. ^Rf1 to ^Rf4 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of them is a fluorine atom. ^R21 to ^R28 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom. In addition, any two of ^R23 , ^R24 and ^R25 or any two of ^R26 , ^R27 and ^R28 may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. ^M- is a non-nucleophilic counter ion.

[8]: The resist material according to [7] above, wherein the Z ^2B contains at least one iodine atom.

[9]: The resist material according to any one of [1] to [8] above, wherein the molecular weight of the resist material is in the range of 1,000 to 100,000.

[10]: A resist composition characterized by comprising a resist material as described in any one of [1] to [9] above.

[11]: The resist composition as described in [10] above is characterized in that it further contains one or more selected from the group consisting of an acid generator, an organic solvent, a quencher, and a surfactant.

[12]: A pattern forming method comprising the following steps:

Using the resist composition of [10] or [11] above, forming a resist film on a substrate,

exposing the resist film to high energy radiation, and

The exposed resist film is developed using a developer.

[13]: The pattern forming method as described in [12] above is characterized in that i-rays, KrF excimer lasers, ArF excimer lasers, electron beams, or extreme ultraviolet rays with a wavelength of 3 to 15 nm are used as the aforementioned high-energy rays.

[14]: A monomer characterized by being represented by the following general formula (a)-1M or (a)-2M.

[Chemistry 166]

In the formula, ^RA is a hydrogen atom or a methyl group. ^X1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing an ester bond or an ether bond, and may also contain a halogen atom. ^X2 is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms without a fluorine atom, and may also contain one or more selected from an ether group and an ester group. ^R1 is independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer of 1 to 4, and n is an integer of 0 to 3. ^R2 to ^R6 are independently a monovalent hydrocarbon group having 1 to 25 carbon atoms, which may also contain a heteroatom. Furthermore, any two of R ² , R ³ and R ⁴ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

[15]: A monomer characterized by being represented by the following general formula (a)-1’M or (a)-2’M.

[Chemistry 167]

In the formula, ^RA is a hydrogen atom or a methyl group. ^X1' is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms containing an ester bond or an ether bond, and may also have one or more selected from a halogen atom, a hydroxyl group, an alkoxy group, an acyloxy group, a nitro group, and a cyano group. ^X2 is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms without a fluorine atom, and may also have one or more selected from an ether group and an ester group. Y is a group selected from an ester group and a sulfonate group. ^R1 is independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. m is an integer of 1 to 4, and n is an integer of 0 to 3. R ² to R ⁶ are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a hetero atom. In addition, any two of R ² , R ³ and R ⁴ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

The present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and those having substantially the same configuration as the technical concept described in the claims of the present invention and having the same functions and effects are all included in the technical scope of the present invention.

Claims (15)

1. A resist material characterized by comprising a repeating unit a comprising a substituted or unsubstituted iodinated sulfonium salt or iodonium salt of a monovalent aromatic carboxylic acid bonded to a polymer main chain via an ester bond. 2. The resist material according to claim 1, wherein the repeating unit a comprises a repeating unit represented by the following general formula (a)-1 or (a)-2; In the formula, ^RA is a hydrogen atom or a methyl group; X1 ^' is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and containing an ester bond or an ether bond, and may also have one or more selected from a halogen atom, a hydroxyl group, an alkoxy group, an acyloxy group, a nitro group, and a cyano group; ^X2 is a single bond or a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom; ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms and not containing a fluorine atom, and may also have one or more selected from an ether group and an ester group; Y is a group selected from an ester group and a sulfonate group; ^{R1 is} each independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine; m is an integer of 1 to 4, and n is an integer of 0 to 3; ^R2 to R ⁶ are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a hetero atom; and any two of R ² , R ³ and R ⁴ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. 3. The resist material according to claim 2, wherein in the general formulas (a)-1 and (a)-2, ^X2 is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. 4 . The resist material according to claim 1 , further comprising a repeating unit b in which the hydrogen atoms of one or both of the carboxyl group and the phenolic hydroxyl group are substituted with an acid-labile group. 5. The resist material according to claim 4, wherein the repeating unit b is at least one selected from the repeating units represented by the following general formulae (b1) and (b2); In the formula, ^RA is independently a hydrogen atom or a methyl group; ^Y1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and having an ester bond, an ether bond, or a lactone ring; ^Y2 is a single bond, an ester bond, or an amide bond; ^R11 and ^R12 are acid-labile groups; ^R13 is a fluorine atom, a trifluoromethyl group, a cyano group, or an alkyl group having 1 to 6 carbon atoms; ^R14 is a single bond or a linear or branched alkanediyl group having 1 to 6 carbon atoms, and a portion of its carbon atoms may also be substituted by an ether bond or an ester bond; a is 1 or 2; and b is an integer from 0 to 4. 6. The resist material according to claim 1, wherein the resist material further comprises a repeating unit c having an adhesion group selected from the group consisting of a hydroxyl group, a carboxyl group, a lactone ring, a carbonate group, a thiocarbonate group, a carbonyl group, a cyclic acetal group, an ether bond, an ester bond, a sulfonate bond, a cyano group, an amide group, -O-C(=O)-S-, and -O-C(=O)-NH-. 7. The resist material according to claim 1, wherein the resist material further comprises at least one repeating unit d selected from the repeating units represented by the following general formulae (d1) to (d3); wherein ^RA is independently a hydrogen atom or a methyl group; ^Z1 is a single bond, a phenylene group, ^-OZ11- , -C(=O) ^-OZ11- , or -C(=O)-NH- ^Z11- ; ^Z11 is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms, or a phenylene group, and may contain at least one selected from a carbonyl group, an ester bond, an ether bond, and a hydroxyl group; ^Z2A is a single bond or an ester bond; ^Z2B is a single bond or a divalent group having 1 to 12 carbon atoms, and may contain at least one selected from an ester bond, an ether bond, a lactone ring, a bromine atom, and an iodine atom; ^Z3 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, ^-OZ31- , -C(=O) ^-OZ31- , or -C(=O)-NH- ^Z31- ; Z ^R21 to R28 are each independently a monovalent hydrocarbon group having ¹ to ²⁰ carbon atoms which may contain a heteroatom; any two of R23, R24 and R25 or any two ^{of R26} , ^{R27 and R28} may be bonded to each ^other and form a ring together with the sulfur atom to which they are bonded; and ^{M- is} a non- ^nucleophilic relative ion. 8 . The resist material according to claim 7 , wherein Z ^2B contains at least one iodine atom. 9 . The resist material according to claim 1 , wherein the molecular weight of the resist material is in the range of 1,000 to 100,000. 10. A resist composition, characterized by comprising the resist material according to any one of claims 1 to 9. 11. The resist composition according to claim 10, further comprising at least one selected from the group consisting of an acid generator, an organic solvent, a quencher, and a surfactant. 12. A pattern forming method comprising the following steps: forming a resist film on a substrate using the resist composition according to claim 10, exposing the resist film to high energy radiation, and The exposed resist film is developed using a developer. 13 . The pattern forming method according to claim 12 , wherein i-rays, KrF excimer lasers, ArF excimer lasers, electron beams, or extreme ultraviolet rays having a wavelength of 3 to 15 nm are used as the high-energy rays. 14. A monomer characterized by being represented by the following general formula (a)-1M or (a)-2M; In the formula, ^RA is a hydrogen atom or a methyl group; ^X1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and containing an ester bond or an ether bond, and may also contain a halogen atom; ^X2 is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom; ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms and not containing a fluorine atom, and may also contain one or more selected from an ether group and an ester group; ^R1 is ^each independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine; m is an integer of 1 to 4, and n is an integer of 0 to 3; ^R2 to R6 are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms and may contain a heteroatom; and ^R2 , ^R3, and R Any two of ⁴ may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. 15. A monomer characterized by being represented by the following general formula (a)-1'M or (a)-2'M; In the formula, ^RA is a hydrogen atom or a methyl group; X1 ^' is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and containing an ester bond or an ether bond, and may also have one or more selected from a halogen atom, a hydroxyl group, an alkoxy group, an acyloxy group, a nitro group, and a cyano group; ^X2 is a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, and may also contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom; ^X3 is a single bond or a linear or branched alkylene group having 1 to 6 carbon atoms and not containing a fluorine atom, and may also have one or more selected from an ether group and an ester group; Y is a group selected from an ester group and a sulfonate group; ^R1 is each independently a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine; m is an integer of 1 to 4, and n is an integer of 0 to 3; ^R2 to R ⁶ are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a hetero atom; and any two of R ² , R ³ and R ⁴ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.