Resist material and pattern forming method

Abstract

To provide a resist material having high sensitivity and small LWR and CDU irrespective of a positive type or a negative type, and a pattern formation method using the same.SOLUTION: A resist material containing a quencher containing a nitroxyl radical having an aromatic ring substituted with an iodine atom.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a resist material and a pattern forming method. [Background technology]

[0002] As LSIs become more highly integrated and faster, pattern rules are becoming finer at a rapid pace. In particular, the expansion of the logic memory market due to the spread of smartphones is driving miniaturization. The most advanced miniaturization technology is the mass production of 10nm node devices using double patterning with ArF immersion lithography, and preparations are underway for the mass production of 7nm node devices using double patterning for the next generation. Extreme ultraviolet (EUV) lithography is being considered as a candidate for the next-generation 5nm node.

[0003] While logic devices are becoming more miniaturized, flash memory devices have become devices with stacked gates called 3D-NAND, and the capacity is increasing as the number of layers increases. As the number of layers increases, the hard masks used to process them become thicker, and the photoresist film also becomes thicker. The resist film for logic devices is becoming thinner, while the resist film for 3D-NAND is becoming thicker.

[0004] As miniaturization progresses and approaches the diffraction limit of light, the contrast of light decreases. This decrease in contrast of light causes a decrease in the resolution of hole and trench patterns and a decrease in focus margin in positive resist films. Increasing the thickness of the resist film would restore the film thickness of the resist film for previous generation devices, but a higher degree of dimensional uniformity (CDU) is required, which cannot be met by previous photoresist films. In order to prevent a decrease in the resolution of the resist pattern due to the decrease in contrast of light caused by smaller dimensions, or to improve the CDU when thickening the resist film, attempts are being made to improve the dissolution contrast of the resist film.

[0005] For chemically amplified positive resist materials, which contain an acid generator and generate an acid by irradiation with light or an electron beam (EB) to cause a deprotection reaction by the acid, and for chemically amplified negative resist materials, which cause a polarity change reaction or a crosslinking reaction by the acid, the addition of a quencher to control the diffusion of the acid into unexposed areas and improve the contrast has been very effective. For this reason, many amine quenchers have been proposed (Patent Documents 1 and 2).

[0006] An amine quencher with a polarity change caused by an acid catalyst has been proposed. Patent Document 3 proposes an amine quencher with an acid labile group. This is a tertiary ester with a carbonyl group on the nitrogen atom side that generates a carboxylic acid by a deprotection reaction with an acid, improving the alkali solubility. However, in this case, the molecular weight on the nitrogen atom side cannot be increased, so the acid diffusion control ability is low and the effect of improving contrast is slight. Patent Document 4 proposes a quencher in which an amino group is generated by a deprotection reaction of a tert-butoxycarbonyl group with an acid. This is a mechanism in which a quencher is generated by exposure to light, which is the opposite effect to increasing contrast. The contrast is improved by a mechanism in which the quencher disappears or the quenching ability is reduced by exposure to light or an acid. Patent Document 5 proposes a quencher in which an amine compound forms a ring with an acid to form a lactam structure. The activity of the acid changes as a strong base amine compound changes to a weak base lactam compound, improving contrast.

[0007] The acid labile group used in the (meth)acrylate polymer for ArF resist material undergoes a deprotection reaction by using a photoacid generator that generates a sulfonic acid substituted with a fluorine atom at the α-position, but does not proceed with an acid generator that generates a sulfonic acid or carboxylic acid not substituted with a fluorine atom at the α-position. When a sulfonium salt or iodonium salt that generates a sulfonic acid not substituted with a fluorine atom at the α-position is mixed with a sulfonium salt or iodonium salt that generates a sulfonic acid not substituted with a fluorine atom at the α-position, the sulfonium salt or iodonium salt that generates a sulfonic acid not substituted with a fluorine atom at the α-position undergoes ion exchange with the sulfonic acid not substituted with a fluorine atom at the α-position. The sulfonic acid generated by light and substituted with a fluorine atom at the α-position reverts to a sulfonium salt or iodonium salt by ion exchange, so the sulfonium salt or iodonium salt of the sulfonic acid or carboxylic acid not substituted with a fluorine atom at the α-position functions as a quencher. A resist material has been proposed that uses a sulfonium salt or an iodonium salt that generates a carboxylic acid as a quencher (Patent Document 6).

[0008] The sulfonium salt type quencher and the iodonium salt type quencher are photodecomposable like the photoacid generator. That is, the amount of quencher is reduced in the exposed area. Since acid is generated in the exposed area, when the amount of quencher is reduced, the concentration of acid is relatively increased, which improves the contrast. However, since the acid diffusion in the exposed area cannot be suppressed, it becomes difficult to control the acid diffusion.

[0009] Since sulfonium salt type quenchers and iodonium salt type quenchers absorb light with a wavelength of 193 nm, when used in combination with a sulfonium salt type or iodonium salt type acid generator, the transmittance of the light through the resist film decreases. As a result, the cross-sectional shape of the pattern after development becomes tapered, particularly in resist films with a thickness of 100 nm or more. A highly transparent quencher is required for resist films with a thickness of 100 nm or more, particularly 150 nm or more.

[0010] Amine quenchers having aromatic groups substituted with iodine atoms have been proposed (Patent Document 7). Iodine atoms have high EUV absorption, so secondary electrons are generated by exposure, which has a sensitizing effect on the acid generator. Furthermore, because the atomic weight of iodine atoms is large, they have high acid diffusion control ability.

[0011] The decomposition of the acid generator occurs not only due to the generation of secondary electrons during exposure, but also due to the generation of radicals. In this case, it is important to suppress the diffusion of the radicals. However, the amine quencher cannot suppress the diffusion of the radicals generated during exposure, and the basicity does not change due to exposure, so there is a problem that the contrast improvement effect like that of the photodecomposition type quencher cannot be expected. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] JP 2001-194776 A [Patent Document 2] JP 2007-108451 A [Patent Document 3] JP 2002-363148 A [Patent Document 4] JP 2001-166476 A [Patent Document 5] JP 2012-137729 A [Patent Document 6] International Publication No. 2008 / 066011 [Patent Document 7] JP 2020-27297 A Summary of the Invention [Problem to be solved by the invention]

[0013] In chemically amplified resist materials using acid as a catalyst, it is desirable to develop a quencher that can reduce the line edge roughness (LWR) of line patterns and the CDU of hole patterns while also improving sensitivity. To achieve this, it is necessary to further reduce image blurring caused by acid diffusion.

[0014] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a resist material which has high sensitivity and small LWR and CDU, whether positive or negative, and a pattern formation method using the same. [Means for solving the problem]

[0015] Means for Solving the Problems The present inventors have conducted extensive research in order to achieve the above-mentioned object, and as a result have found that a nitroxyl radical having an aromatic ring substituted with an iodine atom (hereinafter also referred to as an iodized aromatic ring-containing nitroxyl radical) can suppress not only acid diffusion but also the diffusion of radicals generated during exposure, and that by using this as a quencher, it is possible to obtain a resist material which has small LWR and CDU, high contrast, excellent resolution, and a wide process margin, and have thus completed the present invention.

[0016] That is, the present invention provides the following resist material and pattern forming method. 1. A resist material comprising a quencher that includes a nitroxyl radical having an aromatic ring substituted with an iodine atom. 2. The resist material of 1, wherein the nitroxyl radical is represented by any one of the following formulas (A-1) to (A-3). [ka] (In the formula, m 1 is 1, 2 or 3. 2 is 1 or 2. n 1 and n 2 is 1≦n 1 ≦5, 0≦n 2 ≦4 and 1≦n 1 +n 2n is an integer that satisfies ≦5. 3 , n 4 and n 5 is 1≦n 3 ≦4, 2≦n 4 ≦4, 0≦n 5 ≦3 and 3≦n 3 +n 4 +n 5 It is an integer satisfying the condition ≦6. X 1 , X 2A and X 2B are each independently a single bond, an ester bond, an ether bond, or an amide bond. R 1 is a hydroxy group, a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an amino group, -N(R 1A )-C(=O)-R 1B , -N(R 1A )-C(=O)-OR 1B Or -N(R 1A )-S(=O)2-R 1B R 1A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 1B represents a saturated hydrocarbyl group having 1 to 6 carbon atoms, an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms, which may be substituted with a halogen atom. R 2 is a hydrocarbyl group having 1 to 20 carbon atoms, which may contain at least one selected from a hydroxy group, a carboxy group, a thioether bond, an ether bond, an ester bond, a nitro group, a cyano group, a sulfonyl group, a halogen atom, and an amino group, provided that it does not contain a phenyl group substituted with an iodine atom. R 3A m 1 When m is 1, it is a single bond or a hydrocarbylene group having 1 to 10 carbon atoms; 1 When is 2 or 3, (m 1 R is a 1)valent hydrocarbon group. 3BR is a single bond or a hydrocarbylene group having 1 to 10 carbon atoms. 3C is a hydrocarbylene group having 1 to 10 carbon atoms. 1 The monovalent hydrocarbon group may contain at least one selected from a hydroxy group, a carboxy group, a thiol group, an ether bond, an ester bond, a nitro group, a cyano group, a sulfonyl group, a sultone ring, a halogen atom, and an amino group. R 4A and R 4B R is a single bond or a hydrocarbylene group having 1 to 10 carbon atoms. 2 and R 4A or R 4B may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and in this case, the ring may contain a double bond, an oxygen atom, a sulfur atom or a nitrogen atom. However, the nitroxyl radical represented by formula (A-1) does not include the nitroxyl radical represented by formula (A-3). 3. The resist material according to 1 or 2, further comprising an acid generator that generates acid. 4. The resist material of any one of 1 to 3, wherein the acid generator generates a sulfonic acid, an imide acid or a methide acid. 5. A resist material according to any one of 1 to 4, further comprising an organic solvent. 6. A resist material according to any one of 1 to 5, further comprising a base polymer. 7. The resist material according to 6, wherein the base polymer contains a repeating unit represented by the following formula (a1) or a repeating unit represented by the following formula (a2): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. Y 1 is a linking group having 1 to 12 carbon atoms and containing at least one selected from a single bond, a phenylene group, a naphthylene group, an ester bond, or a lactone ring. Y 2 is a single bond or an ester bond. Y3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are each independently an acid labile group. R 13 is a fluorine atom, a trifluoromethyl group, a cyano group or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 14 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of the carbon atoms of which may be substituted with ether bonds or ester bonds. a is 1 or 2, and b is an integer from 0 to 4, provided that 1≦a+b≦5. 8. The resist material of 7, which is a chemically amplified positive resist material. 9. The resist material of 6, wherein the base polymer does not contain an acid labile group. 10. The resist material of 9, which is a chemically amplified negative resist material. 11. A resist material according to any one of 1 to 10, further comprising a surfactant. 12. The resist material of any one of 6 to 11, wherein the base polymer further contains a repeating unit represented by any one of the following formulas (f1) to (f3): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. Z 1 represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these groups, or -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -It is. 11 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group obtained by combining these and having 7 to 18 carbon atoms, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 2is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -OC(=O)-. Z 31 represents a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group obtained by combining these and having 7 to 18 carbon atoms, and may contain a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine atom. Z 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. Z 5 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -OZ 51 -, -C(=O)-OZ 51 - or -C(=O)-NH-Z 51 -It is. 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. R 21 ~R 28 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 23 and R 24 and R 26 and R 27 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. M - is a non-nucleophilic counterion. 13. A pattern forming method comprising the steps of forming a resist film on a substrate using a resist material according to any one of claims 1 to 12, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer. 14. The pattern formation method according to 13, wherein the high-energy radiation is i-rays having a wavelength of 365 nm, ArF excimer laser light having a wavelength of 193 nm, or KrF excimer laser light having a wavelength of 248 nm. 15. The pattern formation method according to claim 13, wherein the high energy radiation is EB or EUV having a wavelength of 3 to 15 nm. Effect of the Invention

[0017] The iodized aromatic ring-containing nitroxyl radical is a quencher that suppresses acid diffusion, and at the same time, it reacts with radicals generated during exposure to ionize, so it also has the effect of suppressing the diffusion of radicals generated during exposure. This results in low acid diffusion properties, making it possible to reduce LWR and CDU. This makes it possible to construct a resist material with improved LWR and CDU. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] [Resist material] The resist material of the present invention contains a quencher that includes an iodized aromatic ring-containing nitroxyl radical.

[0019] [Iodinated aromatic ring-containing nitroxyl radicals] The iodized aromatic ring-containing nitroxyl radical is preferably one represented by any one of the following formulae (A-1) to (A-3): The nitroxyl radical represented by formula (A-1) does not include the nitroxyl radical represented by formula (A-3). [ka]

[0020] In formulas (A-1) to (A-3), m 1 is 1, 2 or 3. 2 is 1 or 2. 1 and n 2 is 1≦n 1 ≦5, 0≦n 2 ≦4 and 1≦n 1 +n 2n is an integer that satisfies ≦5. 3 , n 4 and n 5 is 1≦n 3 ≦4, 2≦n 4 ≦4, 0≦n 5 ≦3 and 3≦n 3 +n 4 +n 5 It is an integer satisfying the condition ≦6.

[0021] In formulas (A-1) to (A-3), X 1 , X 2A and X 2B are each independently a single bond, an ester bond, an ether bond, or an amide bond.

[0022] In formulas (A-1) to (A-3), R 1 is a hydroxy group, a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an amino group, -N(R 1A )-C(=O)-R 1B , -N(R 1A )-C(=O)-OR 1B Or -N(R 1A )-S(=O)2-R 1B R 1A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 1B represents a saturated hydrocarbyl group having 1 to 6 carbon atoms, an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms, which may be substituted with a halogen atom.

[0023] R 1 , R 1A and R 1BThe saturated hydrocarbyl group having 1 to 6 carbon atoms represented by the formula (I) may be linear, branched or cyclic, and specific examples thereof include alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl and n-hexyl groups; and cyclic saturated hydrocarbyl groups having 3 to 6 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl groups. 1 Examples of the saturated hydrocarbyl moiety of the saturated hydrocarbyloxy group having 1 to 6 carbon atoms represented by the formula (I) include the same as the specific examples of the saturated hydrocarbyl group described above, and R 1 Examples of the saturated hydrocarbyl moiety of the saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms represented by the following formula include those having 1 to 5 carbon atoms among the specific examples of the saturated hydrocarbyl groups mentioned above.

[0024] In formulas (A-1) to (A-3), R 2is a hydrocarbyl group having 1 to 20 carbon atoms. The hydrocarbyl group having 1 to 20 carbon atoms may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, or an icosyl group; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, or an adamantyl group; alkenyl groups having 2 to 20 carbon atoms, such as a vinyl group, a propenyl group, a butenyl group, or a hexenyl group; and a cyclohexenyl group and a norbornenyl group. alkynyl groups having 2 to 20 carbon atoms, such as ethynyl, propynyl, and butynyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, and tert-butylnaphthyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl and phenethyl; and groups obtained by combining these, such as 2-cyclohexylethynyl and 2-phenylethynyl. The hydrocarbyl group may contain at least one selected from a hydroxy group, a carboxy group, a thioether bond, an ether bond, an ester bond, a nitro group, a cyano group, a sulfonyl group, a halogen atom, and an amino group. 2 does not include a phenyl group substituted with an iodine atom.

[0025] In formulas (A-1) to (A-3), R 3A m 1When m is 1, it is a single bond or a hydrocarbylene group having 1 to 10 carbon atoms; 1 When is 2 or 3, (m 1 R is a 1)valent hydrocarbon group. 3B R is a single bond or a hydrocarbylene group having 1 to 10 carbon atoms. 3C is a hydrocarbylene group having 1 to 10 carbon atoms. 1 The monovalent hydrocarbon group may contain at least one selected from a hydroxy group, a carboxy group, a thiol group, an ether bond, an ester bond, a nitro group, a cyano group, a sulfonyl group, a sultone ring, a halogen atom, and an amino group.

[0026] In formulas (A-1) to (A-3), R 4A and R 4B R is a single bond or a hydrocarbylene group having 1 to 10 carbon atoms. 2 and R 4A or R 4B may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and in this case, the ring may contain a double bond, an oxygen atom, a sulfur atom or a nitrogen atom.

[0027] R 3A , R 3B , R 3C , R 4A and R 4BThe hydrocarbylene group having 1 to 10 carbon atoms represented by the formula (1) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,2-diyl group, a propane-1,3-diyl group, a propane-2,2-diyl group, a butane-1,2-diyl group, a butane-1,3-diyl group, a butane-1,4-diyl group, a butane-2,2-diyl group, a butane-2,3-diyl group, a 2-methylpropane-1,3-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1, alkanediyl groups having 1 to 10 carbon atoms, such as 8-diyl group, nonane-1,9-diyl group, and decane-1,10-diyl group; cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms, such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, and adamantanediyl group; unsaturated aliphatic hydrocarbylene groups having 2 to 10 carbon atoms, such as vinylene group and propene-1,3-diyl group; arylene groups having 6 to 10 carbon atoms, such as phenylene group and naphthylene group; and groups obtained by combining these. 3A The carbon number is 1 to 10 (m 1 The monovalent hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include groups obtained by further removing one or two hydrogen atoms from the specific examples of the hydrocarbylene groups having 1 to 10 carbon atoms described above.

[0028] R 2 and R 4A and R 2 and R 4B When and are bonded to each other to form a ring together with the nitrogen atom to which they are bonded, the ring is preferably one represented by any one of the following formulas (A-4) to (A-6). [ka]

[0029] In formulas (A-4) to (A-6), the dashed lines represent X 2A Or X 2B It is a bond with R. 5 ~R8 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 5 and R 6 and / or R 7 and R 8 and may be bonded to each other to form a ring together with the carbon atoms to which they are attached, R 5 and R 7 and may be bonded to each other to form a ring together with the carbon atom to which they are bonded and the nitrogen atom contained therebetween. In this case, the ring formed by bonding these substituents to each other may contain an oxygen atom, a sulfur atom, or a nitrogen atom therein.

[0030] R 5 ~R 8 The saturated hydrocarbyl group having 1 to 6 carbon atoms represented by the formula (I) may be linear, branched, or cyclic. Specific examples thereof include R 1 , R 1A and R 1B Among these, the same as those exemplified as the saturated hydrocarbyl group having 1 to 6 carbon atoms represented by R 5 ~R 8 is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, further preferably a hydrogen atom, a methyl group or an ethyl group, and most preferably a methyl group.

[0031] Examples of the iodized aromatic ring-containing nitroxyl radical include, but are not limited to, those shown below. [ka]

[0032] [ka]

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[0053] The iodized aromatic ring-containing nitroxyl radical can be synthesized, for example, by an esterification reaction between a carboxylic acid having an aromatic ring substituted with an iodine atom and a nitroxyl radical having a hydroxy group.

[0054] The iodized aromatic ring-containing nitroxyl radical can suppress the diffusion of radicals generated during EB or EUV exposure, thereby suppressing blurring of images in the resist film. The iodized aromatic ring-containing nitroxyl radical can also suppress the diffusion of acids, so that the LWR and CDU of the resist pattern after development can be improved by suppressing both acid diffusion and radical diffusion.

[0055] After the iodized aromatic ring-containing nitroxyl radical absorbs the radical, the oxygen atom is negatively charged, and the acid neutralizing ability of the adjacent nitrogen atom is reduced. The acid trapping ability of the exposed area is reduced, thereby improving the contrast.

[0056] In the resist material of the present invention, the content of the iodized aromatic ring-containing nitroxyl radical is preferably 0.001 to 50 parts by mass, more preferably 0.01 to 40 parts by mass, based on 100 parts by mass of a base polymer described below, from the viewpoint of the effect of suppressing the diffusion of radicals and acids. The iodized aromatic ring-containing nitroxyl radical may be used alone or in combination of two or more kinds.

[0057] [Base polymer] In the case of a positive resist material, the base polymer contained in the resist material of the present invention contains a repeating unit containing an acid labile group. The repeating unit containing an acid labile group is preferably a repeating unit represented by the following formula (a1) (hereinafter also referred to as repeating unit a1) or a repeating unit represented by the following formula (a2) (hereinafter also referred to as repeating unit a2). [ka]

[0058] In formulas (a1) and (a2), R A Each of Y is independently a hydrogen atom or a methyl group. 1 Y is a linking group having 1 to 12 carbon atoms and containing at least one selected from a single bond, a phenylene group, a naphthylene group, an ester bond, and a lactone ring. 2is a single bond or an ester bond. 3 R is a single bond, an ether bond or an ester bond. 11 and R 12 are each independently an acid labile group. When the base polymer contains both the repeating unit a1 and the repeating unit a2, R 11 and R 12 may be the same or different. 13 R is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of the carbon atoms of which may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4, with the proviso that 1≦a+b≦5.

[0059] Examples of monomers that provide the repeating unit a1 include, but are not limited to, those shown below. A and R 11 is the same as above. [ka]

[0060] Examples of monomers that provide the repeating unit a2 include, but are not limited to, those shown below. A and R 12 is the same as above. [ka]

[0061] In formulas (a1) and (a2), R 11 and R 12 Examples of the acid labile group represented by the formula (I) include those described in JP-A-2013-80033 and JP-A-2013-83821.

[0062] Typically, the acid labile group includes those represented by the following formulae (AL-1) to (AL-3). [ka] (In the formula, the dashed lines represent bonds.)

[0063] In formulas (AL-1) and (AL-2), R L1 and R L2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group is preferably a saturated hydrocarbyl group having 1 to 40 carbon atoms, more preferably a saturated hydrocarbyl group having 1 to 20 carbon atoms.

[0064] In formula (AL-1), c is an integer of 0 to 10, and an integer of 1 to 5 is preferable.

[0065] In formula (AL-2), R L3 and R L4 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group is preferably a saturated hydrocarbyl group having 1 to 20 carbon atoms. L2 , R L3 and R L4 Any two of these may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom or the carbon atom and oxygen atom to which they are bonded. As the ring, a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.

[0066] In formula (AL-3), R L5 , R L6 and R L7are each independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group is preferably a saturated hydrocarbyl group having 1 to 20 carbon atoms. L5 , R L6 and R L7 Any two of these may be bonded to each other to form, together with the carbon atom to which they are bonded, a ring having 3 to 20 carbon atoms. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0067] The base polymer may contain a repeating unit b containing a phenolic hydroxy group as an adhesive group. Examples of monomers that provide the repeating unit b include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

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[0070] The base polymer may contain a repeating unit c containing a hydroxy group other than a phenolic hydroxy group, a lactone ring, a sultone ring, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonyl group, a sulfonyl group, a cyano group, or a carboxy group as another adhesive group. Examples of monomers that provide the repeating unit c include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

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[0081] The base polymer may include repeat units d derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene, or derivatives thereof. Monomers that provide repeat units d include, but are not limited to, those shown below. [ka]

[0082] The base polymer may include repeat units e derived from styrene, vinyl naphthalene, vinyl anthracene, vinyl pyrene, methylene indane, vinyl pyridine, or vinyl carbazole.

[0083] The base polymer may contain a repeating unit f derived from an onium salt containing a polymerizable unsaturated bond. Preferred repeating units f include a repeating unit represented by the following formula (f1) (hereinafter also referred to as repeating unit f1), a repeating unit represented by the following formula (f2) (hereinafter also referred to as repeating unit f2), and a repeating unit represented by the following formula (f3) (hereinafter also referred to as repeating unit f3). The repeating units f1 to f3 may be used alone or in combination of two or more. [ka]

[0084] In formulas (f1) to (f3), R A are each independently a hydrogen atom or a methyl group. 1 represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these groups, or -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -It is. 11Z is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these groups, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 2 is a single bond or an ester bond. 3 is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -OC(=O)-. Z 31 Z is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine atom. 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. 5 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -OZ 51 -, -C(=O)-OZ 51 - or -C(=O)-NH-Z 51 -It is. 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group.

[0085] In formulas (f1) to (f3), R 21 ~R 28 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 101 ~R 105Examples of the hydrocarbyl group include the same as those exemplified in the description of the above. The hydrocarbyl group may have some or all of its hydrogen atoms substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the carbon atoms of these groups may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like. 23 and R 24 or R 26 and R 27 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring is as defined in the description of formula (1-1) below, 101 and R 102 and the sulfur atom to which they are bonded to form a ring, the same as those exemplified above.

[0086] In formula (f1), M - is a non-nucleophilic counter ion. Examples of the non-nucleophilic counter ion include halide ions such as chloride ion and bromide ion; fluoroalkylsulfonate ions such as triflate ion, 1,1,1-trifluoroethanesulfonate ion, and nonafluorobutanesulfonate ion; arylsulfonate ions such as tosylate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion, and 1,2,3,4,5-pentafluorobenzenesulfonate ion; alkylsulfonate ions such as mesylate ion and butanesulfonate ion; imide ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion, and bis(perfluorobutylsulfonyl)imide ion; and methide ions such as tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0087] Other examples of the non-nucleophilic counter ion include a sulfonate ion represented by the following formula (f1-1) in which the α-position is substituted with a fluorine atom, and a sulfonate ion represented by the following formula (f1-2) in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group. [ka]

[0088] In formula (f1-1), R 31 is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain an ether bond, an ester bond, a carbonyl group, a lactone ring, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A'). 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those described below.

[0089] In formula (f1-2), R 32 is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbylcarbonyl group having 2 to 30 carbon atoms, and the hydrocarbyl group and the hydrocarbylcarbonyl group may contain an ether bond, an ester bond, a carbonyl group, or a lactone ring. The hydrocarbyl moiety of the hydrocarbyl group and the hydrocarbylcarbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R in formula (1A'). 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those described below.

[0090] Examples of the cation of the monomer that gives the repeating unit f1 include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0091] Examples of the cation of the monomer that gives the repeating unit f2 or f3 include the same as those exemplified as the cation of the sulfonium salt represented by formula (1-1) described later.

[0092] Examples of the anion of the monomer that gives the repeating unit f2 include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0093] [ka]

[0094] [ka]

[0095] [ka]

[0096] [ka]

[0097] [ka]

[0098] [ka]

[0099] [ka]

[0100] [ka]

[0101] [ka]

[0102] [ka]

[0103] [ka]

[0104] Examples of the anion of the monomer that gives the repeating unit f3 include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0105] By binding the acid generator to the polymer main chain, acid diffusion is reduced, and a decrease in resolution due to blurring caused by acid diffusion can be prevented. Furthermore, the LWR and CDU are improved by uniformly dispersing the acid generator. When a base polymer containing the repeating unit f (i.e., a polymer-bound acid generator) is used, the incorporation of an additive acid generator, which will be described later, can be omitted.

[0106] The base polymer for the positive resist material essentially contains a repeating unit a1 or a2 containing an acid-labile group. In this case, the content ratios of the repeating units a1, a2, b, c, d, e, and f are preferably 0 ≦ a1 < 1.0, 0 ≦ a2 < 1.0, 0 < a1 + a2 < 1.0, 0 ≦ b ≦ 0.9, 0 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.8, 0 ≦ e ≦ 0.8, and 0 ≦ f ≦ 0.5, more preferably 0 ≦ a1 ≦ 0.9, 0 ≦ a2 ≦ 0.9, 0.1 ≦ a1 + a2 ≦ 0.9, 0 ≦ b ≦ 0.8, 0 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.7, 0 ≦ e ≦ 0.7, and 0 ≦ f ≦ 0.4, and even more preferably 0 ≦ a1 ≦ 0.8, 0 ≦ a2 ≦ 0.8, 0.1 ≦ a1 + a2 ≦ 0.8, 0 ≦ b ≦ 0.75, 0 ≦ c ≦ 0.75, 0 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.6, and 0 ≦ f ≦ 0.3. When the repeating unit f is at least one selected from the repeating units f1 to f3, f = f1 + f2 + f3. Also, a1 + a2 + b + c + d + e + f = 1.0.

[0107] On the other hand, the base polymer for the negative resist material does not necessarily require an acid-labile group. Examples of such a base polymer include those containing the repeating unit b and optionally further containing the repeating units c, d, e, and / or f. The content ratios of these repeating units are preferably 0 < b ≦ 1.0, 0 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.8, 0 ≦ e ≦ 0.8, and 0 ≦ f ≦ 0.5, more preferably 0.2 ≦ b ≦ 1.0, 0 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.7, 0 ≦ e ≦ 0.7, and 0 ≦ f ≦ 0.4, and even more preferably 0.3 ≦ b ≦ 1.0, 0 ≦ c ≦ 0.75, 0 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.6, and 0 ≦ f ≦ 0.3. When the repeating unit f is at least one selected from the repeating units f1 to f3, f = f1 + f2 + f3. Also, b + c + d + e + f = 1.0.

[0108] To synthesize the base polymer, for example, monomers that provide the above-described repeating units may be heated in an organic solvent with the addition of a radical polymerization initiator to perform polymerization.

[0109] Examples of the organic solvent used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, and dioxane. Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The temperature during polymerization is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, and more preferably 5 to 20 hours.

[0110] When a monomer containing a hydroxy group is copolymerized, the hydroxy group may be substituted with an acetal group that is easily deprotected by an acid, such as an ethoxyethoxy group, during polymerization, and then deprotected with a weak acid and water after polymerization; alternatively, the hydroxy group may be substituted with an acetyl group, a formyl group, a pivaloyl group, or the like, and then subjected to alkaline hydrolysis after polymerization.

[0111] When hydroxystyrene or hydroxyvinylnaphthalene is copolymerized, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and after polymerization, the acetoxy group may be deprotected by the above-mentioned alkaline hydrolysis to give hydroxystyrene or hydroxyvinylnaphthalene.

[0112] As the base for the alkaline hydrolysis, ammonia water, triethylamine, etc. can be used. 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.

[0113] The base polymer has a weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC) using THF as a solvent of preferably 1,000 to 500,000, more preferably 2,000 to 30,000. When the Mw is within the above range, the resist film has good heat resistance and solubility in an alkaline developer.

[0114] In addition, when the base polymer has a wide molecular weight distribution (Mw / Mn), low and high molecular weight polymers are present, which may result in foreign matter being found on the pattern after exposure or deterioration of the pattern shape. As the pattern rule becomes finer, the effects of Mw and Mw / Mn tend to become greater, so in order to obtain a resist material suitable for fine pattern dimensions, it is preferable that the Mw / Mn of the base polymer has a narrow distribution of 1.0 to 2.0, particularly 1.0 to 1.5.

[0115] The base polymer may include two or more polymers having different composition ratios, Mw, and Mw / Mn.

[0116] [Acid generator] The resist material of the present invention may contain an acid generator (hereinafter also referred to as an additive acid generator) that generates a strong acid. The strong acid here means a compound having sufficient acidity to cause a deprotection reaction of an acid labile group of a base polymer in the case of a chemically amplified positive resist material, and means a compound having sufficient acidity to cause a polarity change reaction or a crosslinking reaction by an acid in the case of a chemically amplified negative resist material. By including such an acid generator, the iodized aromatic ring-containing nitroxyl radical functions as a quencher, and the resist material of the present invention can function as a chemically amplified positive resist material or a chemically amplified negative resist material.

[0117] The acid generator may be, for example, a compound (photoacid generator) that generates an acid in response to actinic rays or radiation. The photoacid generator may be any compound that generates an acid when irradiated with high-energy rays, but is preferably one that generates a sulfonic acid, an imide acid, or a methide acid. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate-type acid generators. Specific examples of photoacid generators include those described in paragraphs

[0122] to

[0142] of JP2008-111103A.

[0118] In addition, as the photoacid generator, a sulfonium salt represented by the following formula (1-1) or an iodonium salt represented by the following formula (1-2) can also be suitably used. [ka]

[0119] In formulas (1-1) and (1-2), R 101 ~R 105 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom.

[0120] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0121] R 101 ~R 105The hydrocarbyl group having 1 to 20 carbon atoms represented by the following formula may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples of such alkyl groups include alkyl groups having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, or an icosyl group; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, or an adamantyl group; alkenyl groups having 2 to 20 carbon atoms, such as a vinyl group, a propenyl group, a butenyl group, or a hexenyl group; and an ethynyl group. alkynyl groups having 2 to 20 carbon atoms, such as a propynyl group or a butynyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexenyl group or a norbornenyl group; aryl groups having 6 to 20 carbon atoms, such as a phenyl group, a methylphenyl group, an ethylphenyl group, a n-propylphenyl group, an isopropylphenyl group, a n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, a n-propylnaphthyl group, an isopropylnaphthyl group, a n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group or a tert-butylnaphthyl group; aralkyl groups having 7 to 20 carbon atoms, such as a benzyl group or a phenethyl group; and groups obtained by combining these.

[0122] In addition, some or all of the hydrogen atoms of these groups may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the carbon atoms of these groups may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, these groups may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like.

[0123] Also, R 101 and R 102 and may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring is preferably one having the structure shown below. [ka] (In the formula, the dashed line represents R 103 It is a bond with .)

[0124] Examples of the cation of the sulfonium salt represented by formula (1-1) include, but are not limited to, those shown below. [ka]

[0125] [ka]

[0126] [ka]

[0127] [ka]

[0128] [ka]

[0129]

change

[0130]

change

[0131]

change

[0132]

change

[0133]

change

[0134]

change

[0135]

change

[0136]

change

[0137]

change

[0138]

change

[0139] [ka]

[0140] [ka]

[0141] Examples of the cation of the iodonium salt represented by formula (1-2) include, but are not limited to, those shown below. [ka]

[0142] [ka]

[0143] In formulas (1-1) and (1-2), Xa - is an anion selected from the following formulas (1A) to (1D). [ka]

[0144] In formula (1A), R fa is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0145] The anion represented by formula (1A) is preferably one represented by the following formula (1A'). [ka]

[0146] In formula (1A'), R HFR is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 111 is a hydrocarbyl group having 1 to 38 carbon atoms which may contain a heteroatom. The heteroatom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc., and more preferably an oxygen atom. In order to obtain high resolution in the formation of a fine pattern, the hydrocarbyl group is preferably one having 6 to 30 carbon atoms.

[0147] R 111 The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 38 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, a 2-ethylhexyl group, a nonyl group, an undecyl group, a tridecyl group, a pentadecyl group, a heptadecyl group, and an icosanyl group; a cyclopentyl group, a cyclohexyl group, a 1-adamantyl group, a 2-adamantyl group, a 1-adamantylmethyl group, a norbornyl group, Examples of the alkyl group include cyclic saturated hydrocarbyl groups having 3 to 38 carbon atoms, such as a norbornylmethyl group, a tricyclodecanyl group, a tetracyclododecanyl group, a tetracyclododecanylmethyl group, and a dicyclohexylmethyl group; unsaturated aliphatic hydrocarbyl groups having 2 to 38 carbon atoms, such as an allyl group and a 3-cyclohexenyl group; aryl groups having 6 to 38 carbon atoms, such as a phenyl group, a 1-naphthyl group, and a 2-naphthyl group; aralkyl groups having 7 to 38 carbon atoms, such as a benzyl group and a diphenylmethyl group; and groups obtained by combining these groups.

[0148] In addition, some or all of the hydrogen atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, resulting in the group containing a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. Examples of hydrocarbyl groups containing heteroatoms include a tetrahydrofuryl group, a methoxymethyl group, an ethoxymethyl group, a methylthiomethyl group, an acetamidomethyl group, a trifluoroethyl group, a (2-methoxyethoxy)methyl group, an acetoxymethyl group, a 2-carboxy-1-cyclohexyl group, a 2-oxopropyl group, a 4-oxo-1-adamantyl group, and a 3-oxocyclohexyl group.

[0149] Synthesis of sulfonium salts containing an anion represented by formula (1A') is described in detail in JP-A-2007-145797, JP-A-2008-106045, JP-A-2009-7327, JP-A-2009-258695, etc. In addition, sulfonium salts described in JP-A-2010-215608, JP-A-2012-41320, JP-A-2012-106986, JP-A-2012-153644, etc. are also preferably used.

[0150] Examples of the anion represented by formula (1A) include, but are not limited to, those shown below: In the following formula, Ac is an acetyl group. [ka]

[0151] [ka]

[0152] [ka]

[0153] [ka]

[0154] In formula (1B), R fb1 and R fb2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by the formula R include the same as those exemplified above. fb1 and R fb2 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 and R fb2 means that the groups (-CF2-SO2-N - -SO2-CF2-) may form a ring, in which case, R fb1 and R fb2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0155] In formula (1C), R fc1 , R fc2 and R fc3 are each independently a hydrocarbyl group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by the formula R include the same as those exemplified above. fc1 , R fc2 and R fc3 is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 and R fc2 means that the groups (-CF2-SO2-C- -SO2-CF2-) may form a ring, in which case, R fc1 and R fc2 The group obtained by bonding together is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0156] In formula (1D), R fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above.

[0157] The synthesis of a sulfonium salt containing an anion represented by formula (1D) is described in detail in JP-A-2010-215608 and JP-A-2014-133723.

[0158] Examples of the anion represented by formula (1D) include, but are not limited to, those shown below. [ka]

[0159] [ka]

[0160] Although the photoacid generator containing the anion represented by formula (1D) does not have a fluorine atom at the α-position of the sulfo group, it has two trifluoromethyl groups at the β-position, and therefore has sufficient acidity to cleave the acid labile group in the base polymer, and can therefore be used as a photoacid generator.

[0161] As the photoacid generator, a compound represented by the following formula (2) can also be suitably used. [ka]

[0162] In formula (2), R 201 and R 202 R are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. 203 is a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. 201 , R 202 and R 203 Any two of may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring may be any of the groups represented by R 101 and R 102 and the sulfur atom to which they are bonded to form a ring, the same as those exemplified above.

[0163] R 201 and R 202 The hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms, 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 groups; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl and tricyclo[5.2.1.0]. 2,6cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as a decanyl group, and an adamantyl group; aryl groups having 6 to 30 carbon atoms, such as a phenyl group, a methylphenyl group, an ethylphenyl group, an n-propylphenyl group, an isopropylphenyl group, an n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, an n-propylnaphthyl group, an isopropylnaphthyl group, an n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group, a tert-butylnaphthyl group, and an anthracenyl group; and groups obtained by combining these groups. In addition, some or all of the hydrogen atoms of these groups may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the carbon atoms of these groups may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, these groups may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, or the like.

[0164] R 203The hydrocarbylene group represented by the formula (I) may be saturated or unsaturated and may be linear, branched or cyclic. Specific examples thereof include alkanediyl groups having 1 to 30 carbon atoms, such as a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group, a dodecane-1,12-diyl group, a tridecane-1,13-diyl group, a tetradecane-1,14-diyl group, a pentadecane-1,15-diyl group, a hexadecane-1,16-diyl group, and a heptadecane-1,17-diyl group; a cyclopentanediyl group, a cyclohexanediyl group, and the like. Examples of the alkylene groups include cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms, such as axanediyl group, norbornanediyl group, and adamantanediyl group; arylene groups having 6 to 30 carbon atoms, such as a phenylene group, a methylphenylene group, an ethylphenylene group, an n-propylphenylene group, an isopropylphenylene group, an n-butylphenylene group, an isobutylphenylene group, a sec-butylphenylene group, a tert-butylphenylene group, a naphthylene group, a methylnaphthylene group, an ethylnaphthylene group, an n-propylnaphthylene group, an isopropylnaphthylene group, an n-butylnaphthylene group, an isobutylnaphthylene group, a sec-butylnaphthylene group, and a tert-butylnaphthylene group; and groups obtained by combining these groups. In addition, some or all of the hydrogen atoms of these groups may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the carbon atoms of these groups may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, so that the group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. The heteroatom is preferably an oxygen atom.

[0165] In formula (2), L Ais a hydrocarbylene group having 1 to 20 carbon atoms which may contain a single bond, an ether bond, or a heteroatom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 203 Examples of the hydrocarbylene group represented by the following formula include the same as those exemplified above.

[0166] In formula (2), X A , X B , X C and X D are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. A , X B , X C and X D At least one of the groups is a fluorine atom or a trifluoromethyl group.

[0167] In formula (2), k is an integer of 0 to 3.

[0168] The photoacid generator represented by formula (2) is preferably one represented by the following formula (2'). [ka]

[0169] In formula (2'), L A is the same as above. R HF R is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 301 , R 302 and R 303 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 111 Examples of the hydrocarbyl group represented by the formula: x and y each independently represent an integer of 0 to 5, and z represents an integer of 0 to 4.

[0170] Examples of the photoacid generator represented by formula (2) include the same as those exemplified as the photoacid generator represented by formula (2) in JP2017-026980A.

[0171] Among the photoacid generators, those containing an anion represented by formula (1A') or (1D) are particularly preferred because of their small acid diffusion and excellent solubility in solvents, while those represented by formula (2') are particularly preferred because of their extremely small acid diffusion.

[0172] The photoacid generator may be a sulfonium salt or an iodonium salt containing an anion having an aromatic ring substituted with an iodine atom or a bromine atom. Examples of such salts include those represented by the following formula (3-1) or (3-2). [ka]

[0173] In formulas (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.

[0174] In formulas (3-1) and (3-2), X BI is an iodine atom or a bromine atom, and when p and / or q is 2 or more, they may be the same or different.

[0175] In formulas (3-1) and (3-2), L 1 is a single bond, an ether bond or an ester bond, or a saturated hydrocarbylene group having 1 to 6 carbon atoms which may contain an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched or cyclic.

[0176] In formulas (3-1) and (3-2), L 2represents a single bond or a divalent linking group having 1 to 20 carbon atoms when p is 1, and represents a (p+1)-valent linking group having 1 to 20 carbon atoms when p is 2 or 3, and the linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0177] In formulas (3-1) and (3-2), R 401 is a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom, or an amino group, or a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 20 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 10 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, or a saturated hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group, or an ether bond, or 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D Or -N(R 401C )-C(=O)-OR 401D R 401A and R 401B R are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 401C R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. 401Dis an aliphatic hydrocarbyl group having 1 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. The aliphatic hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbyloxycarbonyl group, saturated hydrocarbylcarbonyl group, and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. When p and / or r is 2 or more, each R 401 may be the same or different from each other.

[0178] Of these, R 401 Examples of the hydroxyl group include -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-OR 401D , a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group, and the like are preferred.

[0179] In formulas (3-1) and (3-2), Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, at least one of which is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine to form a carbonyl group. 3 and Rf 4 are preferably both fluorine atoms.

[0180] In formulas (3-1) and (3-2), R 402 ~R 406are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 101 ~R 105 Examples of the hydrocarbyl group represented by the formula (I) include the same as those exemplified above. In addition, some or all of the hydrogen atoms of these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone group, a sulfone group, or a sulfonium salt-containing group, and some 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 bond, or a sulfonate ester bond. 402 and R 403 and may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring is as defined in the description of formula (1-1) as R 101 and R 102 and , when bonded to each other, can form a ring together with the sulfur atom to which they are bonded, similar to those exemplified above.

[0181] Examples of the cation of the sulfonium salt represented by formula (3-1) include the same as those exemplified as the cation of the sulfonium salt represented by formula (1-1). Examples of the cation of the iodonium salt represented by formula (3-2) include the same as those exemplified as the cation of the iodonium salt represented by formula (1-2).

[0182] Examples of the anion of the onium salt represented by formula (3-1) or (3-2) include, but are not limited to, those shown below. In the following formula, X BI is the same as above. [ka]

[0183] [ka]

[0184]

change

[0185]

change

[0186]

change

[0187]

change

[0188]

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[0189]

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[0190]

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[0191]

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[0192]

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[0193]

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[0194]

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[0195]

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[0196]

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[0197]

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[0198]

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[0199]

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[0200]

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[0201]

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[0202]

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[0203]

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[0204]

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[0205] When the resist material of the present invention contains an additive acid generator, the content thereof is preferably 0.1 to 50 parts by mass, and more preferably 1 to 40 parts by mass, relative to 100 parts by mass of the base polymer. Since the base polymer contains the repeating unit f and / or the resist material contains an additive acid generator, the resist material of the present invention can function as a chemically amplified resist material.

[0206] [Organic solvents] The resist material of the present invention may contain an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the above-mentioned components and the components described below. Examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] to

[0145] of JP-A-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 monomethyl ether, propylene glycol monoethyl ether, and ethylene glycol Examples of the monoethyl ether include ethers such as propylene 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 mono-tert-butyl ether acetate; and lactones such as γ-butyrolactone.

[0207] In the resist material 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 base polymer. The organic solvent may be used alone or in combination of two or more kinds.

[0208] [Other ingredients] In addition to the above-mentioned components, surfactants, dissolution inhibitors, crosslinking agents, quenchers other than the iodized aromatic ring-containing nitroxyl radical (hereinafter referred to as other quenchers), etc. can be appropriately combined and blended according to the purpose to form a positive resist material or a negative resist material, whereby the dissolution rate of the base polymer in the developer is accelerated by a catalytic reaction in the exposed area, so that a positive resist material or a negative resist material with extremely high sensitivity can be obtained. In this case, the dissolution contrast and resolution of the resist film are high, there is exposure margin, and the process adaptability is excellent, and the pattern shape after exposure is good, while the dimensional difference between the coarse and fine areas is small, in particular because acid diffusion can be suppressed, and therefore the resist material is highly practical and can be very effective as a resist material for VLSI.

[0209] Examples of the surfactant include those described in paragraphs

[0165] to

[0166] of JP 2008-111103 A. The addition of a surfactant can further improve or control the coatability of the resist material. When the resist material of the present invention contains the surfactant, the content thereof is preferably 0.0001 to 10 parts by mass relative to 100 parts by mass of the base polymer. The surfactant may be used alone or in combination of two or more kinds.

[0210] When the resist material of the present invention is a positive type, the difference in dissolution rate between the exposed and unexposed areas can be further increased by adding a dissolution inhibitor, and the resolution can be further improved. The dissolution inhibitor includes a compound having a molecular weight of preferably 100 to 1,000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups in the molecule, in which the hydrogen atoms of the phenolic hydroxyl groups are substituted with acid labile groups at a ratio of 0 to 100 mol % as a whole, or a compound containing a carboxyl group in the molecule, in which the hydrogen atoms of the carboxyl groups are substituted with acid labile groups at an average ratio of 50 to 100 mol % as a whole. Specific examples include bisphenol A, trisphenol, phenolphthalein, cresol novolac, naphthalene carboxylic acid, adamantane carboxylic acid, hydroxyl groups of cholic acid, and compounds in which hydrogen atoms of carboxyl groups are substituted with acid labile groups, and the like, and are described, for example, in paragraphs

[0155] to

[0178] of JP-A-2008-122932.

[0211] When the resist material of the present invention is a positive type and contains the dissolution inhibitor, the content thereof is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass, based on 100 parts by mass of the base polymer. The dissolution inhibitor may be used alone or in combination of two or more kinds.

[0212] On the other hand, when the resist material of the present invention is a negative type, a crosslinking agent can be added to reduce the dissolution rate of the exposed area to obtain a negative pattern. Examples of the crosslinking agent include epoxy compounds, melamine compounds, guanamine compounds, glycoluril compounds or urea compounds, isocyanate compounds, azide compounds, and compounds containing double bonds such as alkenyloxy groups, which are substituted with at least one group selected from methylol groups, alkoxymethyl groups, and acyloxymethyl groups. These may be used as additives, or may be introduced as pendant groups into the polymer side chain. Compounds containing hydroxyl groups may also be used as crosslinking agents.

[0213] Examples of the epoxy compound include tris(2,3-epoxypropyl)isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

[0214] Examples of the melamine compound include hexamethylol melamine, hexamethoxymethyl melamine, a compound in which 1 to 6 methylol groups of hexamethylol melamine are methoxymethylated or a mixture thereof, hexamethoxyethyl melamine, hexaacyloxymethyl melamine, a compound in which 1 to 6 methylol groups of hexamethylol melamine are acyloxymethylated or a mixture thereof, and the like.

[0215] Examples of the guanamine compound include tetramethylol guanamine, tetramethoxymethyl guanamine, a compound in which 1 to 4 methylol groups of tetramethylol guanamine are methoxymethylated or a mixture thereof, tetramethoxyethyl guanamine, tetraacyloxyguanamine, a compound in which 1 to 4 methylol groups of tetramethylol guanamine are acyloxymethylated or a mixture thereof, and the like.

[0216] Examples of glycoluril compounds include tetramethylol glycoluril, tetramethoxy glycoluril, tetramethoxymethyl glycoluril, compounds in which 1 to 4 methylol groups of tetramethylol glycoluril are methoxymethylated or mixtures thereof, compounds in which 1 to 4 methylol groups of tetramethylol glycoluril are acyloxymethylated or mixtures thereof, etc. Examples of urea compounds include tetramethylol urea, tetramethoxymethyl urea, compounds in which 1 to 4 methylol groups of tetramethylol urea are methoxymethylated or mixtures thereof, tetramethoxyethyl urea, etc.

[0217] Examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

[0218] Examples of the azide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0219] Examples of compounds containing an alkenyloxy group include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, and trimethylolpropane trivinyl ether.

[0220] When the resist composition of the present invention is a negative type and contains a crosslinking agent, the content thereof is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, based on 100 parts by mass of the base polymer. The crosslinking agent may be used alone or in combination of two or more kinds.

[0221] Examples of the other quenchers include conventional basic compounds. Examples of conventional basic compounds include primary, secondary, or tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxy group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, carbamates, and the like. In particular, the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonic acid ester bond, or compounds having a carbamate group described in JP Patent No. 3790649, are preferred. By adding such a basic compound, for example, it is possible to further suppress the diffusion rate of the acid in the resist film or correct the shape.

[0222] Other quenchers include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids and carboxylic acids not fluorinated at the α-position, as described in JP-A-2008-158339. Sulfonic acids, imide acids, or methide acids fluorinated at the α-position are necessary for deprotecting the acid labile group of a carboxylic acid ester, but the sulfonic acids or carboxylic acids not fluorinated at the α-position are released by salt exchange with onium salts not fluorinated at the α-position. Sulfonic acids and carboxylic acids not fluorinated at the α-position do not cause a deprotection reaction, and therefore function as quenchers.

[0223] Other examples of the quencher include the polymer-type quencher described in JP 2008-239918 A. This enhances the rectangularity of the resist pattern by orienting on the surface of the resist film. The polymer-type quencher also has the effect of preventing film loss of the pattern and rounding of the pattern top when a protective film for immersion exposure is applied.

[0224] When the resist composition of the present invention contains another quencher, the content thereof is preferably 0 to 5 parts by mass, more preferably 0 to 4 parts by mass, relative to 100 parts by mass of the base polymer. The other quenchers may be used alone or in combination of two or more kinds.

[0225] The resist material of the present invention may contain a water repellency improver to improve the water repellency of the resist film surface. The water repellency improver can be used in immersion lithography without using a topcoat. As the water repellency improver, a polymer containing a fluorinated alkyl group, a polymer containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue of a specific structure, and the like are preferred, and those exemplified in JP-A-2007-297590 and JP-A-2008-111103 are more preferred. The water repellency improver needs to be dissolved in an alkaline developer or an organic solvent developer. The water repellency improver having the specific 1,1,1,3,3,3-hexafluoro-2-propanol residue described above has good solubility in the developer. As a water repellency improver, a polymer containing a repeating unit containing an amino group or an amine salt is highly effective in preventing the evaporation of acid during post-exposure baking (PEB) and preventing poor opening of a hole pattern after development. When the resist composition of the present invention contains a water repellency improver, the content thereof 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 base polymer. The water repellency improver may be used alone or in combination of two or more kinds.

[0226] The resist material of the present invention may contain acetylene alcohols. Examples of the acetylene alcohols include those described in paragraphs

[0179] to

[0182] of JP 2008-122932 A. When the resist material of the present invention contains acetylene alcohols, the content thereof is preferably 0 to 5 parts by mass relative to 100 parts by mass of the base polymer. The acetylene alcohols may be used alone or in combination of two or more kinds.

[0227] [Pattern formation method] When the resist material of the present invention is used in various integrated circuit manufacturing, known lithography techniques can be applied.For example, as a pattern forming method, the method includes the steps of forming a resist film on a substrate using the above-mentioned resist material, exposing the resist film to high-energy radiation, and developing the exposed resist film using a developer.

[0228] First, the resist material of the present invention is applied to a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by a suitable coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., so that the coating thickness is 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.

[0229] Next, the resist film is exposed to high-energy radiation. Examples of the high-energy radiation include ultraviolet radiation, far ultraviolet radiation, EB, EUV radiation with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, gamma rays, synchrotron radiation, etc. When ultraviolet radiation, far ultraviolet radiation, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, synchrotron radiation, etc. are used as the high-energy radiation, the exposure dose is preferably 1 to 200 mJ / cm2, either directly or using a mask for forming a desired pattern. 2 Approximately, more preferably 10 to 100 mJ / cm 2 When EB is used as the high energy beam, the exposure dose is preferably 0.1 to 100 μC / cm 2 Approximately, more preferably 0.5 to 50 μC / cm 2The resist material of the present invention is suitable for fine patterning using high energy rays, particularly i-rays with a wavelength of 365 nm, KrF excimer laser light, ArF excimer laser light, EB, EUV, X-rays, soft X-rays, γ-rays, and synchrotron radiation, and is particularly suitable for fine patterning using EB or EUV.

[0230] After the exposure, PEB may or may not be performed on a hot plate or in an oven, preferably at 30 to 150° C. for 10 seconds to 30 minutes, more preferably at 50 to 120° C. for 30 seconds to 20 minutes.

[0231] After exposure or PEB, the exposed resist film is developed by a conventional method such as a dip method, a puddle method, or a spray method using a developer of an alkaline aqueous solution of 0.1 to 10 mass%, preferably 2 to 5 mass%, such as tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), or tetrabutylammonium hydroxide (TBAH) for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, to form a desired pattern. In the case of a positive resist material, the part irradiated with light dissolves in the developer, and the part not exposed does not dissolve, forming a positive pattern on the substrate. In the case of a negative resist material, the opposite is true from the case of a positive resist material, that is, the part irradiated with light becomes insoluble in the developer, and the part not exposed dissolves.

[0232] A negative pattern can also be obtained by organic solvent development using a positive resist material containing a base polymer containing an acid labile group. The developer used in this case is 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, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, Examples of the organic solvent include methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl 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 can be used alone or in combination of two or more.

[0233] At the end of the development, rinsing is performed. As the rinsing liquid, a solvent that is miscible with the developer and does not dissolve the resist film is preferable. As such a solvent, alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms are preferably used.

[0234] Specific examples of alcohols having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, and 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.

[0235] 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.

[0236] Examples of alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. Examples of alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Examples of alkynes having 6 to 12 carbon atoms include hexine, heptine, octyne, etc.

[0237] Examples of aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, and mesitylene.

[0238] Rinsing can reduce the occurrence of resist pattern collapse and defects. Rinsing is not always necessary, and not performing rinsing can reduce the amount of solvent used.

[0239] The developed hole pattern or trench pattern can also be shrunk by thermal flow, RELACS technology, or DSA technology. A shrink agent is applied onto the hole pattern, and the shrink agent crosslinks on the surface of the resist film due to the diffusion of an acid catalyst from the resist film during baking, and the shrink agent adheres to the sidewalls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds, and excess shrink agent is removed to reduce the hole pattern. EXAMPLES

[0240] The present invention will be specifically described below with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples.

[0241] The structures of quenchers Q-1 to Q-20 used in the resist material are shown below. Q-1 to Q-20 were synthesized by an esterification reaction between a carboxylic acid having an aromatic ring substituted with an iodine atom and a nitroxyl radical having a hydroxyl group, an esterification reaction between a carboxylic acid having an aromatic ring substituted with an iodine atom and a nitroxyl radical having a glycidyloxy group, and an esterification reaction between a phenol substituted with an iodine atom and a nitroxyl radical having a carboxy group. [ka]

[0242] [ka]

[0243] [ka]

[0244] [Synthesis Example] Synthesis of base polymers (polymers P-1 to P-4) Each monomer was combined and copolymerized in THF, a solvent. The reaction solution was poured into methanol, and the precipitated solid was repeatedly washed with hexane, isolated, and dried to obtain base polymers (P-1 to P-4) with the following compositions. The resulting base polymers had the following compositions: 1 Mw and Mw / Mn were confirmed by H-NMR and GPC (solvent: THF, standard: polystyrene). [ka]

[0245] [Examples 1 to 25, Comparative Examples 1 to 3] Preparation of resist materials and their evaluation (1) Preparation of resist material Resist materials were prepared by filtering solutions in which each component was dissolved according to the compositions shown in Tables 1 to 3 through a 0.2 μm filter. The resist materials of Examples 1 to 20, 22 to 25 and Comparative Examples 1 and 2 were positive-type, and the resist materials of Example 21 and Comparative Example 3 were negative-type.

[0246] In Tables 1 to 3, the components are as follows. Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (Diacetone Alcohol)

[0247] Acid generator: PAG-1~PAG-4 [ka]

[0248] Blend Quencher: bQ-1~bQ-3 [ka]

[0249] Comparison quenchers: cQ-1, cQ-2 [ka]

[0250] (2) EUV lithography evaluation Each resist material shown in Tables 1 to 3 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed to a thickness of 20 nm, and the resist film was pre-baked at 100°C for 60 seconds using a hot plate to produce a resist film with a thickness of 50 nm. This was exposed using an EUV scanner NXE3300 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, quadruple pole illumination, a hole pattern mask with a pitch of 44 nm on the wafer and a +20% bias), and PEB was performed on a hot plate at the temperatures shown in Tables 1 to 3 for 60 seconds, and development was performed with a 2.38% by mass TMAH aqueous solution for 30 seconds to obtain hole patterns with a size of 22 nm in Examples 1 to 20, 22 to 25 and Comparative Examples 1 and 2, and dot patterns with a size of 22 nm in Example 21 and Comparative Example 3. Using a critical dimension SEM (CG6300) manufactured by Hitachi High-Technologies Corporation, the exposure dose when a hole or dot dimension of 22 nm was formed was measured and used as the sensitivity, and the dimensions of 50 holes or dots were measured at this time, and the standard deviation (σ) calculated from the results was tripled (3σ) to use as the dimensional variation (CDU). The results are shown in Tables 1 to 3.

[0251] [Table 1]

[0252] [Table 2]

[0253] [Table 3]

[0254] The results shown in Tables 1 to 3 demonstrate that the resist material of the present invention, which contains a quencher that includes a nitroxyl radical having an aromatic ring substituted with an iodine atom, has high sensitivity and small CDU.

Claims

1. The resist material comprises a quencher containing a nitroxyl radical having an aromatic ring substituted with an iodine atom, a base polymer, and an acid generator that generates an acid.

2. A resist material comprising a quencher containing a nitroxyl radical having an aromatic ring substituted with an iodine atom, and a base polymer containing a repeating unit represented by any one of the following formulas (f1) to (f3): 【Chemistry 1】 (In the formula, each R A is independently a hydrogen atom or a methyl group. Z 1 is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or -O-Z 11 -, -C(═O)-O-Z 11 -, or -C(═O)-NH-Z 11 -. Z 11 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(═O)-O-, -Z 31 -O-, or -Z 31 -O-C(═O)-. Z 31 is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine atom. Z 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group or a carbonyl group. Z 5 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -O-Z 51 -, -C(=O)-O-Z 51 - or -C(=O)-NH-Z 51 -. Z 51 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond or a hydroxy group. R 21 to R 28 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. R 23 and R 24 , or R 26 and R 27 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. M- is a non-nucleophilic counter ion.

3. The resist material according to claim 1 or 2, wherein the nitroxyl radical is represented by any one of the following formulas (A-1) to (A-3): 【Chemistry 1】 (In the formula, m 1 is 1, 2 or 3. 2 is 1 or 2. n 1 and n 2 is 1≦n 1 ≦5, 0≦n 2 ≦4 and 1≦n 1 +n 2 n is an integer satisfying the condition ≦5. 3 , n 4 and n 5 is 1≦n 3 ≦4, 2≦n 4 ≦4, 0≦n 5 ≦3 and 3≦n 3 +n 4 +n 5 An integer satisfying ≦6. X 1 , X 2A and X 2B are each independently a single bond, an ester bond, an ether bond, or an amide bond. R 1 is a hydroxy group, a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an amino group, -N(R 1A )-C(=O)-R 1B , -N(R 1A )-C(=O)-O-R 1B Or -N(R 1A )-S(=O) 2 -R 1B It is. 1A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 1B represents a saturated hydrocarbyl group having 1 to 6 carbon atoms, an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms, which may be substituted with a halogen atom. R 2 is a hydrocarbyl group having 1 to 20 carbon atoms, which may contain at least one selected from a hydroxy group, a carboxy group, a thioether bond, an ether bond, an ester bond, a nitro group, a cyano group, a sulfonyl group, a halogen atom, and an amino group, provided that it does not contain a phenyl group substituted with an iodine atom. R 3A is m 1 When m is 1, it is a single bond or a hydrocarbylene group having 1 to 10 carbon atoms; 1 When m is 2 or 3, m is a 1 to 10 carbon atom group. 1 +1)valent hydrocarbon group. 3B is a single bond or a hydrocarbylene group having 1 to 10 carbon atoms. 3C is a hydrocarbylene group having 1 to 10 carbon atoms. 1 The monovalent hydrocarbon group may contain at least one selected from a hydroxy group, a carboxy group, a thiol group, an ether bond, an ester bond, a nitro group, a cyano group, a sulfonyl group, a sultone ring, a halogen atom, and an amino group. R 4A and R 4B is a single bond or a hydrocarbylene group having 1 to 10 carbon atoms. 2 and R 4A Or R 4B may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, and in this case, the ring may contain a double bond, an oxygen atom, a sulfur atom or a nitrogen atom. However, the nitroxyl radical represented by formula (A-1) does not include the nitroxyl radical represented by formula (A-3).

4. 2. The resist material according to claim 1, wherein the acid generator generates a sulfonic acid, an imide acid or a methide acid.

5. The resist material according to any one of claims 1 to 4, further comprising an organic solvent.

6. The resist material according to any one of claims 1 to 5, wherein the base polymer contains a repeating unit represented by the following formula (a1) or a repeating unit represented by the following formula (a2): 【Chemistry 2】 (In the formula, R A are each independently a hydrogen atom or a methyl group. Y 1 is a linking group having 1 to 12 carbon atoms containing at least one selected from a single bond, a phenylene group, a naphthylene group, an ester bond, and a lactone ring. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are each independently an acid labile group. R 13 is a fluorine atom, a trifluoromethyl group, a cyano group or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 14 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, some of the carbon atoms of which may be substituted with ether bonds or ester bonds. a is 1 or 2. b is an integer from 0 to 4, provided that 1≦a+b≦5.

7. The resist material of claim 6 which is a chemically amplified positive resist material.

8. 6. The resist material according to claim 1, wherein the base polymer does not contain an acid labile group.

9. The resist material of claim 8 which is a chemically amplified negative resist material.

10. The resist material according to any one of claims 1 to 9, further comprising a surfactant.

11. The resist material according to claim 1, wherein the base polymer further comprises a repeating unit represented by any one of the following formulas (f1) to (f3): 【Chemistry 3】 (In the formula, R A are each independently a hydrogen atom or a methyl group. Z 1 represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or -O-Z 11 -, -C(=O)-O-Z 11 - or -C(=O)-NH-Z 11 - is. 11 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -O-C(=O)-. Z 31 represents a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group obtained by combining these and having 7 to 18 carbon atoms, which may contain a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine atom. Z 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group, or a carbonyl group. Z 5 represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -O-Z 51 -, -C(=O)-O-Z 51 - or -C(=O)-NH-Z 51 - is. 51 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. R 21 ~R 28 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 23 and R 24 and or R 26 and R 27 and may be bonded to each other to form a ring together with the sulfur atom to which they are attached. M - is a non-nucleophilic counterion.)

12. A pattern forming method comprising the steps of: forming a resist film on a substrate using the resist material according to any one of claims 1 to 11; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer.

13. 13. The method for forming a pattern according to claim 12, wherein the high-energy radiation is i-rays having a wavelength of 365 nm, ArF excimer laser light having a wavelength of 193 nm, or KrF excimer laser light having a wavelength of 248 nm.

14. 13. The pattern forming method according to claim 12, wherein the high energy beam is an electron beam or extreme ultraviolet light having a wavelength of 3 to 15 nm.

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