Pattern forming method and resist material

Abstract

To provide a pattern forming method capable of forming a fine pattern with a high aspect ratio without causing pattern collapse.SOLUTION: A pattern forming method comprises preparing a resist material containing a polymer having a silicon-containing acid-labile group, forming a resist film by using the resist material, exposing and baking the resist film, and then developing the resist film by dry etching to form a pattern.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] As LSIs become more highly integrated and faster, pattern rules are becoming increasingly miniaturized. This is due to the increasing popularity of 5G high-speed communications and artificial intelligence (AI), which require high-performance devices to process these technologies. The most advanced miniaturization technology is extreme ultraviolet (EUV) lithography with a wavelength of 13.5 nm, which is currently used to mass-produce 5nm and 3nm node devices. Furthermore, the use of EUV lithography is being considered for next-generation 2nm node devices and the generation after that, the 14Å node, with Belgium's IMEC announcing the development of 2Å devices.

[0003] As miniaturization progresses, image blurring due to acid diffusion has become a problem. To ensure resolution in fine patterns with dimensions of 45 nm and smaller, it has been suggested that controlling acid diffusion is important, in addition to improving dissolution contrast, as has been proposed previously (Non-Patent Document 1). However, because chemically amplified resist materials increase sensitivity and contrast through acid diffusion, attempts to minimize acid diffusion by lowering the post-exposure bake (PEB) temperature or shortening the time result in significant decreases in sensitivity and contrast.

[0004] The triangle trade-off relationship between sensitivity, resolution, and edge roughness (LWR) is shown. To improve resolution, it is necessary to suppress acid diffusion, but as the acid diffusion distance becomes shorter, sensitivity decreases.

[0005] It is effective to suppress acid diffusion by adding an acid generator that generates bulky acid. Therefore, it has been proposed to incorporate repeating units derived from onium salts having polymerizable unsaturated bonds into a polymer. In this case, the polymer also functions as an acid generator (polymer-bound acid generator). Patent Document 1 proposes sulfonium salts and iodonium salts having polymerizable unsaturated bonds that generate specific sulfonic acids. Patent Document 2 proposes sulfonium salts in which sulfonic acids are directly linked to the main chain.

[0006] It has been reported that pattern collapse determines the resolution limit of resists (Non-Patent Document 1). The pattern collapse occurs due to stress applied to the pattern during spin drying after rinsing in alkaline water development. Lowering the surface tension of the rinse solution is effective in reducing stress during spin drying, and rinse solutions containing surfactants have been used for this purpose, but this is insufficient for line patterns with a pattern pitch of 20 nm or less. Rinsing with supercritical carbon dioxide, which reduces surface tension to zero, has been considered, but this requires a special chamber to create a high-pressure supercritical state, making it impractical from the perspective of improving throughput. A method has been proposed in which the gaps between patterns are filled with a water-soluble silicon-containing rinse solution and then dry-etched with oxygen gas, but this method suffers from the problem of image inversion.

[0007] Another proposed pattern formation method is to open up exposed areas by dry etching a resist pattern in which the exposed areas have shrunk due to exposure and PEB deprotection of acid labile groups (Patent Document 3). However, this method also has problems in that if the amount of shrinkage of the exposed areas is large, two-dimensional patterns such as L-shapes may be deformed or the cross-sectional shape of the lines may become triangular. A dry development process has been proposed in which a resist blended with polyphthalaldehyde having trimethylsilyl groups and an acid generator is exposed to PEB, which decomposes and evaporates the polyphthalaldehyde, forming a positive pattern, and then the pattern is transferred to the underlying substrate by oxygen gas etching (Non-Patent Document 2). In this process, the resist film is exposed and then thermally developed while baking to form a pattern. Therefore, to form a good pattern, it is necessary to set PEB conditions that ensure appropriate decomposition of the polyphthalaldehyde. This limits the process conditions, making it difficult to improve sensitivity and resolution.

[0008] Surface imaging, in which the resist surface is made hydrophilic by exposure and deprotection of acid-labile groups by PEB, is treated with a silicon compound gas or solution to silylate the resist surface, and then a pattern is formed by dry etching, has long been studied (Patent Document 4). Surface imaging does not cause pattern collapse, but has the problem of poor line edge roughness (LWR).

[0009] In addition, bilayer resists containing polymers substituted with silicon-containing acid labile groups have been proposed (Non-Patent Document 3, Patent Documents 5 to 7). [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-045311 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-178317 [Patent Document 3] Japanese Patent Application Publication No. 2023-157346 [Patent Document 4] Japanese Patent Application Publication No. 7-22304 [Patent Document 5] Japanese Patent Application Laid-Open No. 2001-278918 [Patent Document 6] Japanese Patent Application Laid-Open No. 2001-158808 [Patent Document 7] Japanese Patent Application Laid-Open No. 2002-105130 [Non-patent literature]

[0011] [Non-Patent Document 1] SPIE Vol. 6153 p61531C-1 (2006) [Non-patent document 2] J. Electrochem. Soc. 136, p245, (1989) [Non-patent document 3] SPIE Vol. 3678 p241 (1999) Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pattern forming method capable of forming a fine pattern with a high aspect ratio without causing pattern collapse. [Means for solving the problem]

[0013] In order to solve the above problems, the present invention provides a pattern formation method comprising: preparing a resist material containing a polymer having a silicon-containing acid labile group; forming a resist film using the resist material; exposing and baking the resist film; and developing the resist film by dry etching to form a pattern.

[0014] The pattern forming method of the present invention makes it possible to form a fine pattern with a high aspect ratio without causing pattern collapse.

[0015] In the present invention, it is preferable to use a polymer having one or more repeating units represented by the following general formulae (a1) to (a3) ​​as the polymer having the silicon-containing acid labile group. [ka] (In the formula, RA are each independently a hydrogen atom or a methyl group. 1 is a linear, branched or cyclic divalent hydrocarbon group having 1 to 12 carbon atoms, which may have a trimethylsilyl group or a trimethylsilyloxy group. 2 R 3 R 4 R is an organic silicon group represented by Si and containing 1 to 4 silicon atoms. 2 , R 3 , R 4 are each independently a linear, branched, or cyclic monovalent aliphatic hydrocarbon group having 1 to 14 carbon atoms, which may have a double bond or a triple bond, and which may have a trimethylsilyl group or a trimethylsilyloxy group, or a trimethylsilyl group or a trimethylsilyloxy group. 5 is a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, which may contain a silicon atom; R 6 is a linear, branched or cyclic hydrocarbon group having 1 to 6 carbon atoms and containing a silicon atom. 1 is a single bond, a phenylene group, a naphthylene group, or -C(=O)-R 7 -R 7 is a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms, which may contain an oxygen atom, a sulfur atom or a nitrogen atom, or a phenylene group or a naphthylene group. 1 is a cyclic organosilicon group having one or more silicon atoms, and the ring Y 2 is a cyclic organic group that does not contain a silicon atom.

[0016] A method using a polymer having a silicon-containing acid labile group with such a repeating unit makes it possible to more suitably form a fine pattern with a high aspect ratio without causing pattern collapse.

[0017] In this case, it is preferable to use a resist material containing a polymer having a repeating unit b having an acid generating moiety in addition to the repeating unit described above.

[0018] By using a polymer incorporating an acid generating moiety (polymer-bound acid generator) in this way, the acid generating function of the resist material can be made suitable.

[0019] Here, it is preferable to use a repeating unit selected from the repeating units represented by the following formulas (b1) to (b5) as the repeating unit b having the acid generating moiety. [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. B are each independently a hydrogen atom or Z 6 may be bonded to form a ring. 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 -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -It is. Z 11 Z 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. 2 is a single bond or an ester bond. 3 is a single bond, -Z 31 -C(=O)-O- or -Z 31 -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, a nitro group, a cyano group, an ester bond, an ether bond, a urethane bond, a fluorine atom, an iodine atom, or a bromine atom. Z 4 is a single bond, a methylene group, or an ethylene group. 5 represents a single bond, a methylene group, an ethylene group, a phenylene group, a methylphenylene group, a dimethylphenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -OZ51 -, -C(=O)-OZ 51 - or -C(=O)-NH-Z 51 -It is. Z 51 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a methylphenylene group, a dimethylphenylene 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, a hydroxy group, or a halogen atom. 6 is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond. 7A represents a single bond or a divalent organic group having 1 to 24 carbon atoms, and may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. 7B is a monovalent organic group having 1 to 10 carbon atoms, which may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. 8 is a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms. 9 is a trivalent organic group having 1 to 12 carbon atoms, and may have at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine with the carbon atom to which they are attached to form a carbonyl group. 21 and R 22 R are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 23 is a saturated hydrocarbyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, an iodine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group, or a nitro group. Ring R is a (d+2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. d is an integer of 0 to 5. X - is a non-nucleophilic counterion. M +is a sulfonium cation or an iodonium cation.

[0020] In the present invention, by using a polymer incorporating a repeating unit b having such an acid generating moiety, it is possible to more preferably form a fine pattern with a high aspect ratio without pattern collapse.

[0021] In this case, the repeating unit b having the acid generating moiety is Z in the above formula. 3 , Z 7A , Z 7B or M + However, repeat units containing one or more iodine atoms can be used.

[0022] By using such a repeating unit containing an iodine atom, more suitable pattern formation becomes possible.

[0023] In the present invention, the exposure can also be carried out using extreme ultraviolet light having a wavelength of 3 to 15 nm or an electron beam having an acceleration voltage of 1 to 150 kV.

[0024] In the present invention, such high-energy rays can be used to more preferably form a fine pattern with a high aspect ratio without causing pattern collapse.

[0025] The present invention also provides a resist material for use in pattern formation by dry etching, which resist material contains a polymer having one or more repeating units represented by the following general formulae (a1) to (a3): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. 1 is a linear, branched or cyclic divalent hydrocarbon group having 1 to 12 carbon atoms, which may have a trimethylsilyl group or a trimethylsilyloxy group. 2 R 3 R 4R is an organic silicon group represented by Si and containing 1 to 4 silicon atoms. 2 , R 3 , R 4 are each independently a linear, branched, or cyclic monovalent aliphatic hydrocarbon group having 1 to 14 carbon atoms, which may have a double bond or a triple bond, and which may have a trimethylsilyl group or a trimethylsilyloxy group, or a trimethylsilyl group or a trimethylsilyloxy group. 5 is a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, which may contain a silicon atom; R 6 is a linear, branched or cyclic hydrocarbon group having 1 to 6 carbon atoms and containing a silicon atom. 1 is a single bond, a phenylene group, a naphthylene group, or -C(=O)-R 7 -R 7 is a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms, which may contain an oxygen atom, a sulfur atom or a nitrogen atom, or a phenylene group or a naphthylene group. 1 is a cyclic organosilicon group having one or more silicon atoms, and the ring Y 2 is a cyclic organic group that does not contain a silicon atom.

[0026] Such a resist material can be suitably used in the pattern forming method of the present invention.

[0027] In the present invention, it is preferable to further contain a repeating unit b having an acid generating moiety containing one or more iodine atoms.

[0028] Such a resist material can more suitably form a fine pattern with a high aspect ratio while suppressing the occurrence of pattern collapse in a pattern formation method using the same.

[0029] In the present invention, it is also preferable that the polymer is a copolymer further having one or more repeating units selected from the repeating units represented by the following formulae (b1) to (b5). [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. B are each independently a hydrogen atom or Z 6 may be bonded to form a ring. 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 -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -It is. Z 11 Z 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. 2 is a single bond or an ester bond. 3 is a single bond, -Z 31 -C(=O)-O- or -Z 31 -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, a nitro group, a cyano group, an ester bond, an ether bond, a urethane bond, a fluorine atom, an iodine atom, or a bromine atom. Z 4 is a single bond, a methylene group, or an ethylene group. 5 represents a single bond, a methylene group, an ethylene group, a phenylene group, a methylphenylene group, a dimethylphenylene 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. Z 51 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a methylphenylene group, a dimethylphenylene 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, a hydroxy group, or a halogen atom. 6is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond. 7A represents a single bond or a divalent organic group having 1 to 24 carbon atoms, and may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. 7B is a monovalent organic group having 1 to 10 carbon atoms, which may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. 8 is a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms. 9 is a trivalent organic group having 1 to 12 carbon atoms, and may have at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine with the carbon atom to which they are attached to form a carbonyl group. 21 and R 22 R are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 23 is a saturated hydrocarbyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, an iodine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group, or a nitro group. Ring R is a (d+2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. d is an integer of 0 to 5. X - is a non-nucleophilic counterion. M + is a sulfonium cation or an iodonium cation.

[0030] Such a resist material can be more suitably used in the pattern forming method of the present invention. [Effects of the Invention]

[0031] In the pattern formation method of the present invention, acid is generated in the resist film upon exposure, which deprotects the silicon-containing acid-labile groups in the polymer, reducing the silicon content, and dry etching opens the exposed areas to form a positive pattern. Etching containing oxygen gas converts the silicon-containing groups to silicon dioxide in the unexposed areas, slowing the etching rate, while the exposed areas, due to their reduced silicon content, have a faster etching rate. A positive pattern is formed by the large difference in etching rate between the exposed and unexposed areas. Development by dry etching prevents pattern collapse due to capillary force, making it possible to form fine patterns with high aspect ratios. DETAILED DESCRIPTION OF THE INVENTION

[0032] As mentioned above, as pattern rules become finer in line with the increasing integration and speed of LSIs, there has been a demand for a pattern formation method that does not cause pattern collapse or deformation.

[0033] As a result of extensive research into achieving the above-mentioned object, the present inventors have found that by using a resist material based on a polymer having repeating units substituted with acid-labile groups having silicon, the unexposed portions have silicon-containing groups, and the exposed portions have a reduced silicon content due to deprotection, and when this is dry-etched, the etching rate of the unexposed portions is slower and the etching rate of the exposed portions is faster, thereby increasing the etching rate selectivity between the exposed and unexposed portions and making it possible to form a fine pattern with a high aspect ratio, thereby completing the present invention.

[0034] That is, the present invention provides a pattern formation method comprising the steps of preparing a resist material containing a polymer (base polymer) having silicon-containing acid labile groups, forming a resist film using the resist material, exposing and baking the resist film, and then developing the resist film by dry etching to form a pattern. Note that hereinafter, the base polymer may also be referred to as a base resin.

[0035] The present invention will be described in detail below, but is not limited thereto. In this specification, the descriptions using the endpoints of a numerical range include all values ​​included in that range. Furthermore, unless otherwise specified, the organic group refers to a hydrocarbon group that may contain a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and may be saturated or unsaturated, linear, branched, or cyclic, and an organic group that further contains a silicon atom is an organosilicon group.

[0036] [Pattern formation method] The pattern forming method of the present invention includes the following steps (i) to (iv): (i) providing a resist material comprising a polymer having repeating units substituted with silicon-containing acid labile groups; (ii) forming a resist film using the resist material and exposing the resist film; (iii) baking the resist film after exposure; and (iv) A step of developing the baked resist film by dry etching to form a pattern. It includes:

[0037] [Step (i)] Step (i) is a step of preparing a resist material containing repeating units substituted with silicon-containing acid labile groups. The resist material will be described in detail below.

[0038] [Step (ii)] In step (ii), a resist film is formed using the resist material, and the resist film is exposed to light. The resist film can be formed, for example, by applying a resist material containing the base resin onto a substrate and then subjecting the substrate to a heat treatment.

[0039] Specifically, for example, the resist material is applied to a substrate for integrated circuit manufacturing or a process layer on the substrate (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective coating, etc.), or to a substrate for mask circuit manufacturing or a process layer on the substrate (Cr, CrO, CrON, MoSi2, SiO2, Ru, Ta, TaB, TaBN, TaBO, etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., to a coating thickness of 0.1 to 2.0 μm. This is then pre-baked on a hot plate at 60 to 150°C for 10 seconds to 30 minutes, preferably 80 to 120°C for 30 seconds to 20 minutes, to form a resist film.

[0040] Next, the resist film is exposed to high-energy rays such as ultraviolet rays, far ultraviolet rays, electron beams (EB) with an acceleration voltage of 1 to 150 kV, extreme ultraviolet rays (EUV) with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer lasers, gamma rays, and synchrotron radiation through a predetermined mask or directly, forming a desired pattern. The exposure dose is 1 to 300 mJ / cm. 2 degree, especially 10-200mJ / cm 2 , or 1 to 500 μC / cm 2 degree, especially 5 to 400 μC / cm 2 is preferred. In the pattern forming method of the present invention, it is particularly preferred that the exposure be carried out using extreme ultraviolet light having a wavelength of 3 to 15 nm or an electron beam having an acceleration voltage of 1 to 150 kV.

[0041] [Step (iii)] Step (iii) is a step of post-exposure baking (PEB) of the resist film at 30 to 170° C. The PEB temperature is preferably 40 to 160° C., more preferably 50 to 150° C., and the treatment time is preferably 10 seconds to 30 minutes, more preferably 10 seconds to 20 minutes.

[0042] In the pattern forming method of the present invention, heating of the PEB after exposure can be carried out not only by a hot plate but also by infrared irradiation, laser irradiation, hot air blowing, or by placing the wafer in an atmosphere at the baking temperature.

[0043] Currently, most wafer heating methods use a hot plate. By placing a silicon wafer on the hot plate, the resist film is heated by heat transfer from the wafer. The temperature of the hot plate is controlled to adjust the temperature to which the resist film is heated.

[0044] [Step (iv)] In step (iv), the resist film is developed by dry etching after baking. The dry etching gas can be a mixed gas of oxygen, hydrogen, ammonia, fluorocarbon, chlorine, or bromine gas diluted with nitrogen, argon, helium, carbon dioxide, carbon monoxide, or sulfur dioxide.

[0045] [Resist materials] As described above, the resist film is a resist material based on a polymer having repeating units substituted with silicon-containing acid labile groups.

[0046] The silicon-containing acid labile group is not particularly limited as long as it protects a polar group such as a carboxyl group in the repeating unit constituting the polymer main chain and can be eliminated by an acid. In particular, the repeating unit substituted with the silicon-containing acid labile group is preferably one represented by any one or more of the following formulae (a1) to (a3) ​​(these repeating units are also collectively referred to as repeating unit a): The repeating unit constituting the main chain of the base polymer has a carboxyl group, and the carboxyl group is protected (substituted) by an acid labile group. This acid labile group is an organic silicon group having a silicon atom. A resist film is formed in a state in which the carboxyl group bonded to the main chain of the base polymer is protected by the acid labile group. Then, by exposing the resist film, the carboxyl group is deprotected by the action of acid. In the following formula, the group that replaces the carboxyl group of the repeating unit, that is, R 1 -SI group, R 5 Ring Y substituted with 1 , R 6 Ring Y substituted with 2 Each is a silicon-containing acid labile group. [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. 1 is a linear, branched or cyclic divalent hydrocarbon group having 1 to 12 carbon atoms, which may have a trimethylsilyl group or a trimethylsilyloxy group. 2 R 3 R 4 R is an organic silicon group represented by Si and containing 1 to 4 silicon atoms. 2 , R 3 , R 4 are each independently a linear, branched, or cyclic monovalent aliphatic hydrocarbon group having 1 to 14 carbon atoms, which may have a double bond or a triple bond, and which may have a trimethylsilyl group or a trimethylsilyloxy group, or a trimethylsilyl group or a trimethylsilyloxy group. 5 is a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, which may contain a silicon atom; R 6 is a linear, branched or cyclic hydrocarbon group having 1 to 6 carbon atoms and containing a silicon atom. 1 is a single bond, a phenylene group, a naphthylene group, or -C(=O)-R 7 -R 7 is a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms, which may contain an oxygen atom, a sulfur atom or a nitrogen atom, or a phenylene group or a naphthylene group. 1 is a cyclic organosilicon group having one or more silicon atoms, and the ring Y 2 is a cyclic organic group that does not contain a silicon atom.

[0047] Examples of monomers that provide the repeating unit represented by formula (a1) (hereinafter also referred to as repeating unit a1) include, but are not limited to, those shown below. A is the same as above. Note that the oxygen atom of the carboxyl group and R 1 may be attached via any of the primary, secondary, or tertiary carbon atoms.

[0048] [ka]

[0049] [ka]

[0050] [ka]

[0051] Examples of monomers that provide repeating units represented by formula (a2) and (a3) ​​(hereinafter also referred to as repeating units a2 and a3, respectively) include, but are not limited to, those shown below. A is the same as above. Note that the oxygen atom of the carboxyl group and the ring Y 1 or ring Y 2 is bonded via a tertiary carbon atom that constitutes the ring.

[0052] [ka]

[0053] [ka]

[0054] In the present invention, the repeating units having silicon-containing acid labile groups represented by the above general formulae (a1) to (a3) ​​can be contained, but repeating units having conventional silicon-free acid labile groups may also be copolymerized.

[0055] Examples of such conventional repeating units ax include those represented by the following formulae (ax1) and (ax2) (also referred to as repeating unit ax1 and repeating unit ax2, respectively; the same applies hereinafter). [ka] In formulas (ax1) and (ax2), R A are each independently a hydrogen atom or a methyl group. 1 is a single bond, a phenylene group, a naphthylene group, or a linking group having 1 to 12 carbon atoms and having an ester bond, an ether bond, or a lactone ring, and may have a halogen atom, a nitro group, a hydroxy group, an alkoxy group, an acyloxy group, or an alkoxycarbonyloxy group. 2 is a single bond, an ester bond or an amide bond. 11 and R 12 is an acid labile group. 13 R is a fluorine atom, a trifluoromethyl group, a cyano group, or an alkyl group having 1 to 6 carbon atoms. 14 is a single bond or a linear or branched 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 of 0 to 4.

[0056] Examples of monomers that provide the repeating unit ax1 include, but are not limited to, those shown below. A and R 11 is the same as above. [ka]

[0057] [ka]

[0058] Examples of monomers that provide the repeating unit ax2 include, but are not limited to, those shown below. A and R 12 is the same as above. [ka]

[0059] R 11 or R 12 The acid labile group represented by the formula (AL-1) may be selected from a variety of groups, and examples thereof include those represented by the following formulae (AL-1) to (AL-3). [ka]

[0060] In formula (AL-1), c is an integer of 0 to 6. L1 is a tertiary hydrocarbyl group having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, a trihydrocarbylsilyl group in which each hydrocarbyl group is a saturated hydrocarbyl group having 1 to 6 carbon atoms, a carbonyl group, or a saturated hydrocarbyl group having 4 to 20 carbon atoms containing an ether bond or an ester bond, or a group represented by formula (AL-3).

[0061] R L1The tertiary hydrocarbyl group represented by the formula (I) may be saturated or unsaturated, and may be branched or cyclic. Specific examples thereof include a tert-butyl group, a tert-pentyl group, a 1,1-diethylpropyl group, a 1-ethylcyclopentyl group, a 1-butylcyclopentyl group, a 1-ethylcyclohexyl group, a 1-butylcyclohexyl group, a 1-ethyl-2-cyclopentenyl group, a 1-ethyl-2-cyclohexenyl group, and a 2-methyl-2-adamantyl group. Examples of the trialkylsilyl group include a trimethylsilyl group, a triethylsilyl group, and a dimethyl-tert-butylsilyl group. The saturated hydrocarbyl group containing a carbonyl group, an ether bond, or an ester bond may be linear, branched, or cyclic, but is preferably cyclic. Specific examples thereof include a 3-oxocyclohexyl group, a 4-methyl-2-oxooxan-4-yl group, a 5-methyl-2-oxoxolan-5-yl group, a 2-tetrahydropyranyl group, and a 2-tetrahydrofuranyl group.

[0062] Examples of the acid labile group represented by formula (AL-1) include a tert-butoxycarbonyl group, a tert-butoxycarbonylmethyl group, a tert-pentyloxycarbonyl group, a tert-pentyloxycarbonylmethyl group, a 1,1-diethylpropyloxycarbonyl group, a 1,1-diethylpropyloxycarbonylmethyl group, a 1-ethylcyclopentyloxycarbonyl group, a 1-ethylcyclopentyloxycarbonylmethyl group, a 1-ethyl-2-cyclopentenyloxycarbonyl group, a 1-ethyl-2-cyclopentenyloxycarbonylmethyl group, a 1-ethoxyethoxycarbonylmethyl group, a 2-tetrahydropyranyloxycarbonylmethyl group, and a 2-tetrahydrofuranyloxycarbonylmethyl group.

[0063] Further, examples of the acid labile group represented by formula (AL-1) include groups represented by the following formulae (AL-1)-1 to (AL-1)-10. [ka] (In the formula, the dashed lines represent bonds.)

[0064] In formulae (AL-1)-1 to (AL-1)-10, c is the same as defined above. L8 are each independently a saturated hydrocarbyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. L9 is a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. L10 is a saturated hydrocarbyl group having 2 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic.

[0065] In formula (AL-2), R L2 and R L3 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10. The saturated hydrocarbyl group may be linear, branched, or cyclic, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, and an n-octyl group.

[0066] In formula (AL-2), R L4 is a hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10, which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Examples of the hydrocarbyl group include saturated hydrocarbyl groups having 1 to 18 carbon atoms, and some of the hydrogen atoms may be substituted with hydroxy groups, alkoxy groups, oxo groups, amino groups, alkylamino groups, etc. Examples of such substituted saturated hydrocarbyl groups include those shown below. [ka] (In the formula, the dashed lines represent bonds.)

[0067] R L2 and R L3 and R L2 and R L4 and, or R L3and R L4 may be bonded to each other to form a ring together with the carbon atom to which they are bonded, or together with the carbon atom and oxygen atom, and in this case, R L2 and R L3 , R L2 and R L4 , or R L3 and R L4 are each independently an alkanediyl group having 1 to 18 carbon atoms, preferably 1 to 10. The ring obtained by combining these groups preferably has 3 to 10 carbon atoms, more preferably 4 to 10 carbon atoms.

[0068] Among the acid labile groups represented by formula (AL-2), linear or branched ones include, but are not limited to, those represented by the following formulae (AL-2)-1 to (AL-2)-69, in which the dashed lines represent bonds. [ka]

[0069] [ka]

[0070] [ka]

[0071] [ka]

[0072] Among the acid labile groups represented by formula (AL-2), examples of cyclic groups include a tetrahydrofuran-2-yl group, a 2-methyltetrahydrofuran-2-yl group, a tetrahydropyran-2-yl group, and a 2-methyltetrahydropyran-2-yl group.

[0073] Further, examples of the acid labile group include groups represented by the following formula (AL-2a) or (AL-2b): The base polymer may be inter- or intramolecularly crosslinked by the acid labile group. [ka] (In the formula, the dashed lines represent bonds.)

[0074] In formula (AL-2a) or (AL-2b), R L11 and R L12 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 8 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. L11 and R L12 may be bonded to each other to form a ring together with the carbon atoms to which they are attached, in which case R L11 and R L12 are each independently an alkanediyl group having 1 to 8 carbon atoms. L13 are each independently a saturated hydrocarbylene group having 1 to 10 carbon atoms. The saturated hydrocarbylene group may be linear, branched, or cyclic. d and e are each independently an integer of 0 to 10, preferably an integer of 0 to 5, and f is an integer of 1 to 7, preferably an integer of 1 to 3.

[0075] In formula (AL-2a) or (AL-2b), L A is an (f+1)-valent aliphatic saturated hydrocarbon group having 1 to 50 carbon atoms, an (f+1)-valent alicyclic saturated hydrocarbon group having 3 to 50 carbon atoms, an (f+1)-valent aromatic hydrocarbon group having 6 to 50 carbon atoms, or an (f+1)-valent heterocyclic group having 3 to 50 carbon atoms. In addition, some of the carbon atoms of these groups may be substituted with heteroatom-containing groups, and some of the hydrogen atoms bonded to carbon atoms of these groups may be substituted with hydroxy groups, carboxy groups, acyl groups, or fluorine atoms. A As L, saturated hydrocarbon groups such as saturated hydrocarbylene groups having 1 to 20 carbon atoms, trivalent saturated hydrocarbon groups, and tetravalent saturated hydrocarbon groups, and arylene groups having 6 to 30 carbon atoms are preferred. The saturated hydrocarbon groups may be linear, branched, or cyclic.B is -C(=O)-O-, -NH-C(=O)-O- or -NH-C(=O)-NH-.

[0076] Examples of the crosslinked acetal group represented by formula (AL-2a) or (AL-2b) include groups represented by the following formulae (AL-2)-70 to (AL-2)-77. [ka] (In the formula, the dashed lines represent bonds.)

[0077] In formula (AL-3), R L5 , R L6 and R L7 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms such as oxygen, sulfur, nitrogen, or fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, alkenyl groups having 2 to 20 carbon atoms, cyclic unsaturated hydrocarbyl groups having 3 to 20 carbon atoms, and aryl groups having 6 to 10 carbon atoms. In addition, R L5 and R L6 and R L5 and R L7 and, or R L6 and R L7 may be bonded to each other to form an alicyclic ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.

[0078] Examples of the group represented by formula (AL-3) include a tert-butyl group, a 1,1-diethylpropyl group, a 1-ethylnorbornyl group, a 1-methylcyclopentyl group, a 1-isopropylcyclopentyl group, a 1-ethylcyclopentyl group, a 1-methylcyclohexyl group, a 2-(2-methyl)adamantyl group, a 2-(2-ethyl)adamantyl group, and a tert-pentyl group.

[0079] Further, examples of the group represented by formula (AL-3) include groups represented by the following formulae (AL-3)-1 to (AL-3)-19. [ka] (In the formula, the dashed lines represent bonds.)

[0080] In formulas (AL-3)-1 to (AL-3)-19, R L14 are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms, or an aryl group having 6 to 20 carbon atoms. L15 and R L17 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 20 carbon atoms. L16 is an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. The aryl group is preferably a phenyl group. R F is a fluorine atom or a trifluoromethyl group, and g is an integer of 1 to 5.

[0081] Further examples of the acid labile group include groups represented by the following formula (AL-3)-20 or (AL-3)-21: The acid labile group may cause intramolecular or intermolecular crosslinking of the polymer. [ka] (In the formula, the dashed lines represent bonds.)

[0082] In formulas (AL-3)-20 and (AL-3)-21, R L14 is the same as above. R L18 is a (h+1)-valent saturated hydrocarbylene group having 1 to 20 carbon atoms or a (h+1)-valent arylene group having 6 to 20 carbon atoms, and may contain a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. The saturated hydrocarbylene group may be linear, branched, or cyclic. h is an integer of 1 to 3.

[0083] Examples of the monomer that provides the repeating unit containing the acid labile group represented by formula (AL-3) include (meth)acrylate esters containing the exo structure represented by formula (AL-3)-22 below. [ka]

[0084] In formula (AL-3)-22, R A is the same as above. R Lc1 R is a saturated hydrocarbyl group having 1 to 8 carbon atoms or an optionally substituted aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. Lc2 ~R Lc11 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 15 carbon atoms which may contain a heteroatom. Examples of the heteroatom include an oxygen atom. Examples of the hydrocarbyl group include an alkyl group having 1 to 15 carbon atoms and an aryl group having 6 to 15 carbon atoms. R Lc2 and R Lc3 and R Lc4 and R Lc6 and R Lc4 and R Lc7 and R Lc5 and R Lc7 and R Lc5 and R Lc11 and R Lc6 and R Lc10 and R Lc8 and R Lc9 and, or R Lc9 and R Lc10 may be bonded to each other to form a ring together with the carbon atom to which they are bonded, and in this case, the group participating in the bond is a hydrocarbylene group having 1 to 15 carbon atoms which may contain a heteroatom. Lc2 and R Lc11 and R Lc8 and R Lc11 and, or R Lc4 and R Lc6 The term "a" means that adjacent carbon atoms may bond to each other without any intervening bond to form a double bond. This formula also represents an enantiomer.

[0085] Here, examples of monomers that provide the repeating unit represented by formula (AL-3)-22 include those described in JP-A-2000-327633. Specific examples include, but are not limited to, those shown below. In the following formula, R A is the same as above. [ka]

[0086] Examples of monomers that provide repeating units containing an acid labile group represented by formula (AL-3) include (meth)acrylic acid esters containing a furandiyl group, a tetrahydrofurandiyl group, or an oxanorbornanediyl group represented by the following formula (AL-3)-23. [ka]

[0087] In formula (AL-3)-23, R A is the same as above. R Lc12 and R Lc13 are each independently a hydrocarbyl group having 1 to 10 carbon atoms. Lc12 and R Lc13 may be bonded to each other to form an alicyclic ring together with the carbon atoms to which they are attached. Lc14 is a furandiyl group, a tetrahydrofurandiyl group, or an oxanorbornanediyl group. Lc15 is a hydrocarbyl group having 1 to 10 carbon atoms which may contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be linear, branched, or cyclic. Specific examples thereof include saturated hydrocarbyl groups having 1 to 10 carbon atoms.

[0088] Examples of monomers that provide the repeating unit represented by formula (AL-3)-23 include, but are not limited to, those shown below. A is the same as above, Ac is an acetyl group, and Me is a methyl group. [ka]

[0089] [ka]

[0090] The base polymer preferably contains a polymer having the repeating unit b having an acid generating moiety in addition to the repeating unit a. By using a polymer incorporating such an acid generating moiety (polymer-bound acid generator), the acid generating function of the resist material can be made favorable.

[0091] The base polymer preferably further contains at least one repeating unit b of an acid generator selected from the repeating units represented by the following formulas (b1) to (b5). [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. B are each independently a hydrogen atom or Z 6 may be bonded to form a ring. 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 -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -It is. Z 11 Z 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. 2 is a single bond or an ester bond. 3 is a single bond, -Z 31 -C(=O)-O- or -Z 31 -O-. Z 31is 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, a nitro group, a cyano group, an ester bond, an ether bond, a urethane bond, a fluorine atom, an iodine atom, or a bromine atom. Z 4 is a single bond, a methylene group, or an ethylene group. 5 represents a single bond, a methylene group, an ethylene group, a phenylene group, a methylphenylene group, a dimethylphenylene 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. Z 51 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a methylphenylene group, a dimethylphenylene 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, a hydroxy group, or a halogen atom. 6 is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond. 7A represents a single bond or a divalent organic group having 1 to 24 carbon atoms, and may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. 7B is a monovalent organic group having 1 to 10 carbon atoms, which may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. 8 is a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms. 9 is a trivalent organic group having 1 to 12 carbon atoms, and may have at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine with the carbon atom to which they are attached to form a carbonyl group. 21and R 22 R are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 23 is a saturated hydrocarbyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, an iodine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group, or a nitro group. Ring R is a (d+2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. d is an integer of 0 to 5. X - is a non-nucleophilic counterion. M + is a sulfonium cation or an iodonium cation.

[0092] Examples of monomers that provide the repeating unit b1 include, but are not limited to, the following: A is the same as above. [ka]

[0093] In formula (b1), X - 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, imidate 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.

[0094] Further examples of the non-nucleophilic counter ion include a sulfonate ion represented by the following formula (b1-1) in which the α-position is substituted with a fluorine atom, and a sulfonate ion represented by the following formula (b1-2) in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group. [ka]

[0095] In formula (b1-1), R 31 is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and may contain an ether bond, an ester bond, a carbonyl group, a lactone ring, or a fluorine atom. The alkyl group and alkenyl group may be linear, branched, or cyclic.

[0096] In formula (b1-2), R 32 is a hydrogen atom, an alkyl group having 1 to 30 carbon atoms, an acyl group having 2 to 30 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aryloxy group having 6 to 20 carbon atoms, and may contain an ether bond, an ester bond, a carbonyl group, or a lactone ring. The alkyl group, acyl group, and alkenyl group may be linear, branched, or cyclic.

[0097] As the non-nucleophilic counter ion, an anion containing bromine or iodine represented by the following formula (b1-3) can also be used.

[0098] [ka]

[0099] In the general formula (b1-3), p is an integer that satisfies 1≦p≦3. q and r are integers that satisfy 1≦q≦5, 0≦r≦3, and 1≦q+r≦5. q is preferably an integer that satisfies 1≦q≦3, more preferably 2 or 3. r is preferably an integer that satisfies 0≦r≦2.

[0100] In the above general formula (b1-3), 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.

[0101] In the above general formula (b1-3), L 11 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.

[0102] In the above general formula (b1-3), L 12 represents 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.

[0103] In the above general formula (b1-3), R 401 is a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom, or an amino group, or a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group, or a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbylcarbonyl group having 2 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, or a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms, which may contain an ether bond, an ester bond, or an amide bond, or —N(R 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D or -N(R 401C )-C(=O)-OR 401D R 401A and R 401B are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 401Cis 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. 401D is 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.

[0104] 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.

[0105] In the above general formula (b1-3), Rf 11 ~Rf 14 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, and at least one of them is a fluorine atom or a trifluoromethyl group. 11 and Rf 12 may combine to form a carbonyl group. 13 and Rf 14 are preferably both fluorine atoms.

[0106] Specific examples of the anion shown in (b1-3) above include the following.

[0107] [ka]

[0108] [ka]

[0109] [ka]

[0110] [ka]

[0111] [ka]

[0112] [ka]

[0113] [ka]

[0114] [ka]

[0115] [ka]

[0116] [ka]

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[0128] [ka]

[0129] [ka] In the above, X BI is a bromine atom or an iodine atom.

[0130] Examples of the anion of the monomer that gives the repeating unit b2 include, but are not limited to, those shown below. A is the same as above. [ka]

[0131] [ka]

[0132] [ka]

[0133] [ka]

[0134] [ka]

[0135] [ka]

[0136] [ka]

[0137] [ka]

[0138] [ka]

[0139] [ka]

[0140] [ka]

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] Examples of the anion of the monomer that gives the repeating unit b3 include, but are not limited to, those shown below. A is the same as above. [ka]

[0145] [ka]

[0146] Specific examples of the anion of the repeating units b4 and b5 include, but are not limited to, the following: BI is an iodine atom or a bromine atom. [ka]

[0147] [ka]

[0148] [ka]

[0149] [ka]

[0150] [ka]

[0151] [ka]

[0152] [ka]

[0153] [ka]

[0154] [ka]

[0155] [ka]

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[0164]

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[0188] [ka]

[0189] [ka]

[0190] [ka]

[0191] [ka]

[0192] [ka]

[0193] [ka]

[0194] [ka]

[0195] The base polymer contains Z in the above formulas (b2) to (b5) as the repeating unit b having an acid generating moiety. 3 , Z 7A , Z 7B or M + However, it is preferred to use a repeating unit containing one or more iodine atoms. M + Specific examples of the sulfonium cation represented by the formula (I) include, but are not limited to, those shown below. [ka]

[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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[0227] M +Specific examples of the iodonium cation represented by the formula (I) include, but are not limited to, those shown below. [ka]

[0228] [ka]

[0229] Iodine atoms have a very high absorption rate for EUV light with a wavelength of 13.5 nm, and it has been confirmed that secondary electrons are generated from iodine during exposure. Therefore, its use in EUV lithography is expected to improve lithography performance. Furthermore, because iodine atoms have a large molecular weight, their presence in an anionic structure reduces acid diffusion. Furthermore, secondary electrons are generated from iodine during EUV exposure, enhancing sensitivity. Therefore, incorporating iodine atoms into the anionic and / or cationic moieties of repeating units containing an acid generating moiety, as needed, can produce resists with high sensitivity, low LWR, and low CDU. Furthermore, because iodine atoms have an electron-withdrawing effect, they are expected to facilitate the elimination (deprotection) of acid-labile groups, facilitating the generation of acidic groups.

[0230] The base polymer may further contain a repeating unit c having an adhesive group selected from a hydroxy group, a carboxy group, a lactone ring, a carbonate group, a thiocarbonate group, a carbonyl group, a cyclic acetal group, an ether bond, an ester bond, a sulfonate ester bond, a cyano group, an amide group, -OC(=O)-S-, and -OC(=O)-NH-.

[0231] Examples of monomers that provide the repeating unit c include, but are not limited to, those shown below. A is the same as above. [ka]

[0232] [ka]

[0233] [ka]

[0234] [ka]

[0235] [ka]

[0236] [ka]

[0237] [ka]

[0238] [ka]

[0239] [ka]

[0240] [ka]

[0241] Furthermore, monomers having adhesive groups described in Japanese Patent Nos. 6020477, 6028744, 6044557, 6044566, and 6052207 can also be copolymerized.

[0242] The base polymer may further contain a repeating unit d that does not contain an amino group but contains an iodine atom. Examples of monomers that provide the repeating unit d include, but are not limited to, the following. In the following formula, R A is the same as above. [ka]

[0243] [ka]

[0244] The base polymer may contain a repeating unit e other than the repeating units described above. Examples of the repeating unit e include those derived from styrene, vinylnaphthalene, indene, acenaphthylene, coumarin, and coumarone.

[0245] In the base polymer, the content ratios (mole fractions) of repeating units a1, a2, a3, b1, b2, b3, b4, b5, c, d, and e with respect to all repeating units are preferably 0≦a1≦1.0, 0≦a2≦1.0, 0≦a3≦1.0, 0<a1+a2+a3≦1.0, 0≦b1≦0.8, 0≦b2≦0.8, 0≦b3≦0.8, 0≦b4≦0.8, 0≦b5≦0.8, 0≦b1+b2+b3+b4+b5≦0.8, 0≦c≦0.5, 0≦d≦0.9, and 0≦e≦0.5; more preferably 0≦a1≦0.9, 0≦a2≦0.9, 0≦a3≦0.9, 0.1≦a1+a2+a3≦0.9, 0≦b1≦0.7, 0≦b2≦0.7, 0≦b3≦0.7, 0≦b4≦0.7, 0≦b5≦0.7, 0≦b1+b2+b3+b4+b5≦0.7, 0≦c≦0.4, 0≦d≦0.8, and 0≦e≦0.4; still more preferably 0≦a1≦0.8, 0≦a2≦0.8, 0≦a3≦0.8, 0.1≦a1+a2+a3≦0.8, 0≦b1≦0.6, 0≦b2≦0.6, 0≦b3≦0.6, 0≦b4≦0.6, 0≦b5≦0.6, 0≦b1+b2+b3+b4+b5≦0.6, 0≦c≦0.35, 0≦d≦0.7, and 0≦e≦0.35. However, a1+a2+a3+b1+b2+b3+b4+b5+c+d+e = 1.0. In this specification, the description based on the endpoints of the numerical range includes all values included in that range.

[0246] To synthesize the base polymer, for example, monomers that provide the above-described repeating units may be heated in an organic solvent with a radical polymerization initiator added thereto to perform polymerization.

[0247] Examples of organic solvents used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, dioxane, propylene glycol monomethyl ether, γ-butyrolactone, and mixed solvents thereof. Examples of polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The polymerization temperature is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

[0248] 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.

[0249] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and after polymerization, the acetoxy group may be deprotected by the alkaline hydrolysis to give hydroxystyrene or hydroxyvinylnaphthalene.

[0250] The base that can be used in alkaline hydrolysis includes aqueous ammonia, triethylamine, etc. The reaction temperature is preferably −20 to 100° C., more preferably 0 to 60° C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0251] The base polymer preferably has a weight-average molecular weight (Mw) of 1,000 to 500,000, more preferably 2,000 to 30,000, as measured by gel permeation chromatography (GPC) using THF as a solvent, relative to polystyrene standards. An Mw of 1,000 or greater provides a resist material with good heat resistance, while an Mw of 500,000 or less reduces the risk of tailing after pattern formation following dry development. The number-average molecular weight (Mn) can also be determined by GPC.

[0252] Furthermore, if the base polymer has a broad molecular weight distribution (Mw / Mn), the presence of low-molecular-weight and high-molecular-weight polymers may result in the appearance of foreign matter on the pattern after exposure, or the pattern shape may be deteriorated. As the pattern rule becomes finer, the effects of Mw and Mw / Mn tend to become greater. Therefore, in order to obtain a resist material that is suitable for use with 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.

[0253] To obtain narrow-dispersity polymers, living radical polymerization can be used in addition to conventional radical polymerization, including nitroxide-mediated radical polymerization (NMP), atom transfer radical polymerization (ATRP), and reversible addition-fragmentation chain transfer (RAFT) polymerization.

[0254] The base polymer may contain two or more polymers with different composition ratios, Mw, or Mw / Mn. Alternatively, a polymer containing the repeating unit a and a polymer not containing the repeating unit a may be blended.

[0255] [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 components described above and the components described below. Specific examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] and

[0145] of JP-A No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, and ethylene glycol monomethyl ether. 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.

[0256] In the resist composition of the present invention, the content of the organic solvent is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass, per 100 parts by mass of the base polymer. The organic solvents may be used singly or in combination of two or more.

[0257] [Quencher] The resist material of the present invention may contain a quencher. The quencher refers to a compound that can trap the acid generated by the acid generator in the resist material, thereby preventing the acid from diffusing into unexposed areas.

[0258] Examples of the quencher include conventional basic compounds. Specific examples of conventional basic compounds include primary, secondary, and 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, and carbamates. Particularly preferred are the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP 2008-111103 A, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate ester bond, and compounds having a carbamate bond described in Japanese Patent No. 3790649 A. Addition of such basic compounds can, for example, further suppress the diffusion rate of acid in the resist film or correct the shape.

[0259] Further, examples of the quencher include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids, carboxylic acids, or fluorinated alkoxides that are not fluorinated at the α-position, as described in JP 2008-158339 A. Sulfonic acids, imide acids, or methide acids that are fluorinated at the α-position are necessary for deprotecting the acid labile group of a carboxylic acid ester, and salt exchange with the onium salt releases sulfonic acids, carboxylic acids, or fluorinated alcohols that are not fluorinated at the α-position. Sulfonic acids, carboxylic acids, and fluorinated alcohols that are not fluorinated at the α-position do not undergo a deprotection reaction, and therefore function as quenchers.

[0260] Specific examples of such quenchers include a compound represented by the following formula (4) (onium salt of sulfonic acid not fluorinated at the α-position), a compound represented by the following formula (5) (onium salt of carboxylic acid), and a compound represented by the following formula (6) (onium salt of alkoxide). [ka]

[0261] In formula (4), R 101 represents a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hydrogen atom or a heteroatom, but excludes those in which the hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group.

[0262] R 101 The hydrocarbyl group having 1 to 40 carbon atoms 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 40 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, a tert-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, and a tricyclo[5.2.1.0] 2,6 ]Cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms such as a decyl group, an adamantyl group, and an adamantylmethyl group; alkenyl groups having 2 to 40 carbon atoms such as a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 40 carbon atoms such as a cyclohexenyl group; phenyl group, naphthyl group, alkylphenyl groups (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, Examples of aryl groups include aryl groups having 6 to 40 carbon atoms such as arylphenyl groups (e.g., 2,4-n-butylphenyl group, 4-n-butylphenyl group), di- or trialkylphenyl groups (e.g., 2,4-dimethylphenyl group, 2,4,6-triisopropylphenyl group), alkylnaphthyl groups (e.g., methylnaphthyl group, ethylnaphthyl group), and dialkylnaphthyl groups (e.g., dimethylnaphthyl group, diethylnaphthyl group); and aralkyl groups having 7 to 40 carbon atoms such as benzyl group, 1-phenylethyl group, and 2-phenylethyl group.

[0263] Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group 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 -CH- groups of the hydrocarbyl group 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, the hydrocarbyl group may contain a hydroxy group, a cyano 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 anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. Specific examples of the hydrocarbyl group containing a heteroatom include heteroaryl groups such as a thienyl group; alkoxyphenyl groups such as a 4-hydroxyphenyl group, a 4-methoxyphenyl group, a 3-methoxyphenyl group, a 2-methoxyphenyl group, a 4-ethoxyphenyl group, a 4-tert-butoxyphenyl group, and a 3-tert-butoxyphenyl group; alkoxynaphthyl groups such as a methoxynaphthyl group, an ethoxynaphthyl group, an n-propoxynaphthyl group, and an n-butoxynaphthyl group; dialkoxynaphthyl groups such as a dimethoxynaphthyl group and a diethoxynaphthyl group; and aryloxoalkyl groups such as a 2-aryl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, and a 2-(2-naphthyl)-2-oxoethyl group.

[0264] In formula (5), R 102 R is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. 102 Specific examples of the hydrocarbyl group represented by R 101 Examples of the hydrocarbyl group include the same groups as those exemplified above. Other specific examples include fluorinated alkyl groups such as a trifluoromethyl group, a trifluoroethyl group, a 2,2,2-trifluoro-1-methyl-1-hydroxyethyl group, and a 2,2,2-trifluoro-1-(trifluoromethyl)-1-hydroxyethyl group; and fluorinated aryl groups such as a pentafluorophenyl group and a 4-trifluoromethylphenyl group.

[0265] In formula (6), R 103is a saturated hydrocarbyl group having 1 to 8 carbon atoms and at least three fluorine atoms, or an aryl group having 6 to 10 carbon atoms and at least three fluorine atoms, which may contain a nitro group.

[0266] In equations (4), (5) and (6), Mq + is an onium cation. The onium cation is preferably a sulfonium cation, an iodonium cation, or an ammonium cation, and more preferably a sulfonium cation. Specific examples of the sulfonium cation include M + Examples of the sulfonium cation represented by the formula: include the same as those exemplified above.

[0267] As the quencher, a sulfonium salt of an iodinated benzene ring-containing carboxylic acid represented by the following formula (7) can also be suitably used. [ka]

[0268] In formula (7), x is an integer of 1 to 5. y is an integer of 0 to 3. z is an integer of 1 to 3.

[0269] In formula (7), R 111 represents a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or 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, or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms, in which some or all of the hydrogen atoms may be substituted with halogen atoms, or -N(R 111A )-C(=O)-R 111B or -N(R 111A )-C(=O)-OR 111B R 111A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 111Bis a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms. When y and / or z is 2 or more, each R 111 may be the same or different from each other.

[0270] In formula (7), L 1 is a single bond or a (z+1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one bond selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxy group, and a carboxy group. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, and saturated hydrocarbylsulfonyloxy group may be linear, branched, or cyclic.

[0271] In formula (7), R 112 , R 113 and R 114 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.

[0272] Specific examples of the compound represented by formula (7) include those described in JP-A-2017-219836 and JP-A-2021-91666.

[0273] Another example of the quencher is the polymer-type quencher described in JP 2008-239918 A. This quencher 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 pattern thinning and rounding of the pattern top when a protective film for immersion lithography is applied.

[0274] Furthermore, betaine-type sulfonium salts described in Japanese Patent No. 6848776 and Japanese Patent Application Laid-Open No. 2020-37544, fluorine-free methide acids described in Japanese Patent Application Laid-Open No. 2020-55797, sulfonium salts of sulfonamides described in Japanese Patent Application Laid-Open No. 5807552, sulfonium salts of sulfonamides containing iodine atoms described in Japanese Patent Application Laid-Open No. 2019-211751, and acid generators that generate phenols, halogens, and carbonic acid can also be used as quenchers.

[0275] When the resist composition of the present invention contains the 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 quencher may be used alone or in combination of two or more types.

[0276] [Other ingredients] In addition to the above-mentioned components, the composition may contain an acid generator (hereinafter also referred to as an externally added acid generator), a surfactant, a water repellency improver, acetylene alcohols, and the like.

[0277] Examples of the acid generator include compounds (photoacid generators) that generate acid in response to actinic rays or radiation. The photoacid generator component may be any compound that generates an acid upon exposure to high-energy rays, but acid generators that generate sulfonic acid, imide acid, or methide acid are preferred. Specific examples of suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate-type acid generators. Specific examples of the acid generator include those described in paragraphs

[0122] to

[0142] of JP 2008-111103 A, JP 2018-5224 A, and JP 2018-25789 A. When the resist material of the present invention contains an externally added acid generator, the content thereof is preferably 0 to 200 parts by weight, and more preferably 0.1 to 100 parts by weight, per 100 parts by weight of the base polymer.

[0278] Specific examples of the surfactant include those described in paragraphs

[0165] and

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

[0279] The water repellency improver improves the water repellency of the resist film surface and can be used in immersion lithography without a top coat. Preferred examples of the water repellency improver include polymers containing fluorinated alkyl groups and polymers containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue with a specific structure, and examples thereof are described in JP-A Nos. 2007-297590 and 2008-111103. The water repellency improver must be soluble 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 PEB and preventing poor opening of the hole pattern after development. When the resist composition of the present invention contains the water repellency improver, the content thereof is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the base polymer. The water repellency improver may be used alone or in combination of two or more.

[0280] Specific 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 the acetylene alcohols, the content thereof is preferably 0 to 5 parts by mass per 100 parts by mass of the base polymer. The acetylene alcohols may be used alone or in combination of two or more.

[0281] [Pattern formation method] When the resist material of the present invention is used in the manufacture of various integrated circuits, known lithography techniques can be applied as necessary. For example, a pattern formation method can include a method comprising the steps of forming a resist film on a substrate using the resist material, exposing the resist film to high-energy rays, and baking the exposed resist film and dry etching it to form a pattern.

[0282] For example, the resist material of the present invention is applied to a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, SiC, TiN, WSi, BPSG, SOG, organic antireflective coating, carbon film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc., to a coating thickness of 0.01 to 2 μm. This is then prebaked 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.

[0283] The substrate may be a multilayer film in which an inorganic film containing Si, Ti, Hf, Sn, W, etc. is laminated under a carbon-based film, or may have a structure in which a carbon-based film is further laminated under an inorganic film.

[0284] Next, the resist film is exposed to high-energy radiation. Specific 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, and synchrotron radiation. When ultraviolet radiation, far ultraviolet radiation, EUV radiation, X-rays, soft X-rays, excimer laser light, gamma rays, and synchrotron radiation are used as the high-energy radiation, the exposure dose is preferably 1 to 200 mJ / cm, either directly or using a mask for forming a desired pattern. 2 approximately, more preferably 10 to 100 mJ / cm 2When EB is used as the high energy beam, the exposure dose is preferably 0.1 to 300 μC / cm 2 approximately, more preferably 0.5 to 200 μC / cm 2 As described above, the resist material of the present invention is particularly suitable for fine patterning using high-energy rays such as 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. Specifically, examples of the pattern forming method include a pattern forming method in which exposure is performed using extreme ultraviolet light with a wavelength of 3 to 15 nm, and a pattern forming method in which exposure is performed using an electron beam with an acceleration voltage of 1 to 150 kV.

[0285] After exposure, PEB can 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. The deprotection reaction during PEB deprotects the silicon-containing acid labile groups, and the silicon-containing deprotecting component evaporates from the film.

[0286] As described above, dry etching is performed after PEB to remove the exposed portions and open the spaces. Dry etching preferably uses a gas containing oxygen, hydrogen, ammonia, or the like, with dilution gases such as nitrogen, helium, argon, carbon dioxide, and carbon monoxide.

[0287] The developed hole or trench pattern can also be shrunk using thermal flow, RELACS, or DSA. A shrink agent is applied to the hole pattern, and the diffusion of an acid catalyst from the resist film during baking causes crosslinking of the shrink agent on the surface of the resist film, resulting in adhesion of the shrink agent 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. Excess shrink agent is removed, and the hole pattern is shrunk.

[0288] As described above, the present invention is characterized by comprising forming a resist film using a resist material containing a base polymer having a silicon-containing acid labile group, exposing and baking the resist film, and then developing the resist film by dry etching to form a pattern. By using a resist material based on a polymer having repeating units substituted with silicon-containing acid labile groups, the unexposed portions have silicon-containing groups, and the exposed portions have reduced silicon content due to deprotection. When this is dry-etched using a gas that selectively reacts with the silicon-containing groups, the etching rate of the unexposed portions slows and the etching rate of the exposed portions increases, thereby increasing the etching rate selectivity between the exposed and unexposed portions. By utilizing the difference in etching rate due to this selective etching, it is possible to form fine patterns with high aspect ratios.

[0289] Thus, in the pattern formation method of the present invention, acid is generated in the resist film upon exposure, deprotecting the silicon-containing acid-labile groups in the polymer and reducing the silicon content, and then dry etching is performed to open the exposed areas to form a pattern. In particular, dry etching using an oxidation reaction gas such as oxygen, for example, etching with an oxygen-containing gas, converts the silicon-containing groups to silicon dioxide in the unexposed areas, slowing the etching rate, while increasing the etching rate in the exposed areas due to the reduced silicon content. This large difference in etching rate between the exposed and unexposed areas results in the formation of a positive-tone pattern. Development by dry etching prevents pattern collapse due to capillary force, making it possible to form fine patterns with high aspect ratios.

[0290] In the case of resist materials containing a large amount of fluorine or iodine, which are highly water-repellent and difficult to dissolve in alkaline developers, residues may be generated after alkaline development. If residues are generated in the spaces around the resist openings, they can cause defects. Residues are particularly likely to be generated in narrow-pitch patterns. The dry development of the present invention can suppress the generation of residues, thereby reducing defects in narrow-pitch patterns.

[0291] The pattern formation method of the present invention is of great technical value in that it can provide a pattern formation method that does not cause pattern collapse or pattern deformation in accordance with the progress of finer pattern rules accompanying the high integration and high speed of LSIs, which has been desired in this technical field. [Example]

[0292] The present invention will be specifically explained below by showing synthesis examples, preparation examples, working examples and comparative examples, but the present invention is not limited to the following examples.

[0293] [Synthesis example] Synthesis of base resin Each monomer was combined and copolymerized in THF, crystallized in methanol, and then repeatedly washed with hexane, isolated, and dried to synthesize the base resins (polymers 1 to 12, comparative polymer 1) with the following compositions. The resulting base resins had the following compositions: 1 Mw and Mw / Mn were confirmed by H-NMR and GPC (solvent: THF, standard: polystyrene).

[0294] [ka]

[0295] [ka]

[0296] [ka]

[0297] [ka]

[0298] [ka]

[0299] [Preparation Examples 1 to 12, Comparative Preparation Example 1] Preparation of resist material A solution of the components shown in Table 1 dissolved in a solvent containing 50 ppm of Omnova surfactant Polyfox 636 was filtered through a 0.2 μm filter to prepare a positive resist material.

[0300] In Table 1, the components are as follows: Acid generator: PAG-1, PAG-2 [ka]

[0301] Quencher: Quencher 1-3 [ka]

[0302] Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (diacetone alcohol)

[0303] [Table 1]

[0304] [Examples 1-1 to 1-12, Comparative Example 1-1] KrF exposure and dry etching evaluation Each resist material (R-1 to R-12, CR-1) was spin-coated onto a Si substrate coated with a 60-nm-thick anti-reflective coating (DUV-42) manufactured by Nissan Chemical Industries, Ltd., and pre-baked at 105°C for 60 seconds using a hot plate to produce a 140-nm-thick resist film. A 90-nm line-and-space pattern was exposed to the resist using an ASML KrF excimer scanner (XT860N, NA 0.8, dipole illumination, 6% halftone phase-shift mask), and PEB was performed on a hot plate at the temperature listed in Table 2 for 60 seconds.

[0305] After the PEB treatment, the wafer was etched using a dry etching apparatus Terius manufactured by Tokyo Electron Limited under the following conditions. Chamber pressure 12.0Pa RF power 600W Bias power 50W Stage temperature: 25℃ O2 gas flow rate 60sccm N2 gas flow rate 200sccm Time 30sec

[0306] The resist film and anti-reflection film in the exposed areas were thinned by dry etching until the Si substrate surface was revealed.

[0307] The exposure dose at which 90 nm lines and spaces were formed at a 1:1 ratio using a Hitachi High-Technologies Corporation CG-6300 measuring SEM was used, and the resist sensitivity was determined. The wafer was then cut, and the cross section of the 90 nm line and space pattern was observed using a Hitachi High-Technologies Corporation S-4100 electron microscope.

[0308] The results are shown in Table 2.

[0309] [Table 2]

[0310] The results shown in Table 2 demonstrate that the use of a resist material based on a polymer copolymerized with a silicon-containing acid labile group makes it possible to form a pattern by dry etching development according to the present invention (Examples 1-1 to 1-12). In the case of the resist material based on a polymer copolymerized with a silicon-free acid labile group in Comparative Example 1-1, the film was lost not only in the exposed areas but also in the unexposed areas.

[0311] The present specification includes the following aspects. [1]: A pattern formation method comprising: preparing a resist material containing a polymer having a silicon-containing acid labile group; forming a resist film using the resist material; exposing and baking the resist film; and developing the resist film by dry etching to form a pattern. [2]: The pattern forming method according to [1], characterized in that the polymer having the silicon-containing acid labile group is a polymer having one or more repeating units represented by the following general formulas (a1) to (a3): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. 1 is a linear, branched or cyclic divalent hydrocarbon group having 1 to 12 carbon atoms, which may have a trimethylsilyl group or a trimethylsilyloxy group. 2 R 3 R 4 R is an organic silicon group represented by Si and containing 1 to 4 silicon atoms. 2 , R 3 , R 4 are each independently a linear, branched, or cyclic monovalent aliphatic hydrocarbon group having 1 to 14 carbon atoms, which may have a double bond or a triple bond, and which may have a trimethylsilyl group or a trimethylsilyloxy group, or a trimethylsilyl group or a trimethylsilyloxy group. 5 is a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, which may contain a silicon atom; R 6 is a linear, branched or cyclic hydrocarbon group having 1 to 6 carbon atoms and containing a silicon atom. 1 is a single bond, a phenylene group, a naphthylene group, or -C(=O)-R 7 -R 7 is a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms, which may contain an oxygen atom, a sulfur atom or a nitrogen atom, or a phenylene group or a naphthylene group. 1 is a cyclic organosilicon group having one or more silicon atoms, and the ring Y 2 is a cyclic organic group that does not contain a silicon atom. [3]: The pattern formation method according to [2], characterized in that a resist material containing a polymer having a repeating unit b having an acid generating moiety in addition to the repeating unit is used. [4]: The pattern forming method according to [3], wherein the repeating unit b having the acid generating moiety is a repeating unit selected from the repeating units represented by the following formulas (b1) to (b5): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. B are each independently a hydrogen atom or Z 6 may be bonded to form a ring. 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 -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -It is. Z 11 Z 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. 2 is a single bond or an ester bond. 3 is a single bond, -Z 31 -C(=O)-O- or -Z 31 -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, a nitro group, a cyano group, an ester bond, an ether bond, a urethane bond, a fluorine atom, an iodine atom, or a bromine atom. Z 4 is a single bond, a methylene group, or an ethylene group. 5 represents a single bond, a methylene group, an ethylene group, a phenylene group, a methylphenylene group, a dimethylphenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -OZ51 -, -C(=O)-OZ 51 - or -C(=O)-NH-Z 51 -It is. Z 51 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a methylphenylene group, a dimethylphenylene 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, a hydroxy group, or a halogen atom. 6 is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond. 7A represents a single bond or a divalent organic group having 1 to 24 carbon atoms, and may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. 7B is a monovalent organic group having 1 to 10 carbon atoms, which may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. 8 is a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms. 9 is a trivalent organic group having 1 to 12 carbon atoms, and may have at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine with the carbon atom to which they are attached to form a carbonyl group. 21 and R 22 R are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 23 is a saturated hydrocarbyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, an iodine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group, or a nitro group. Ring R is a (d+2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. d is an integer of 0 to 5. X - is a non-nucleophilic counterion. M +is a sulfonium cation or an iodonium cation. [5]: As the repeating unit b having the acid generating moiety, Z in the above formula 3 , Z 7A , Z 7B or M + The pattern forming method according to [4], wherein a repeating unit containing one or more iodine atoms is used. [6]: The pattern forming method according to any one of [1] to [5], wherein the exposure is carried out with extreme ultraviolet light having a wavelength of 3 to 15 nm. [7]: The pattern forming method according to any one of [1] to [5], wherein the exposure is carried out with an electron beam having an acceleration voltage of 1 to 150 kV. [8]: A resist material used for pattern formation by dry etching, characterized in that it contains a polymer having one or more repeating units represented by the following general formulas (a1) to (a3): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. 1 is a linear, branched or cyclic divalent hydrocarbon group having 1 to 12 carbon atoms, which may have a trimethylsilyl group or a trimethylsilyloxy group. 2 R 3 R 4 R is an organic silicon group represented by Si and containing 1 to 4 silicon atoms. 2 , R 3 , R 4 are each independently a linear, branched, or cyclic monovalent aliphatic hydrocarbon group having 1 to 14 carbon atoms, which may have a double bond or a triple bond, and which may have a trimethylsilyl group or a trimethylsilyloxy group, or a trimethylsilyl group or a trimethylsilyloxy group. 5 is a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, which may contain a silicon atom; R 6 is a linear, branched or cyclic hydrocarbon group having 1 to 6 carbon atoms and containing a silicon atom. 1is a single bond, a phenylene group, a naphthylene group, or -C(=O)-R 7 -R 7 is a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms, which may contain an oxygen atom, a sulfur atom or a nitrogen atom, or a phenylene group or a naphthylene group. 1 is a cyclic organosilicon group having one or more silicon atoms, and the ring Y 2 is a cyclic organic group that does not contain a silicon atom. [9]: The resist material according to [8], further comprising a repeating unit b having an acid generating moiety containing one or more iodine atoms.

[10] : The resist material according to [8] or [9], wherein the polymer is a copolymer further having one or more repeating units selected from the repeating units represented by the following formulae (b1) to (b5): [ka] (In the formula, R A are each independently a hydrogen atom or a methyl group. B are each independently a hydrogen atom or Z 6 may be bonded to form a ring. 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 -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -It is. Z 11 Z 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. 2 is a single bond or an ester bond. 3 is a single bond, -Z 31 -C(=O)-O- or -Z 31 -O-. Z 31is 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, a nitro group, a cyano group, an ester bond, an ether bond, a urethane bond, a fluorine atom, an iodine atom, or a bromine atom. Z 4 is a single bond, a methylene group, or an ethylene group. 5 represents a single bond, a methylene group, an ethylene group, a phenylene group, a methylphenylene group, a dimethylphenylene 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. Z 51 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a methylphenylene group, a dimethylphenylene 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, a hydroxy group, or a halogen atom. 6 is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond. 7A represents a single bond or a divalent organic group having 1 to 24 carbon atoms, and may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. 7B is a monovalent organic group having 1 to 10 carbon atoms, which may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. 8 is a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms. 9 is a trivalent organic group having 1 to 12 carbon atoms, and may have at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom or a trifluoromethyl group. 1 and Rf 2 may combine with the carbon atom to which they are attached to form a carbonyl group. 21and R 22 R are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 23 is a saturated hydrocarbyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, an iodine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group, or a nitro group. Ring R is a (d+2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. d is an integer of 0 to 5. X - is a non-nucleophilic counterion. M + is a sulfonium cation or an iodonium cation.

[0312] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. A pattern formation method comprising: preparing a resist material containing a polymer having a silicon-containing acid labile group; forming a resist film using the resist material; exposing and baking the resist film; and developing the resist film by dry etching to form a pattern.

2. 2. The pattern formation method according to claim 1, wherein the polymer having a silicon-containing acid labile group is a polymer having at least one repeating unit represented by the following general formulas (a1) to (a3): 【Chemical 1】 (In the formula, R Ａ are each independently a hydrogen atom or a methyl group. １ is a linear, branched or cyclic divalent hydrocarbon group having 1 to 12 carbon atoms, which may have a trimethylsilyl group or a trimethylsilyloxy group. ２ R ３ R ４ R is an organosilicon group represented by Si and containing 1 to 4 silicon atoms. ２ , R ３ , R ４ are each independently a linear, branched or cyclic monovalent aliphatic hydrocarbon group having 1 to 14 carbon atoms, which may have a double bond or a triple bond and which may have a trimethylsilyl group or a trimethylsilyloxy group, or a trimethylsilyl group or a trimethylsilyloxy group. ５ is a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, which may contain a silicon atom; R ６ is a linear, branched or cyclic hydrocarbon group having 1 to 6 carbon atoms and containing a silicon atom. １ represents a single bond, a phenylene group, a naphthylene group, or —C(═O)—R ７ - is. R ７ is a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms, which may contain an oxygen atom, a sulfur atom or a nitrogen atom, or a phenylene group or a naphthylene group. １ is a cyclic organosilicon group having one or more silicon atoms, and the ring Y ２ is a cyclic organic group that does not contain a silicon atom.

3. 3. The pattern formation method according to claim 2, wherein a resist material containing a polymer having a repeating unit b having an acid generating moiety in addition to the repeating unit is used.

4. 4. The pattern formation method according to claim 3, wherein the repeating unit b having the acid generating moiety is a repeating unit selected from the repeating units represented by the following formulas (b1) to (b5): 【Chemistry 2】 (In the formula, R Ａ are each independently a hydrogen atom or a methyl group. Ｂ are each independently a hydrogen atom or Z ６ may be bonded to form a ring. 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. Z 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. ２ is a single bond or an ester bond. ３ is a single bond, -Z ３１ -C(=O)-O- or -Z ３１ -O-. Z ３１ represents 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, a nitro group, a cyano group, an ester bond, an ether bond, a urethane bond, a fluorine atom, an iodine atom, or a bromine atom. ４ is a single bond, a methylene group, or an ethylene group. ５ represents a single bond, a methylene group, an ethylene group, a phenylene group, a methylphenylene group, a dimethylphenylene 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. Z ５１ represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a methylphenylene group, a dimethylphenylene 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, a hydroxy group, or a halogen atom. ６ is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond. ７Ａ represents a single bond or a divalent organic group having 1 to 24 carbon atoms, and may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. ７Ｂ is a monovalent organic group having 1 to 10 carbon atoms, which may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. ８ is a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms. ９ is a trivalent organic group having 1 to 12 carbon atoms, and may have at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. １ ~Rf ４ are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom or a trifluoromethyl group. １ and Rf ２ may combine with the carbon atom to which they are attached to form a carbonyl group. ２１ and R ２２ R are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. ２３ is a saturated hydrocarbyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, an iodine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group, or a nitro group. Ring R is a (d+2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. d is an integer of 0 to 5. X － is a non-nucleophilic counterion. ＋ is a sulfonium cation or an iodonium cation.

5. The repeating unit b having the acid generating moiety is Z in the formula ３ , Z ７Ａ , Z ７Ｂ or M ＋ 5. The pattern formation method according to claim 4, wherein the repeating unit contains one or more iodine atoms.

6. 6. The pattern formation method according to claim 1, wherein the exposure is carried out with extreme ultraviolet light having a wavelength of 3 to 15 nm.

7. 6. The pattern forming method according to claim 1, wherein the exposure is carried out with an electron beam having an acceleration voltage of 1 to 150 kV.

8. A resist material used for pattern formation by dry etching, comprising a polymer having one or more repeating units represented by the following general formulas (a1) to (a3): 【Chemistry 3】 (In the formula, R Ａ are each independently a hydrogen atom or a methyl group. １ is a linear, branched or cyclic divalent hydrocarbon group having 1 to 12 carbon atoms, which may have a trimethylsilyl group or a trimethylsilyloxy group. ２ R ３ R ４ R is an organosilicon group represented by Si and containing 1 to 4 silicon atoms. ２ , R ３ , R ４ are each independently a linear, branched or cyclic monovalent aliphatic hydrocarbon group having 1 to 14 carbon atoms, which may have a double bond or a triple bond and which may have a trimethylsilyl group or a trimethylsilyloxy group, or a trimethylsilyl group or a trimethylsilyloxy group. ５ is a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, which may contain a silicon atom; R ６ is a linear, branched or cyclic hydrocarbon group having 1 to 6 carbon atoms and containing a silicon atom. １ represents a single bond, a phenylene group, a naphthylene group, or —C(═O)—R ７ - is. R ７ is a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms, which may contain an oxygen atom, a sulfur atom or a nitrogen atom, or a phenylene group or a naphthylene group. １ is a cyclic organosilicon group having one or more silicon atoms, and the ring Y ２ is a cyclic organic group that does not contain a silicon atom.

9. 9. The resist material according to claim 8, further comprising a repeating unit b having an acid generating moiety containing one or more iodine atoms.

10. 9. The resist material according to claim 8, wherein the polymer is a copolymer further comprising at least one repeating unit selected from the repeating units represented by the following formulas (b1) to (b5): 【Chemistry 4】 (In the formula, R Ａ are each independently a hydrogen atom or a methyl group. Ｂ are each independently a hydrogen atom or Z ６ may be bonded to form a ring. 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. Z 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. ２ is a single bond or an ester bond. ３ is a single bond, -Z ３１ -C(=O)-O- or -Z ３１ -O-. Z ３１ represents 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, a nitro group, a cyano group, an ester bond, an ether bond, a urethane bond, a fluorine atom, an iodine atom, or a bromine atom. ４ is a single bond, a methylene group, or an ethylene group. ５ represents a single bond, a methylene group, an ethylene group, a phenylene group, a methylphenylene group, a dimethylphenylene 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. Z ５１ represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a methylphenylene group, a dimethylphenylene 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, a hydroxy group, or a halogen atom. ６ is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond. ７Ａ represents a single bond or a divalent organic group having 1 to 24 carbon atoms, and may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. ７Ｂ is a monovalent organic group having 1 to 10 carbon atoms, which may have at least one atom selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom. ８ is a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms. ９ is a trivalent organic group having 1 to 12 carbon atoms, and may have at least one atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom. １ ~Rf ４ are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one is a fluorine atom or a trifluoromethyl group. １ and Rf ２ may combine with the carbon atom to which they are attached to form a carbonyl group. ２１ and R ２２ R are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. ２３ is a saturated hydrocarbyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a fluorine atom, an iodine atom, a trifluoromethoxy group, a difluoromethoxy group, a cyano group, or a nitro group. Ring R is a (d+2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. d is an integer of 0 to 5. X － is a non-nucleophilic counterion. ＋ is a sulfonium cation or an iodonium cation.

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