Positive resist material and pattern forming method

Abstract

To provide a positive resist material which has high sensitivity, high resolution, small LWR, good CDU, and a good pattern shape after exposure, and to provide a pattern forming method.SOLUTION: The positive resist material contains a base polymer containing a repeating unit a represented by the following formula (a).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a positive resist material and a patterning method.

Background Art

[0002] With the increasing integration density and speed of LSIs, the miniaturization of pattern rules has been rapidly progressing. This is because the high-speed communication of 5G and the spread of artificial intelligence (AI) are advancing, and high-performance devices are required to process them. As the most advanced miniaturization technology, mass production of 5nm node and 3nm node devices by extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm is being carried out. Furthermore, studies using EUV lithography are also underway for next-generation 2nm node devices and sub-next-generation 14Å nodes, and IMEC in Belgium has announced the development of 2Å devices.

[0003] As miniaturization progresses, image blur due to acid diffusion has become a problem. In order to ensure the resolution of fine patterns with a processing dimension of 45nm or less, it has been proposed that not only the improvement of the dissolution contrast proposed conventionally but also the control of acid diffusion is important (Non-Patent Document 1). However, since chemically amplified resist materials increase the sensitivity and contrast by acid diffusion, if the post-exposure bake (PEB) temperature is lowered or the time is shortened to suppress acid diffusion to the limit, the sensitivity and contrast will be significantly reduced.

[0004] The triangular trade-off relationship among sensitivity, resolution, and line width roughness (LWR) is shown. In order to improve the resolution, it is necessary to suppress acid diffusion, but when the acid diffusion distance becomes short, the sensitivity decreases.

[0005] It is effective to suppress acid diffusion by adding an acid generator that generates a bulky acid. Therefore, it has been proposed to include a repeating unit derived from an onium salt having a polymerizable unsaturated bond in a polymer. At this time, the polymer also functions as an acid generator (polymer-bound type acid generator). Patent Document 1 proposes a sulfonium salt or iodonium salt having a polymerizable unsaturated bond that generates a specific sulfonic acid. Patent Document 2 proposes a sulfonium salt in which a sulfonic acid is directly bonded to the main chain.

[0006] A resist material added with a polymer-bound type acid generator having an onium salt structure in which an anion having an iodine atom is bonded to the main chain has been proposed (Patent Document 3). By having an iodine atom with a large EUV absorption, the efficiency of the acid generator decomposing during exposure is increased, resulting in increased sensitivity. The amount of photon absorption increases, and the physical contrast can be enhanced.

[0007] A resist material containing a polymer in which the carboxy group of vinyl salicylic acid is substituted with an acid-labile group has been proposed (Patent Document 4). Also, a resist material using a polymer in which both the carboxy group and the phenolic hydroxy group of vinyl salicylic acid are substituted with a cyclic acetal has been proposed (Patent Document 5).

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Non-Patent Documents

[0009] [Non-Patent Document 1] SPIE Vol. 6520 65203L-1 (2007) [Summary of the Invention] [Problems to be Solved by the Invention]

[0010] There is a demand for the development of a positive resist material that is more sensitive than conventional positive resist materials and can improve the line width roughness (LWR) of line patterns and the dimensional uniformity (CDU) of hole patterns.

[0011] The present invention has been made in view of the above circumstances, and provides a positive resist material having high sensitivity, high resolution, small LWR, good CDU, and a good pattern shape after exposure, which exceeds conventional positive resist materials, and a pattern forming method. [Means for Solving the Problems]

[0012] As a result of intensive studies to obtain a positive resist material with high resolution, low LWR, and good CDU, which has been demanded in recent years, it has been necessary to improve the development contrast and suppress swelling in the developer. In the resist material containing a polymer in which only the carboxy group of vinyl salicylic acid described in Patent Document 4 is substituted with an acid-labile group, there is a problem that the dissolution contrast is low because the phenolic hydroxy group is not substituted. The resist material containing a polymer in which both the carboxy group and the phenolic hydroxy group of vinyl salicylic acid described in Patent Document 5 are substituted with an acid-labile group having a cyclic acetal structure, although the dissolution contrast is improved, is insufficient. The inventors have found that a resist material containing a polymer having a structure in which both the carboxy group and the phenolic hydroxy group of an aromatic hydroxy acid such as vinyl salicylic acid are substituted with an acid-labile group having a cyclic acetal structure containing an aromatic group can sufficiently suppress the alkali solubility of the unexposed portion, the exposed portion has an improved dissolution contrast while suppressing swelling, the etching resistance is improved by the introduction of the aromatic group, the LWR and CDU are good, and it is effective as a base polymer of a positive resist material.

[0013] Furthermore, in order to improve the dissolution contrast, by introducing a repeating unit in which the hydrogen atom of the carboxy group or the phenolic hydroxy group is substituted with an acid-labile group, the alkali dissolution rate contrast before and after exposure is significantly high with high sensitivity, the effect of suppressing acid diffusion is high with high sensitivity, it has high resolution, the pattern shape after exposure is good, the LWR is small, and the CDU is good. In particular, it has been found that a positive resist material suitable as a fine pattern forming material for ultra-LSI manufacturing or photomasks can be obtained, and the present invention has been completed.

[0014] That is, the present invention provides the following positive resist material and pattern forming method. 1. A positive resist material containing a base polymer containing a repeating unit a represented by the following formula (a).

Chemical formula

Chemical formula

Advantages of the Invention

[0015] The positive resist material of the present invention is based on a polymer having a structure in which the carboxy group and hydroxy group of an aromatic hydroxy acid such as salicylic acid are substituted with an acid labile group having a cyclic acetal structure containing an aromatic group. The acid labile group is deprotected by the acid generated by exposure, resulting in a polymer having an aromatic hydroxy acid structure such as salicylic acid. This not only has high alkali solubility in the exposed portion but also low swelling, is good, and has a high effect of suppressing acid diffusion. Furthermore, it has high sensitivity, high resolution, a good pattern shape after exposure, a small LWR, excellent CDU, no pull-off or residue in the space portion, and no generation of microbridges connecting between patterns. Aromatic hydroxy acids such as salicylic acid have an effect of reducing the swelling of the carboxy group in an alkali developer because the carboxy group and phenolic hydroxy group form a hydrogen-bonding ring. A polymer having an aromatic hydroxy acid structure such as salicylic acid substituted with an acid labile group has low swelling and an improved alkali dissolution rate, so that the above-described good characteristics can be obtained. Therefore, because of these excellent characteristics, it has extremely high practicality and is very useful as a fine pattern forming material for ultra-LSI manufacturing or photomasks by EB drawing, and a pattern forming material for EB or EUV exposure. The positive resist material of the present invention can be applied to, for example, not only lithography in semiconductor circuit formation but also formation of mask circuit patterns, micromachines, and thin film magnetic head circuit formation.

Embodiments for Carrying Out the Invention

[0016] [Positive resist material] The positive resist material of the present invention contains a base polymer having a structure in which both the carboxy group and the phenolic hydroxy group of an aromatic hydroxy acid are substituted with acid-labile groups having a cyclic acetal structure containing an aromatic group.

[0017] [Base polymer] The base polymer preferably contains a repeating unit a represented by the following formula (a). [Chemical formula]

[0018] In formula (a), m is 0 or 1. n is an integer from 0 to 4.

[0019] In formula (a), R A is a hydrogen atom or a methyl group.

[0020] In formula (a), X 1 is a single bond or an ester bond.

[0021] In formula (a), X 2 is a single bond, a saturated hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group or a naphthylene group. The saturated hydrocarbylene group may be linear, branched or cyclic. Specific examples thereof include alkanediyl groups having 1 to 10 carbon atoms such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group; and cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, adamantanediyl group.

[0022] In formula (a), X 3is a single bond, an ester bond, an ether bond or a carbonyl group.

[0023] In formula (a), R 1 is a hydrocarbyl group having 1 to 8 carbon atoms, a hydroxy group, a hydrocarbyloxy group having 1 to 8 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms, a hydrocarbyloxycarbonyloxy group having 2 to 8 carbon atoms or a halogen atom. The hydrocarbyl group and the hydrocarbyl moieties of the hydrocarbyloxy group, hydrocarbylcarbonyloxy group and hydrocarbyloxycarbonyloxy group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 8 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, sec-pentyl group, 3-pentyl group, tert-pentyl group, neopentyl group, n-hexyl group, n-octyl group; cyclic saturated hydrocarbyl groups having 3 to 8 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group, cyclopropylmethyl group, cyclopropylethyl group, cyclobutylmethyl group, cyclobutylethyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclohexylmethyl group, cyclohexylethyl group, methylcyclopropyl group, methylcyclobutyl group, methylcyclopentyl group, methylcyclohexyl group, ethylcyclopropyl group, ethylcyclobutyl group, ethylcyclopentyl group, ethylcyclohexyl group; alkenyl groups having 2 to 8 carbon atoms such as vinyl group, 1-propenyl group, 2-propenyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group; alkynyl groups having 2 to 8 carbon atoms such as ethynyl group, propynyl group, butynyl group, pentynyl group, hexynyl group, heptynyl group, octynyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 8 carbon atoms such as cyclopentenyl group, cyclohexenyl group, methylcyclopentenyl group, methylcyclohexenyl group, ethylcyclopentenyl group, ethylcyclohexenyl group, norbornenyl group; and groups obtained by combining these.

[0024] In formula (a), R 2 and R 3 are each independently a single bond, a methylene group, an ethylene group, a propylene group or a butylene group, and may be substituted with a halogen atom. However, R 2 and R 3 will not simultaneously be a single bond.

[0025] In formula (a), ring R is a benzene ring or a naphthalene ring, and may be substituted with a hydrocarbyl group having 1 to 8 carbon atoms, a hydroxy group, a hydrocarbyloxy group having 1 to 8 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms, a hydrocarbyloxycarbonyloxy group having 2 to 8 carbon atoms or a halogen atom. The hydrocarbyl moieties of the hydrocarbyl group, hydrocarbyloxy group, hydrocarbylcarbonyloxy group and hydrocarbyloxycarbonyloxy group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include those similar to those exemplified as the hydrocarbyl group represented by R 1 .

[0026] In formula (a), *1 and *2 represent bonds to carbon atoms on the aromatic ring in the formula. The bonding positions of *1 and *2 are not particularly limited, but preferably bond to adjacent carbon atoms on the aromatic ring.

[0027] Specific examples of the monomer that gives repeating unit a include, but are not limited to, those shown below. In the following formulas, R A is the same as described above.

Chemical formula

[0028]

Chemical formula

[0029]

Chemical formula

[0030]

Chem.

[0031]

Chem.

[0032]

Chem.

[0033]

Chem.

[0034]

Chem.

[0035]

Chem.

[0036]

Chem.

[0037]

Chem.

[0038]

Chem.

[0039]

Chem.

[0040]

Chem.

[0041] Examples of the method for synthesizing the monomer include a method of subjecting an aromatic hydroxy acid compound and an indanone compound to a cyclization reaction under an acid catalyst. If the aromatic hydroxy acid compound is substituted with a bromine atom or a hydroxy group, a polymerizable double bond can be introduced by vinylation or methacryloylation after the cyclization reaction.

[0042] The base polymer may further contain a repeating unit b in which a hydrogen atom of a carboxy group or a phenolic hydroxy group is substituted with an acid-labile group. The repeating unit b is further for enhancing the dissolution contrast.

[0043] The repeating unit b preferably contains at least one selected from a repeating unit b1 represented by the following formula (b1) and a repeating unit b2 represented by the following formula (b2).

Chemical formula

[0044] In the formulas (b1) and (b2), R A is independently a hydrogen atom or a methyl group. Y 1 is a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 12 carbon atoms containing at least one selected from an ester bond, an ether bond and a lactone ring, and the phenylene group, naphthylene group and linking group may have at least one selected from a halogen atom, a nitro group, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms and a saturated hydrocarbyloxycarbonyloxy group having 2 to 8 carbon atoms. Y 2 is a single bond, an ester bond or an amide bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are acid-labile groups. R 13is a fluorine atom, a trifluoromethyl group, a cyano group, or an alkyl group having 1 to 6 carbon atoms. R 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and a part of the -CH 2 - of the alkanediyl group may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer from 0 to 4. However, 1 ≦ a + b ≦ 5.

[0045] Examples of the monomer that gives the repeating unit b1 include, but are not limited to, those shown below. In the following formulas, R A and R 11 are the same as described above.

Chemical formula

[0046]

Chemical formula

[0047]

Chemical formula

[0048] Examples of the monomer that gives the repeating unit b2 include, but are not limited to, those shown below. In the following formulas, R A and R 12 are the same as described above.

Chemical formula

[0049] R 11 or R 12 As the acid-labile group represented by, various ones are selected. For example, those represented by the following formulas (AL-1) to (AL-3) are included.

Chemical formula

[0050] In formula (AL-1), c is an integer from 0 to 6. R 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 saturated hydrocarbyl group having 4 to 20 carbon atoms containing a carbonyl group, an ether bond or an ester bond, or a group represented by formula (AL-3). The tertiary hydrocarbyl group means a group obtained by detaching a hydrogen atom from a tertiary carbon atom of a hydrocarbon.

[0051] R L1 The tertiary hydrocarbyl group represented by 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, a 2-methyl-2-adamantyl group and the like. Examples of the trihydrocarbylsilyl group include a trimethylsilyl group, a triethylsilyl group, a dimethyl-tert-butylsilyl group and the like. The saturated hydrocarbyl group containing a carbonyl group, an ether bond or an ester bond may be linear, branched or cyclic, but cyclic ones are preferred, and specific examples thereof include a 3-oxocyclohexyl group, a 4-methyl-2-oxooxan-4-yl group, a 5-methyl-2-oxooxolan-5-yl group, a 2-tetrahydropyranyl group, a 2-tetrahydrofuranyl group and the like.

[0052] 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-cyclopentenyl-oxycarbonyl group, a 1-ethyl-2-cyclopentenyl-oxycarbonylmethyl group, a 1-ethoxyethoxycarbonylmethyl group, a 2-tetrahydropyranyloxycarbonylmethyl group, a 2-tetrahydrofuranyloxycarbonylmethyl group, and the like.

[0053] Furthermore, examples of the acid-labile group represented by formula (AL-1) also include groups represented by the following formulas (AL-1)-1 to (AL-1)-10.

Chemical formula

[0054] In formulas (AL-1)-1 to (AL-1)-10, c is the same as described above. R L8 is each independently a saturated hydrocarbyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms. R L9 is a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. R 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.

[0055] In formula (AL-2), R L2 and R L3Each is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms. The saturated hydrocarbyl group may be linear, branched or cyclic, and specific examples thereof include 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, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, an n-octyl group and the like.

[0056] In formula (AL-2), R L4 is a hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, 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 thereof may be substituted with a hydroxy group, an alkoxy group, an oxo group, an amino group, an alkylamino group or the like. Examples of such a substituted saturated hydrocarbyl group include those shown below.

Chemical formula

[0057] R L2 and R L3 and, R L2 and R L4 and, or R L3 and R L4 and may combine with each other to form a ring together with the carbon atom to which they are attached, or together with a carbon atom and an oxygen atom. 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 carbon atoms. The number of carbon atoms in the ring formed by their combination is preferably 3 to 10, more preferably 4 to 10.

[0058] 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 formulas (AL-2)-1 to (AL-2)-69. In the following formulas, the dashed line represents a bond.

Chem.

[0059]

Chem.

[0060]

Chem.

[0061]

Chem.

[0062] Among the acid-labile groups represented by formula (AL-2), cyclic ones include tetrahydrofuran-2-yl group, 2-methyltetrahydrofuran-2-yl group, tetrahydropyran-2-yl group, 2-methyltetrahydropyran-2-yl group, and the like.

[0063] In addition, examples of the acid-labile group include a group represented by the following formula (AL-2a) or (AL-2b). The base polymer may be crosslinked intermolecularly or intramolecularly by the acid-labile group.

Chem.

[0064] 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. Also, R L11 and R L12which may combine with 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. R 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.

[0065] In formula (AL-2a) or (AL-2b), L A is a (f + 1)-valent aliphatic saturated hydrocarbon group having 1 to 50 carbon atoms, a (f + 1)-valent alicyclic saturated hydrocarbon group having 3 to 50 carbon atoms, a (f + 1)-valent aromatic hydrocarbon group having 6 to 50 carbon atoms or a (f + 1)-valent heterocyclic group having 3 to 50 carbon atoms. Further, a part of -CH 2 - of these groups may be substituted with a heteroatom-containing group, and a part of the hydrogen atoms of these groups may be substituted with a hydroxy group, a carboxy group, an acyl group or a fluorine atom. As L A , a saturated hydrocarbon group such as a saturated hydrocarbylene group having 1 to 20 carbon atoms, a trivalent saturated hydrocarbon group, a tetravalent saturated hydrocarbon group, and an arylene group having 6 to 30 carbon atoms are preferable. The saturated hydrocarbon group may be linear, branched or cyclic. L B is -C(=O)-O-, -NH-C(=O)-O- or -NH-C(=O)-NH-.

[0066] Examples of the crosslinked acetal group represented by formula (AL-2a) or (AL-2b) include groups represented by the following formulas (AL-2)-70 to (AL-2)-77.

Chemical formula

[0067] In formula (AL-3), R L5 , R L6 and R L7is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include an alkyl group having 1 to 20 carbon atoms, a cyclic saturated hydrocarbyl group having 3 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a cyclic unsaturated hydrocarbyl group having 3 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, and the like. Also, R L5 and R L6 and, R L5 and R L7 and, or R L6 and R L7 and may combine with each other to form an alicyclic ring having 3 to 20 carbon atoms together with the carbon atoms to which they are attached.

[0068] 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-ethylcyclopentyl group, a 1-isopropylcyclopentyl group, a 1-methylcyclohexyl group, a 2-(2-methyl)adamantyl group, a 2-(2-ethyl)adamantyl group, a tert-pentyl group, and the like.

[0069] Also, examples of the group represented by formula (AL-3) include groups represented by the following formulas (AL-3)-1 to (AL-3)-19.

Chemical formula

[0070] In formulas (AL-3)-1 to (AL-3)-19, R L14 is independently a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 8 carbon atoms, or an aryl group having 6 to 20 carbon atoms. R L15 and R L17 are independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 20 carbon atoms. R L16is an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. Further, as the aryl group, a phenyl group or the like is preferable. R F is a fluorine atom or a trifluoromethyl group. g is an integer of 1 to 5.

[0071] Furthermore, examples of the acid-labile group include a group represented by the following formula (AL-3)-20 or (AL-3)-21. The polymer may be crosslinked intramolecularly or intermolecularly by the acid-labile group.

Chemical formula

[0072] In formula (AL-3)-20 and (AL-3)-21, R L14 is the same as described 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 hetero atom 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.

[0073] The base polymer may further contain a repeating unit c having an adhesion 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 sulfonic acid ester bond, a cyano group, an amide group, -O-C(=O)-S-, and -O-C(=O)-NH-.

[0074] Examples of the monomer that provides the repeating unit c include, but are not limited to, the following. In the following formula, R A is the same as described above.

Chemical formula

[0075] [Chemistry]

[0076] [Chemistry]

[0077] [Chemistry]

[0078] [Chemistry]

[0079] [Chemistry]

[0080] [Chemistry]

[0081] [Chemistry]

[0082] [Chemistry]

[0083] [Chemistry]

[0084] [Chemistry]

[0085] [Chemistry]

[0086] [Chemical formula]

[0087] The base polymer may contain a repeating unit d that functions as an acid generator. The repeating unit d is preferably at least one selected from the repeating unit represented by the following formula (d1) (hereinafter also referred to as repeating unit d1), the repeating unit represented by the following formula (d2) (hereinafter also referred to as repeating unit d2), the repeating unit represented by the following formula (d3) (hereinafter also referred to as repeating unit d3), the repeating unit represented by the following formula (d4) (hereinafter also referred to as repeating unit d4), and the repeating unit represented by the following formula (d5) (hereinafter also referred to as repeating unit d5). [Chemical formula]

[0088] In formulas (d1) to (d3), R A is independently a hydrogen atom or a methyl group.

[0089] In formula (d1), Z 1 is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or -O-Z 11 -, -C(=O)-O-Z 11 - or -C(=O)-NH-Z 11 -. Z 11 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group.

[0090] In formula (d1), R 21 and R 22is independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include those similar to the ones exemplified as the hydrocarbyl groups having 1 to 20 carbon atoms represented by R 41 ~R 45 in the description of formulas (M1) and (M2) described later.

[0091] Examples of the cation of the monomer that gives the repeating unit d1 include, but are not limited to, those shown below. In the following formulas, R A is the same as described above. [Chemical formula]

[0092] In formula (d1), 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, imide ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion and bis(perfluorobutylsulfonyl)imide ion, and methide ions such as tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0093] As the non-nucleophilic counter ion, further examples include sulfonate ions in which the α-position is substituted with a fluorine atom and represented by the following formula (d1-1), sulfonate ions in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group and represented by the following formula (d1-2), and the like.

Chemical formula

[0094] In formula (d1-1), R 31 is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain an ether bond, an ester bond, a carbonyl group, a lactone ring, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic.

[0095] In formula (d1-2), R 32 is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbylcarbonyl group having 2 to 30 carbon atoms, and the hydrocarbyl group and the hydrocarbylcarbonyl group may contain an ether bond, an ester bond, a carbonyl group, or a lactone ring. The hydrocarbyl group and the hydrocarbylcarbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic.

[0096] As the non-nucleophilic counter ion, an anion containing an aromatic ring substituted with a bromine atom or an iodine atom and represented by the following formula (d1-3) can also be used.

Chemical formula

[0097] In formula (d1-3), p is an integer satisfying 1 ≤ p ≤ 3. q and r are integers satisfying 1 ≤ q ≤ 5, 0 ≤ r ≤ 3, and 1 ≤ q + r ≤ 5. It is preferable that q is an integer satisfying 1 ≤ q ≤ 3, and more preferably 2 or 3. It is preferable that r is an integer satisfying 0 ≤ r ≤ 2.

[0098] In formula (d1-3), X BIis an iodine atom or a bromine atom, and when p and / or q are 2 or more, they may be the same as or different from each other.

[0099] In formula (d1-3), L 1 is a single bond, an ether bond or an ester bond, or a saturated hydrocarbylene group having 1 to 6 carbon atoms which may contain an ether bond or an ester bond. The saturated hydrocarbylene group may be linear, branched or cyclic.

[0100] In formula (d1-3), L 2 is a single bond or a divalent linking group having 1 to 20 carbon atoms when p is 1, and 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.

[0101] In formula (d1-3), R 33 is a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom or 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 a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group or an ether bond, or -N(R 33A )(R 33B ), -N(R 33C )-C(=O)-R 33D or -N(R 33C )-C(=O)-O-R 33D . R 33A and R 33B are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 33C is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. R33D 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 hydrocarbyl group, hydrocarbyloxy group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When p and / or r is 2 or more, each R 33 may be the same as or different from each other.

[0102] Among these, R 33 is preferably a hydroxy group, -N(R 33C )-C(=O)-R 33D , -N(R 33C )-C(=O)-O-R 33D , a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group, etc.

[0103] In formula (d1-3), Rf 1 to Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, and at least one of these is a fluorine atom or a trifluoromethyl group. Further, Rf 1 and Rf 2 may combine to form a carbonyl group. In particular, it is preferable that both Rf 3 and Rf 4 are fluorine atoms.

[0104] Examples of the anion represented by formula (d1-3) include, but are not limited to, those shown below. In the following formulas, X BI is the same as described above.

Chemical formula

[0105]

Chem.

[0106]

Chem.

[0107]

Chem.

[0108]

Chem.

[0109]

Chem.

[0110]

Chem.

[0111]

Chem.

[0112]

Chem.

[0113]

Chem.

[0114]

Chem.

[0115]

Chem.

[0116]

Chem.

[0117]

Chem.

[0118]

Chem.

[0119]

Chem.

[0120]

Chem.

[0121]

Chem.

[0122]

Chem.

[0123]

Chem.

[0124]

Chem.

[0125]

Chem.

[0126] [Chemical formula]

[0127] In formula (d2), Z 2 is a single bond or an ester bond. Z 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.

[0128] In formula (d2), Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that at least one of them is a fluorine atom or a trifluoromethyl group. Also, Rf 1 and Rf 2 may combine to form a carbonyl group.

[0129] Examples of the anion of the monomer that gives the repeating unit d2 include, but are not limited to, those shown below. In the following formulas, R A is the same as described above. [Chemical formula]

[0130] [Chemical formula]

[0131] [Chemical formula]

[0132] [Chemistry]

[0133] [Chemistry]

[0134] [Chemistry]

[0135] [Chemistry]

[0136] [Chemistry]

[0137] [Chemistry]

[0138] [Chemistry]

[0139] [Chemistry]

[0140] [Chemistry]

[0141] [Chemistry]

[0142] [Chemistry]

[0143]

Chem.

[0144]

Chem.

[0145] In formula (d3), Z 5 is 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 -. 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.

[0146] Examples of the anion of the monomer that gives the repeating unit d3 include, but are not limited to, those shown below. In the following formulas, R A is the same as described above.

Chem.

[0147]

Chem.

[0148] In formulas (d4) and (d5), R A is each independently a hydrogen atom or a methyl group. R B is each independently a hydrogen atom or may combine with Z 6 to form a ring.

[0149] In formulas (d4) and (d5), Z 6 is a single bond, a phenylene group, a naphthylene ring, an ester bond or an amide bond.

[0150] In formula (d4), Z 7A is a single bond or a divalent organic group having 1 to 24 carbon atoms, and may have at least one selected from a halogen atom, an oxygen atom, a nitrogen atom and a sulfur atom.

[0151] Z 7AThe divalent organic group represented by [[]] is optionally saturated or unsaturated and may be linear, branched or cyclic. Specific examples thereof include C1-C24 hydrocarbylene groups in which some or all of the hydrogen atoms are substituted with iodine atoms or bromine atoms. Examples of the C1-C24 hydrocarbylene group include alkanediyl groups such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, octadecane-1,18-diyl group, nonadecane-1,19-diyl group, eicosane-1,20-diyl group; cyclic saturated hydrocarbylene groups such as cyclopentanediyl group, methylcyclopentanediyl group, dimethylcyclopentanediyl group, trimethylcyclopentanediyl group, tetramethylcyclopentanediyl group, cyclohexanediyl group, methylcyclohexanediyl group, dimethylcyclohexanediyl group, trimethylcyclohexanediyl group, tetramethylcyclohexanediyl group, norbornanediyl group, adamantanediyl group; arylene groups such as phenylene group, methylphenylene group, ethylphenylene group, n-propylphenylene group, isopropylphenylene group, n-butylphenylene group, isobutylphenylene group, sec-butylphenylene group, tert-butylphenylene group, naphthylene group, methylnaphthylene group, ethylnaphthylene group, n-propylnaphthylene group, isopropylnaphthylene group, n-butylnaphthylene group, isobutylnaphthylene group, sec-butylnaphthylene group, tert-butylnaphthylene group, biphenyldiyl group, methylbiphenyldiyl group, dimethylbiphenyldiyl group; and groups obtained by combining these. Further, Z 7A Some or all of the hydrogen atoms of [[]] may be substituted with a group containing at least one selected from oxygen atoms, nitrogen atoms and sulfur atoms, and Z7A -CH 2 - part of which may be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, may contain a hydroxy group, an ester bond, an ether bond, an amide bond, a carbamate bond, a urea bond, etc.

[0152] In formula (d5), Z 7B is a monovalent organic group having 1 to 10 carbon atoms and may have at least one selected from a halogen atom, an oxygen atom, a nitrogen atom, and a sulfur atom.

[0153] Z 7BThe monovalent organic group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include hydrocarbyl groups having 1 to 10 carbon atoms in which part or all of the hydrogen atoms are substituted with iodine atoms or bromine atoms. Examples of the hydrocarbyl group having 1 to 10 carbon atoms include alkyl groups having 1 to 10 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, sec-pentyl group, 3-pentyl group, tert-pentyl group, neopentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group; cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, adamantyl group, norbornyl group, cyclopropylmethyl group, cyclopropylethyl group, cyclobutylmethyl group, cyclobutylethyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclohexylmethyl group, cyclohexylethyl group, methylcyclopropyl group, methylcyclobutyl group, methylcyclopentyl group, methylcyclohexyl group, ethylcyclopropyl group, ethylcyclobutyl group, ethylcyclopentyl group, ethylcyclohexyl group; alkenyl groups having 2 to 10 carbon atoms such as vinyl group, 1-propenyl group, 2-propenyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, nonenyl group, decenyl group; alkynyl groups having 2 to 10 carbon atoms such as ethynyl group, propynyl group, butynyl group, pentynyl group, hexynyl group, heptynyl group, octynyl group, nonynyl group, decynyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 10 carbon atoms such as cyclopentenyl group, cyclohexenyl group, methylcyclopentenyl group, methylcyclohexenyl group, ethylcyclopentenyl group, ethylcyclohexenyl group, norbornenyl group; aryl groups having 6 to 10 carbon atoms such as phenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, isopropylphenyl group, n-butylphenyl group, isobutylphenyl group, sec-butylphenyl group, tert-butylphenyl group, naphthyl group; aralkyl groups having 7 to 10 carbon atoms such as benzyl group, phenethyl group, phenylpropyl group, phenylbutyl group; groups obtained by combining these, etc. Further, Z7B Some or all of the hydrogen atoms of may be substituted with at least one group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and Z 7B -CH 2 - part of may be substituted with at least one group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, it may contain a hydroxy group, an ester bond, an ether bond, an amide bond, a carbamate bond, a urea bond, etc.

[0154] In formulas (d4) and (d5), Z 8 is a single bond, an ether bond, an ester bond, a thioether bond, or an alkanediyl group having 1 to 6 carbon atoms.

[0155] In formula (d5), Z 9 is a trivalent organic group having 1 to 12 carbon atoms, and may have at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom. Z 9 The trivalent organic group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include a group obtained by further eliminating one hydrogen atom from a hydrocarbylene group having 1 to 12 carbon atoms. Examples of the hydrocarbylene group having 1 to 12 carbon atoms include those having 1 to 12 carbon atoms among the above-described hydrocarbylene groups having 1 to 24 carbon atoms. Further, some or all of the hydrogen atoms of Z 9 may be substituted with at least one group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and Z 9 -CH 2 - part of may be substituted with at least one group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, it may contain a hydroxy group, an ester bond, an ether bond, an amide bond, a carbamate bond, a urea bond, etc.

[0156] In formulas (d4) and (d5), R 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.

[0157] In formulas (d4) and (d5), the circle R is a (j + 2)-valent aromatic hydrocarbon group having 6 to 10 carbon atoms. Specific examples of the (j + 2)-valent aromatic hydrocarbon group include groups obtained by eliminating (j + 2) hydrogen atoms from aromatic hydrocarbons such as benzene and naphthalene.

[0158] In formulas (d4) and (d5), j is an integer from 0 to 5.

[0159] Specific examples of the anions of the repeating units d4 and d5 include, but are not limited to, those shown below. In the following formulas, R A is the same as described above, and X BI is an iodine atom or a bromine atom.

Chemical formula

[0160]

Chemical formula

[0161]

Chemical formula

[0162]

Chemical formula

[0163]

Chemical formula

[0164]

Chemical formula

[0165]

Chemical formula

[0166]

Chem.

[0167]

Chem.

[0168]

Chem.

[0169]

Chem.

[0170]

Chem.

[0171]

Chem.

[0172]

Chem.

[0173]

Chem.

[0174]

Chem.

[0175]

Chem.

[0176]

Chem.

[0177]

Chem.

[0178]

Chem.

[0179]

Chem.

[0180]

Chem.

[0181]

Chem.

[0182]

Chem.

[0183]

Chem.

[0184]

Chem.

[0185]

Chem.

[0186]

Chem.

[0187] [Chemistry]

[0188] [Chemistry]

[0189] [Chemistry]

[0190] [Chemistry]

[0191] [Chemistry]

[0192] [Chemistry]

[0193] [Chemistry]

[0194] [Chemistry]

[0195] [Chemistry]

[0196] [Chemistry]

[0197] [Chemistry]

[0198]

Chem.

[0199]

Chem.

[0200]

Chem.

[0201]

Chem.

[0202]

Chem.

[0203]

Chem.

[0204]

Chem.

[0205]

Chem.

[0206]

Chem.

[0207]

Chem.

[0208]

Chem.

[0209]

Chem.

[0210]

Chem.

[0211] In formulas (d2) to (d5), M + is a sulfonium cation or an iodonium cation. As the sulfonium cation, those represented by the following formula (M1) are preferable, and as the iodonium cation, those represented by the following formula (M2) are preferable.

Chem.

[0212] In formulas (M1) and (M2), R 41 ~R 45 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom.

[0213] R 41 ~R 45 Specific examples of the halogen atom represented by R

[0214] R 41 ~R 45The hydrocarbyl group represented by has 1 to 20 carbon atoms and may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group; C3-C20 cyclic saturated hydrocarbyl groups such as cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, adamantyl group; C2-C20 alkenyl groups such as vinyl group, propenyl group, butenyl group, hexenyl group; C2-C20 alkynyl groups such as ethynyl group, propynyl group, butynyl group; C3-C20 cyclic unsaturated aliphatic hydrocarbyl groups such as cyclohexenyl group, norbornenyl group; C6-C20 aryl groups such as phenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, isopropylphenyl group, n-butylphenyl group, isobutylphenyl group, sec-butylphenyl group, tert-butylphenyl group, naphthyl group, methylnaphthyl group, ethylnaphthyl group, n-propylnaphthyl group, isopropylnaphthyl group, n-butylnaphthyl group, isobutylnaphthyl group, sec-butylnaphthyl group, tert-butylnaphthyl group; C7-C20 aralkyl groups such as benzyl group, phenethyl group; groups obtained by combining these, and the like.

[0215] Further, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc. The -CH of the hydrocarbyl group 2- may be partially substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a mercapto group, a pentafluorosulfanyl group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0216] Also, R 41 and R 42 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. At this time, the ring is preferably one having the following structure.

Chemical formula

[0217] M + Specific examples of the sulfonium cation represented by include, but are not limited to, those shown below.

Chemical formula

[0218]

Chemical formula

[0219]

Chemical formula

[0220]

Chemical formula

[0221]

Chemical formula

[0222] [Chemistry]

[0223] [Chemistry]

[0224] [Chemistry]

[0225] [Chemistry]

[0226] [Chemistry]

[0227] [Chemistry]

[0228] [Chemistry]

[0229] [Chemistry]

[0230] [Chemistry]

[0231] [Chemistry]

[0232] [Chemistry]

[0233]

Chem.

[0234]

Chem.

[0235]

Chem.

[0236]

Chem.

[0237]

Chem.

[0238]

Chem.

[0239]

Chem.

[0240]

Chem.

[0241]

Chem.

[0242]

Chem.

[0243] [Chemical]

[0244] [Chemical]

[0245] [Chemical]

[0246] [Chemical]

[0247] [Chemical]

[0248] [Chemical]

[0249] [Chemical]

[0250] [Chemical]

[0251] [Chemical]

[0252] M + Specific examples of the iodonium cation represented by M include, but are not limited to, those shown below. [Chemical]

[0253] [Chemical formula]

[0254] The repeating unit d is the repeating unit d2, d4 or d5, and Z 3 , Z 7A , Z 7B or M + preferably contains at least one iodine atom.

[0255] The repeating units d1 to d5 function as an acid generator. By bonding the acid generator to the polymer main chain, acid diffusion can be reduced, and a decrease in resolution due to blurring of acid diffusion can be prevented. In addition, the LWR and CDU are improved by the uniform dispersion of the acid generator. When using a base polymer containing the repeating units d1 to d5 (that is, a polymer-bound acid generator), the blending of the additive acid generator described later can be omitted.

[0256] The base polymer may further contain a repeating unit e containing an iodine atom and not containing an amino group. Examples of the monomer that provides the repeating unit e include, but are not limited to, the following. In the following formula, R A is the same as described above. [Chemical formula]

[0257] [Chemical formula]

[0258] The base polymer may contain a repeating unit f other than the repeating units described above. Examples of the repeating unit f include those derived from styrene, vinylnaphthalene, indene, acenaphthylene, coumarin, coumarone, etc.

[0259] In the base polymer, the content ratios of repeating units a, b1, b2, c, d1, d2, d3, d4, d5, e, and f are preferably 0 < a ≤ 0.8, 0 ≤ b1 ≤ 0.8, 0 ≤ b2 ≤ 0.8, 0 ≤ b1 + b2 ≤ 0.8, 0 ≤ c ≤ 0.9, 0 ≤ d1 ≤ 0.5, 0 ≤ d2 ≤ 0.5, 0 ≤ d3 ≤ 0.5, 0 ≤ d4 ≤ 0.5, 0 ≤ d5 ≤ 0.5, 0 ≤ d1 + d2 + d3 + d4 + d5 ≤ 0.5, 0 ≤ e ≤ 0.5, and 0 ≤ f ≤ 0.5; more preferably 0.05 ≤ a ≤ 0.7, 0 ≤ b1 ≤ 0.7, 0 ≤ b2 ≤ 0.7, 0 ≤ b1 + b2 ≤ 0.7, 0 ≤ c ≤ 0.8, 0 ≤ d1 ≤ 0.4, 0 ≤ d2 ≤ 0.4, 0 ≤ d3 ≤ 0.4, 0 ≤ d4 ≤ 0.4, 0 ≤ d5 ≤ 0.4, 0 ≤ d1 + d2 + d3 + d4 + d5 ≤ 0.4, 0 ≤ e ≤ 0.4, and 0 ≤ f ≤ 0.4; still more preferably 0.07 ≤ a ≤ 0.6, 0 ≤ b1 ≤ 0.6, 0 ≤ b2 ≤ 0.6, 0 ≤ b1 + b2 ≤ 0.6, 0 ≤ c ≤ 0.7, 0 ≤ d1 ≤ 0.3, 0 ≤ d2 ≤ 0.3, 0 ≤ d3 ≤ 0.3, 0 ≤ d4 ≤ 0.3, 0 ≤ d5 ≤ 0.3, 0 ≤ d1 + d2 + d3 + d4 + d5 ≤ 0.3, 0 ≤ e ≤ 0.3, and 0 ≤ f ≤ 0.3. However, a + b1 + b2 + c + d1 + d2 + d3 + d4 + d5 + e + f = 1.0.

[0260] To synthesize the base polymer, for example, monomers that provide the aforementioned repeating units may be heated in an organic solvent with the addition of a radical polymerization initiator to perform polymerization.

[0261] Examples of the organic solvent used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, dioxane, propylene glycol monomethyl ether, γ-butyrolactone, and mixed solvents thereof. Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide, and the like. The temperature during polymerization is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

[0262] When copolymerizing a monomer containing a hydroxy group, 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, or it may be substituted with an acetyl group, a formyl group, a pivaloyl group, etc., and then subjected to alkaline hydrolysis after polymerization.

[0263] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and the acetoxy group may be deprotected by the above-mentioned alkaline hydrolysis after polymerization to obtain hydroxystyrene or hydroxyvinylnaphthalene.

[0264] As the base for alkaline hydrolysis, aqueous ammonia, triethylamine, etc. can be used. The reaction temperature is preferably -20 to 100 °C, more preferably 0 to 60 °C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0265] The base polymer preferably has a polystyrene-equivalent weight average molecular weight (Mw) of 1000 to 500000, more preferably 2000 to 30000, as measured by gel permeation chromatography (GPC) using THF as a solvent. When Mw is within the above range, the heat resistance and solubility in an alkaline developer of the resist film are good.

[0266] Furthermore, when the molecular weight distribution (Mw / Mn) of the base polymer is broad, there are low molecular weight and high molecular weight polymers, so there is a risk that foreign substances will be seen on the pattern or the shape of the pattern will deteriorate after exposure. As the pattern rules become finer, the influence of Mw and Mw / Mn tends to increase. Therefore, in order to obtain a positive resist material that is suitably used for fine pattern dimensions, the Mw / Mn of the base polymer is preferably narrowly dispersed at 1.0 to 2.0, particularly 1.0 to 1.5.

[0267] To obtain a narrowly dispersed polymer, not only ordinary radical polymerization but also living radical polymerization can be used. Examples of living radical polymerization include nitroxide-mediated radical polymerization (NMP), atom transfer radical polymerization (ATRP), and reversible addition-fragmentation chain transfer (RAFT) polymerization.

[0268] The base polymer may contain two or more polymers having different composition ratios, Mw, and Mw / Mn. Further, a polymer containing the repeating unit a and a polymer not containing the repeating unit a may be blended.

[0269] [Organic solvent] The positive resist material of the present invention may contain an organic solvent. The organic solvent is not particularly limited as long as it can dissolve each of the above-described components and each of the components described below. Specific examples of the organic solvent include those described in paragraphs

[0144] to

[0145] of JP-A-2008-111103, such as ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as γ-butyrolactone, and the like.

[0270] In the positive resist material of the present invention, the content of the organic solvent is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass, per 100 parts by mass of the base polymer. The organic solvent may be used alone or in combination of two or more.

[0271] [Acid generator] The positive resist material of the present invention may contain an acid generator that generates a strong acid (hereinafter, also referred to as an additive acid generator). The strong acid referred to here means a compound having an acidity sufficient to cause a deprotection reaction of the acid-labile group of the base polymer.

[0272] Examples of the acid generator include compounds (photoacid generators) that generate an acid upon exposure to actinic rays or radiation. Any compound that generates an acid upon irradiation with high-energy rays may be used as the photoacid generator, but those that generate sulfonic acid, imidic acid, or methidic acid are preferred. Preferred photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, and the like. Specific examples of the photoacid generator include those described in paragraphs

[0122] to

[0142] of JP-A-2008-111103.

[0273] Also, as the photoacid generator, a sulfonium salt represented by the following formula (1-1) or an iodonium salt represented by the following formula (1-2) can also be preferably used. [Chemical formula]

[0274] In formulas (1-1) and (1-2), R 101 ~R 105 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like. The hydrocarbyl group may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples thereof include the same as those exemplified as the hydrocarbyl group represented by R 41 ~R 45 in the descriptions of formulas (M1) and (M2). Further, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and -CH of the hydrocarbyl group 2- may be partially substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. Further, R 101 and R 102 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. At this time, specific examples of the ring include the same ones as those exemplified as the rings that R 41 and R 42 may form together with the sulfur atom to which they are bonded in the description of formula (M1).

[0275] Specific examples of the cation of the sulfonium salt represented by formula (1-1) include the same ones as those exemplified as the sulfonium cation represented by formula (M1). Specific examples of the cation of the iodonium salt represented by formula (1-2) include the same ones as those exemplified as the iodonium cation represented by formula (M2).

[0276] In formulas (1-1) and (1-2), Xa - is an anion selected from the following formulas (1A) to (1D).

Chemical formula

[0277] In formula (1A), R fa is a fluorine atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same ones as those exemplified as the hydrocarbyl group represented by R fa1 in formula (1A') described later.

[0278] As the anion represented by formula (1A), the one represented by the following formula (1A') is preferable. [Chemical formula]

[0279] In formula (1A'), R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R fa1 is a hydrocarbyl group having 1 to 38 carbon atoms which may contain a heteroatom. As the heteroatom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc. are preferable, and an oxygen atom is more preferable. As the hydrocarbyl group, those having 6 to 30 carbon atoms are particularly preferable from the viewpoint of obtaining high resolution in fine pattern formation.

[0280] R fa1 The hydrocarbyl group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 38 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, 2-ethylhexyl group, nonyl group, undecyl group, tridecyl group, pentadecyl group, heptadecyl group, icosyl group; cyclic saturated hydrocarbyl groups having 3 to 38 carbon atoms such as cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, 1-adamantylmethyl group, norbornyl group, norbornylmethyl group, tricyclodecanyl group, tetracyclododecanyl group, tetracyclododecanylmethyl group, dicyclohexylmethyl group; unsaturated aliphatic hydrocarbyl groups having 2 to 38 carbon atoms such as allyl group, 3-cyclohexenyl group; aryl groups having 6 to 38 carbon atoms such as phenyl group, 1-naphthyl group, 2-naphthyl group; aralkyl groups having 7 to 38 carbon atoms such as benzyl group, diphenylmethyl group; groups obtained by combining these, and the like.

[0281] Further, 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, a halogen atom, etc., and the -CH of the hydrocarbyl group2 Part of the "-" may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. Specific examples of the hydrocarbyl group containing a heteroatom include a tetrahydrofuryl group, a methoxymethyl group, an ethoxymethyl group, a methylthiomethyl group, an acetamidomethyl group, a trifluoroethyl group, a (2-methoxyethoxy)methyl group, an acetoxymethyl group, a 2-carboxy-1-cyclohexyl group, a 2-oxopropyl group, a 4-oxo-1-adamantyl group, a 3-oxocyclohexyl group, etc.

[0282] Regarding the synthesis of the sulfonium salt containing the anion represented by the formula (1A'), it is detailed in JP-A-2007-145797, JP-A-2008-106045, JP-A-2009-7327, JP-A-2009-258695, etc. Further, the sulfonium salts described in JP-A-2010-215608, JP-A-2012-41320, JP-A-2012-106986, JP-A-2012-153644, etc. are also preferably used.

[0283] Specific examples of the anion represented by the formula (1A) include those similar to those exemplified as the anion represented by the formula (1A) in JP-A-2018-197853.

[0284] In the formula (1B), R fb1 and R fb2 are each independently a fluorine atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those similar to those exemplified as the hydrocarbyl group represented by R fa1 in the formula (1A'). R fb1 and R fb2Preferably, it is a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. Also, R fb1 and R fb2 may be bonded to each other to form a ring together with the group (-CF 2 -SO 2 -N - -SO 2 -CF 2 -) to which they are bonded. At this time, the group obtained by bonding R fb1 and R fb2 to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0285] In formula (1C), R fc1 , R fc2 and R fc3 are each independently a fluorine atom or a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include the same ones as those exemplified as the hydrocarbyl group represented by R fa1 in formula (1A'). Preferably, R fc1 , R fc2 and R fc3 are a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. Also, R fc1 and R fc2 may be bonded to each other to form a ring together with the group (-CF 2 -SO 2 -C - -SO 2 -CF 2 -) to which they are bonded. At this time, the group obtained by bonding R fc1 and R fc2 to each other is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0286] In formula (1D), R fd is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include the same ones as those of R fa1 in formula (1A'). in formula (1A').Examples thereof include the same ones as those exemplified as the hydrocarbyl group represented by

[0287] Regarding the synthesis of the sulfonium salt containing the anion represented by formula (1D), it is detailed in JP-A-2010-215608 and JP-A-2014-133723.

[0288] Specific examples of the anion represented by formula (1D) include the same ones as those exemplified as the anion represented by formula (1D) in JP-A-2018-197853.

[0289] Note that the photoacid generator containing the anion represented by formula (1D) does not have a fluorine atom at the α-position of the sulfo group, but has two trifluoromethyl groups at the β-position, and thus has sufficient acidity to cleave the acid-labile group in the base polymer. Therefore, it can be used as a photoacid generator.

[0290] As the photoacid generator, the one represented by the following formula (2) can also be preferably used.

Chemical formula

[0291] In formula (2), R 201 and R 202 are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a hetero atom. R 203 is a hydrocarbylene group having 1 to 30 carbon atoms which may contain a hetero atom. Further, any two of R 201 , R 202 and R 203 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. At this time, specific examples of the ring include the same ones as those exemplified as the ring that can be formed together with the sulfur atom to which R 2 and R 3 are bonded in the description of formula (a).

[0292] R201 and R 202 The hydrocarbyl group represented by may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, tert-pentyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group; cyclopentyl group, cyclohexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylbutyl group, norbornyl group, tricyclo[5.2.1.0 2,6 decyl group, adamantyl group and other cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms; aryl groups having 6 to 30 carbon atoms such as phenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, isopropylphenyl group, n-butylphenyl group, isobutylphenyl group, sec-butylphenyl group, tert-butylphenyl group, naphthyl group, methylnaphthyl group, ethylnaphthyl group, n-propylnaphthyl group, isopropylnaphthyl group, n-butylnaphthyl group, isobutylnaphthyl group, sec-butylnaphthyl group, tert-butylnaphthyl group, anthracenyl group; groups obtained by combining these and the like. Further, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of -CH 2 - of the hydrocarbyl group may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, it may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0293] R 203The hydrocarbylene group represented by 2 - may be saturated or unsaturated and may be linear, branched, or cyclic. Specific examples thereof include alkanediyl groups having 1 to 30 carbon atoms such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group; cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, adamantanediyl group; arylene groups having 6 to 30 carbon atoms such as phenylene group, methylphenylene group, ethylphenylene group, n-propylphenylene group, isopropylphenylene group, n-butylphenylene group, isobutylphenylene group, sec-butylphenylene group, tert-butylphenylene group, naphthylene group, methylnaphthylene group, ethylnaphthylene group, n-propylnaphthylene group, isopropylnaphthylene group, n-butylnaphthylene group, isobutylnaphthylene group, sec-butylnaphthylene group, tert-butylnaphthylene group; groups obtained by combining these, and the like. Further, some or all of the hydrogen atoms of the hydrocarbylene 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 a part of 2 -CH of the hydrocarbylene 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, it may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, or the like. As the heteroatom, an oxygen atom is preferred.

[0294] In formula (2), L C is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a single bond, an ether bond, or a hetero atom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those similar to the hydrocarbylene groups exemplified as the R 203 represented ones.

[0295] In formula (2), X A , X B , X C and X D are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. However, at least one of X A , X B , X C and X D is a fluorine atom or a trifluoromethyl group.

[0296] In formula (2), k is an integer from 0 to 3.

[0297] As the photoacid generator represented by formula (2), those represented by the following formula (2') are preferable.

Chemical formula

[0298] In formula (2'), L C is the same as described above. X E is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R 301 , R 302 and R 303 are each independently a hydrogen atom, or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those similar to the hydrocarbyl groups exemplified as the R fa1 represented in formula (1A'). k1 and k2 are each independently an integer from 0 to 5, and k3 is an integer from 0 to 4.

[0299] Specific examples of the photoacid generator represented by formula (2) include those similar to those exemplified as the photoacid generator represented by formula (2) in JP-A-2017-026980.

[0300] Among the above photoacid generators, those containing an anion represented by formula (1A') or (1D) are particularly preferred because they have low acid diffusion and excellent solubility in solvents. In addition, those represented by formula (2') are particularly preferred because they have extremely low acid diffusion.

[0301] As the photoacid generator, a sulfonium salt or an iodonium salt containing an anion having an aromatic ring substituted with an iodine atom or a bromine atom can also be used. Specific examples of such salts include those represented by the following formula (3-1) or (3-2).

Chemical formula

[0302] In formulas (3-1) and (3-2), p is an integer satisfying 1 ≤ p ≤ 3. q and r are integers satisfying 1 ≤ q ≤ 5, 0 ≤ r ≤ 3, and 1 ≤ q + r ≤ 5. q is preferably an integer satisfying 1 ≤ q ≤ 3, more preferably 2 or 3. r is preferably an integer satisfying 0 ≤ r ≤ 2.

[0303] In formulas (3-1) and (3-2), X BI is an iodine atom or a bromine atom, and when p and / or q is 2 or more, they may be the same as or different from each other.

[0304] In formulas (3-1) and (3-2), 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.

[0305] In formulas (3-1) and (3-2), L 12When p is 1, it is a single bond or a divalent linking group having 1 to 20 carbon atoms, and when p is 2 or 3, it is a (p + 1)-valent linking group having 1 to 20 carbon atoms, and the linking group may contain an oxygen atom, a sulfur atom or a nitrogen atom.

[0306] In formulas (3-1) and (3-2), R 401 is a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a 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 a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group or an ether bond, or -N(R 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D or -N(R 401C )-C(=O)-O-R 401D . R 401A and R 401B are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 401C is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. R 401Dis an aliphatic hydrocarbyl group having 1 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aralkyl group having 7 to 15 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. The aliphatic hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group, hydrocarbyloxy group, hydrocarbylcarbonyl group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When p and / or r is 2 or more, each R 401 may be the same as or different from each other.

[0307] Among these, R 401 is preferably a hydroxy group, -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-O-R 401D , a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group, or the like.

[0308] In formulas (3-1) and (3-2), Rf 11 ~Rf 14 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, and at least one of these is a fluorine atom or a trifluoromethyl group. Further, Rf 11 and Rf 12 may combine to form a carbonyl group. In particular, it is preferable that both Rf 13 and Rf 14 are fluorine atoms.

[0309] In formulas (3-1) and (3-2), R 402 ~R 406is independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a hetero atom. Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include those similar to those exemplified as the hydrocarbyl group represented by R 2 ~R 4 in the description of formula (a). Further, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone ring, a sulfo group or a sulfonium salt-containing group, and a part of -CH 2 - of the hydrocarbyl group may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond or a sulfonic acid ester bond. Further, R 402 and R 403 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. At this time, specific examples of the ring include those similar to those exemplified as the ring that can be formed by R 41 and R 42 bonded to each other together with the sulfur atom to which they are bonded in the description of formula (M1).

[0310] Specific examples of the cation of the sulfonium salt represented by formula (3-1) include those similar to those exemplified as the sulfonium cation represented by M + in the description of formulas (d2) to (d5). Further, specific examples of the cation of the iodonium salt represented by formula (3-2) include those similar to those exemplified as the iodonium cation represented by M + in the description of formulas (d2) to (d5).

[0311] Specific examples of the anion of the onium salt represented by formula (3-1) or (3-2) include those similar to those exemplified as the anion represented by formula (d1-3).

[0312] As the photoacid generator, a sulfonium salt or iodonium salt of fluorobenzenesulfonic acid combined with iodobenzoic acid represented by the following formula (3-3) or (3-4) can also be used.

Chemical formula

[0313] In formulas (3-3) and (3-4), s is an integer from 1 to 5. t is an integer from 0 to 3. u is an integer from 1 to 4.

[0314] In formulas (3-3) and (3-4), R 411 is a hydroxy group, a carboxy group, an alkoxycarbonyl group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, or a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, which may contain a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group, or an alkoxy group, or -N(R 411A )-C(=O)-R 411B or -N(R 411A )-C(=O)-O-R 411B . R 411A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 411B 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, which 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.

[0315] In formulas (3-3) and (3-4), L 3 is a single bond or a divalent linking group having 1 to 20 carbon atoms, and the linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

[0316] In formulas (3-3) and (3-4), Rf 21 is a fluorine atom or a trifluoromethyl group.

[0317] In formulas (3-3) and (3-4), R 412 ~R 416 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include those exemplified as the hydrocarbyl group represented by R 2 ~R 4 in the description of formula (a). Further, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone ring, a sulfo group or a sulfonium salt-containing group, and a part of -CH 2 - of the hydrocarbyl group may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond or a sulfonate ester bond. Furthermore, R 402 and R 403 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. At this time, specific examples of the ring include those similar to those exemplified as the ring that can be formed together with the sulfur atom to which R 2 and R 3 are bonded in the description of formula (a).

[0318] Specific examples of the cation of the sulfonium salt represented by formula (3-3) include those similar to those exemplified as the sulfonium cation represented by M + in the description of formulas (d2) to (d5). Further, specific examples of the cation of the iodonium salt represented by formula (3-4) include those similar to those exemplified as the iodonium cation represented by M + in the description of formulas (d2) to (d5).

[0319] Specific examples of the anion of the onium salt represented by formula (3-3) or (3-4) include, but are not limited to, those shown below. [Chemical formula]

[0320] [Chemical formula]

[0321] [Chemical formula]

[0322] [Chemical formula]

[0323] [Chemical formula]

[0324] When the positive resist material of the present invention contains the additive acid generator, its content is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, based on 100 parts by mass of the base polymer. The additive acid generator may be used alone or in combination of two or more. The positive resist material of the present invention can function as a chemically amplified positive resist material by containing any of the repeating units d1 to d5 in the base polymer and / or by containing an additive acid generator.

[0325] [Quencher] The positive resist material of the present invention may contain a quencher. The quencher means a compound that can prevent the diffusion to the unexposed part by trapping the acid generated from the acid generator in the resist material.

[0326] Examples of the quencher include conventional basic compounds. Specific examples of the 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, carbamates, and the like. In particular, the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonic acid ester bond, or compounds having a carbamate bond described in Japanese Patent No. 3,790,649 are preferable. By adding such a basic compound, for example, the acid diffusion rate in the resist film can be further suppressed, or the shape can be corrected.

[0327] In addition, examples of the quencher include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids, carboxylic acids, or fluorinated alkoxides in which the α-position is not fluorinated, as described in JP-A-2008-158339. Sulfonic acids, imidic acids, or methidic acids in which the α-position is fluorinated are necessary for deprotecting the acid-labile group of the carboxylic acid ester, but sulfonic acids, carboxylic acids, or fluorinated alcohols in which the α-position is not fluorinated are released by salt exchange with the onium salt. Sulfonic acids, carboxylic acids, and fluorinated alcohols in which the α-position is not fluorinated do not cause a deprotection reaction and thus function as a quencher.

[0328] Specific examples of such a quencher include, for example, a compound represented by the following formula (4) (onium salt of a sulfonic acid in which the α-position is not fluorinated), a compound represented by the following formula (5) (onium salt of a carboxylic acid), and a compound represented by the following formula (6) (onium salt of an alkoxide).

Chemical formula

[0329] In formula (4), R 501 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hydrogen atom or a hetero atom, provided that the hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is excluded from those substituted with a fluorine atom or a fluoroalkyl group.

[0330] R 501 The hydrocarbyl group having 1 to 40 carbon atoms represented by 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 methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, tert-pentyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group; cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms such as cyclopentyl group, cyclohexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylbutyl group, norbornyl group, tricyclo[5.2.1.0 2,6 decyl group, adamantyl group, adamantylmethyl group; alkenyl groups having 2 to 40 carbon atoms such as vinyl group, allyl group, propenyl group, butenyl group, hexenyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 40 carbon atoms such as cyclohexenyl group; aryl groups having 6 to 40 carbon atoms such as phenyl group, naphthyl group, alkylphenyl group (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-n-butylphenyl group, etc.), di- or trialkylphenyl group (2,4-dimethylphenyl group, 2,4,6-triisopropylphenyl group, etc.), alkylnaphthyl group (methylnaphthyl group, ethylnaphthyl group, etc.), dialkylnaphthyl group (dimethylnaphthyl group, diethylnaphthyl group, etc.); aralkyl groups having 7 to 40 carbon atoms such as benzyl group, 1-phenylethyl group, 2-phenylethyl group, etc.

[0331] Further, 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 the -CH 2 - part 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. As a result, it may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=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; aryloxoalkyl groups such as a 2-aryl-2-oxoethyl group such as a 2-phenyl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, and a 2-(2-naphthyl)-2-oxoethyl group, etc.

[0332] In formula (5), R 502 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. Specific examples of the hydrocarbyl group represented by R 502 include the same ones as those exemplified as the hydrocarbyl group represented by R 101 In addition, 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; fluorinated aryl groups such as a pentafluorophenyl group and a 4-trifluoromethylphenyl group, etc.

[0333] In formula (6), R 503is a saturated hydrocarbyl group having 1 to 8 carbon atoms and at least 3 fluorine atoms or an aryl group having 6 to 10 carbon atoms and at least 3 fluorine atoms, and may contain a nitro group.

[0334] In formulas (4), (5) and (6), Mq + is an onium cation. As the onium cation, a sulfonium cation, an iodonium cation or an ammonium cation is preferable, and a sulfonium cation is more preferable. Specific examples of the sulfonium cation include those similar to those exemplified as the sulfonium cation represented by M + in the description of formulas (d2) to (d5).

[0335] As the quencher, a sulfonium salt of an iodinated benzene ring-containing carboxylic acid represented by the following formula (7) can also be preferably used.

Chemical formula

[0336] 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.

[0337] In formula (7), R 511 is 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 part or all of the hydrogen atoms may be substituted with halogen atoms, or -N(R 511A )-C(=O)-R 511B or -N(R 511A )-C(=O)-O-R 511B is. R 511A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 511Bis 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 511 may be the same as or different from each other.

[0338] In formula (7), L 21 is a single bond or a (z + 1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one 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.

[0339] In formula (7), R 512 , R 513 and R 514 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same ones as those exemplified as the hydrocarbyl groups represented by R 41 ~R 45 in the description of formulas (M1) and (M2).

[0340] Specific examples of the cation of the sulfonium salt represented by (7) include the same ones as those exemplified as the sulfonium cation represented by M + in the description of formulas (d2) to (d5).

[0341] Specific examples of the sulfonium salt represented by formula (7) include those described in JP-A-2017-219836 and JP-A-2021-91666.

[0342] As another example of the quencher, a polymer type quencher described in JP-A-2008-239918 can be mentioned. This enhances the rectangularity of the resist pattern by orienting on the resist film surface. The polymer type quencher also has the effect of preventing film loss of the pattern and rounding of the pattern top when a protective film for immersion exposure is applied.

[0343] Furthermore, a betaine type sulfonium salt described in Japanese Patent No. 6848776 and JP-A-2020-37544, a methide acid containing no fluorine atom described in JP-A-2020-55797, a sulfonium salt of sulfonamide described in Japanese Patent No. 5807552, a sulfonium salt of sulfonamide containing an iodine atom described in JP-A-2019-211751, phenol, a halogen, or an acid generator that generates carbonic acid can also be used as the quencher.

[0344] When the positive resist material of the present invention contains the quencher, its content is preferably 0 to 5 parts by mass, more preferably 0 to 4 parts by mass, based on 100 parts by mass of the base polymer. The quencher may be used alone or in combination of two or more.

[0345] [Other Components] In addition to the components described above, the positive resist material of the present invention may contain a surfactant, a dissolution inhibitor, a water repellency improver, acetylene alcohols, and the like.

[0346] Specific examples of the surfactant include those described in paragraphs

[0165] to

[0166] of JP-A-2008-111103. By adding a surfactant, the coatability of the resist material can be further improved or controlled. When the positive resist material of the present invention contains a surfactant, its content is preferably 0.0001 to 10 parts by mass based on 100 parts by mass of the base polymer. The surfactant may be used alone or in combination of two or more.

[0347] The positive resist material of the present invention can further increase the difference in dissolution rate between the exposed portion and the unexposed portion by blending a dissolution inhibitor, and can further improve the resolution. Specific examples of the dissolution inhibitor include a compound having a molecular weight preferably of 100 to 1000, more preferably 150 to 800, and containing two or more phenolic hydroxy groups in the molecule, and the hydrogen atoms of the phenolic hydroxy groups are substituted as a whole by acid-labile groups at a ratio of 0 to 100 mol%, or a compound having a carboxy group in the molecule, and the hydrogen atoms of the carboxy groups are substituted as a whole by acid-labile groups at an average ratio of 50 to 100 mol%. Specifically, compounds in which the hydrogen atoms of the hydroxy groups and carboxy groups of bisphenol A, trisphenol, phenolphthalein, cresol novolak, naphthalene carboxylic acid, adamantane carboxylic acid, and cholic acid are substituted with acid-labile groups, etc. can be mentioned. For example, they are described in paragraphs

[0155] to

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

[0348] When the positive resist material of the present invention contains the dissolution inhibitor, its content is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass, based on 100 parts by mass of the base polymer. The dissolution inhibitor may be used alone or in combination of two or more.

[0349] The water repellency improver improves the water repellency of the resist film surface and can be used in immersion lithography without using a top coat. As the water repellency improver, a polymer containing an alkyl fluoride group, a polymer containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue having a specific structure, etc. are preferable, and those exemplified in JP-A-2007-297590, JP-A-2008-111103, etc. are preferable. The water repellency improver needs to be soluble in an alkaline developer or an organic solvent developer. The water repellency improver having the above-described specific 1,1,1,3,3,3-hexafluoro-2-propanol residue has good solubility in the developer. As the water repellency improver, a polymer containing a repeating unit containing an amino group or an amine salt has a high effect of preventing the evaporation of the acid in the PEB and preventing the opening failure of the hole pattern after development. When the positive resist material of the present invention contains the water repellency improver, its content is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the base polymer. The water repellency improver may be used alone or in combination of two or more types.

[0350] Specific examples of the acetylene alcohols include those described in paragraphs

[0179] to

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

[0351] [Pattern formation method] When the positive resist material of the present invention is used for manufacturing various integrated circuits, known lithography techniques can be applied. For example, as a pattern formation method, a method including a step of forming a resist film on a substrate using the above-described positive resist material, a step of exposing the resist film with high energy rays, and a step of developing the exposed resist film using a developer can be mentioned.

[0352] First, the positive resist material of the present invention is applied onto a substrate for integrated circuit manufacturing (Si, SiO 2 , SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflection film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi 2 , SiO 2 , etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc. so that the coating film thickness becomes 0.01 to 2 μm. This is 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.

[0353] Next, the resist film is exposed using high-energy rays. Specific examples of the high-energy rays include ultraviolet rays, far ultraviolet rays, EB, EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, γ-rays, synchrotron radiation, etc. When using ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer laser light, γ-rays, synchrotron radiation, etc. as the high-energy rays, the exposure amount is preferably about 1 to 200 mJ / cm 2 , more preferably about 10 to 100 mJ / cm 2 , and irradiation is performed so as to be in this range. When using EB as the high-energy ray, the exposure amount is preferably about 0.1 to 300 μC / cm 2 , more preferably about 0.5 to 200 μC / cm 2 , and drawing is performed directly or using a mask for forming a target pattern. Note that the positive resist material of the present invention is particularly suitable for fine patterning by KrF excimer laser light, ArF excimer laser light, EB, EUV, X-rays, soft X-rays, γ-rays, synchrotron radiation among high-energy rays, and is particularly suitable for fine patterning by EB or EUV.

[0354] After exposure, PEB may or may not be performed on a hot plate or in an oven, preferably at 30 to 150 °C for 10 seconds to 30 minutes, more preferably at 50 to 120 °C for 30 seconds to 20 minutes.

[0355] After exposure or after PEB, a developer of an alkaline aqueous solution such as 0.1 to 10% by mass, preferably 2 to 5% by mass of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc. is used, and the resist film exposed by a conventional method such as dip method, puddle method, spray method, etc. for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes is developed. Thus, the irradiated part is dissolved in the developer, the unexposed part is not dissolved, and the target pattern is formed on the substrate.

[0356] Using a positive resist material containing a base polymer containing an acid-labile group, a negative pattern can also be obtained by organic solvent development. Specific examples of the developer used at this time include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents may be used alone or in combination of two or more.

[0357] At the end of development, rinsing is performed. As the rinsing liquid, a solvent that is miscible with the developer and does not dissolve the resist film is preferred. As such a solvent, alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms are preferably used.

[0358] Specific examples of the alcohol having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, and the like.

[0359] Specific examples of the ether compound having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, di-n-hexyl ether, and the like.

[0360] Specific examples of the alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. Specific examples of the alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Specific examples of the alkynes having 6 to 12 carbon atoms include hexyne, heptyne, octyne, etc.

[0361] Specific examples of the aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, mesitylene, etc.

[0362] By performing rinsing, it is possible to reduce the occurrence of resist pattern collapse and defects. Also, rinsing is not necessarily essential, and the amount of solvent used can be reduced by not performing rinsing.

[0363] The hole pattern and trench pattern after development can also be shrunk by thermal flow, RELACS technology or DSA technology. A shrinking agent is applied onto the hole pattern, and crosslinking of the shrinking agent occurs on the surface of the resist film due to diffusion of the acid catalyst from the resist film during baking, and the shrinking agent adheres to the sidewalls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds, to remove the excess shrinking agent and shrink the hole pattern.

Examples

[0364] Hereinafter, synthesis examples, examples and comparative examples will be shown to specifically explain the present invention, but the present invention is not limited to the following examples.

[0365] [1] Synthesis of Polymer The acid-labile group-protected vinyl salicylic acid-based monomers a-1 to a-8, acid-labile group-containing monomers ALG-1 and ALG-2, and acid generator-containing monomers PM-1 to PM-12 used in the synthesis of the polymer are as follows. The Mw of the polymer is the polystyrene-equivalent measurement value by GPC using THF as the solvent. [Chemical formula]

[0366] [Chemical formula]

[0367] [Chemical formula]

[0368] [Chemical formula]

[0369] [Synthesis Example 1] Synthesis of Polymer P-1 To a 2 L flask, 4.2 g of monomer a-1, 5.9 g of 1-methyl-1-cyclopentyl methacrylate, 6.0 g of 3-hydroxystyrene, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the mixture was reacted for 15 hours. The reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain Polymer P-1. The composition of Polymer P-1 was 13 confirmed by C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical formula]

[0370] [Synthesis Example 2] Synthesis of Polymer P-2 4.2 g of monomer a-1, 8.8 g of ALG-1, 5.4 g of 4-hydroxystyrene, and 40 g of THF as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the reaction was carried out for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain polymer P-2. The composition of polymer P-2 was 13 confirmed by C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical formula]

[0371] [Synthesis Example 3] Synthesis of Polymer P-3 6.1 g of monomer a-2, 5.9 g of 1-methyl-1-cyclopentyl methacrylate, 4.8 g of 3-hydroxystyrene, 8.5 g of monomer PM-1, and 40 g of THF as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the reaction was carried out for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain polymer P-3. The composition of polymer P-3 was 13 confirmed by C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical formula]

[0372] [Synthesis Example 4] Synthesis of Polymer P-4 To a 2 L flask, 3.1 g of monomer a-3, 7.6 g of 1-methyl-1-cyclopentyl methacrylate, 4.2 g of 3-hydroxystyrene, 9.7 g of monomer PM-2, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the reaction was carried out for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain polymer P-4. The composition of polymer P-4 was 13 determined by C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical Formula]

[0373] [Synthesis Example 5] Synthesis of Polymer P-5 To a 2 L flask, 4.4 g of monomer a-4, 4.1 g of 1-methyl-1-cyclopentyl methacrylate, 4.8 g of 4-hydroxystyrene, 10.9 g of monomer PM-3, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the reaction was carried out for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain polymer P-5. The composition of polymer P-5 was 13 determined by C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical Formula]

[0374] [Synthesis Example 6] Synthesis of Polymer P-6 To a 2 L flask, 6.1 g of monomer a-5, 7.8 g of monomer ALG-2, 4.8 g of 4-hydroxystyrene, 10.6 g of monomer PM-4, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the reaction was carried out for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain polymer P-6. The composition of polymer P-6 was 13 C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical formula]

[0375] [Synthesis Example 7] Synthesis of Polymer P-7 To a 2 L flask, 4.4 g of monomer a-6, 5.9 g of 1-methyl-1-cyclopentyl methacrylate, 4.8 g of 4-hydroxystyrene, 12.2 g of monomer PM-5, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the reaction was carried out for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain polymer P-7. The composition of polymer P-7 was 13 C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical formula]

[0376] [Synthesis Example 8] Synthesis of Polymer P-8 To a 2 L flask, 3.4 g of monomer a-7, 8.9 g of monomer ALG-1, 4.8 g of 4-hydroxystyrene, 11.0 g of monomer PM-6, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the reaction was carried out for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain polymer P-8. The composition of polymer P-8 was 13 C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical formula]

[0377] [Synthesis Example 9] Synthesis of Polymer P-9 To a 2 L flask, 2.9 g of monomer a-8, 7.1 g of 1-ethynyl-1-cyclopentyl methacrylate, 4.8 g of 3-hydroxystyrene, 11.2 g of monomer PM-7, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the reaction was carried out for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain polymer P-9. The composition of polymer P-9 was 13 C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical formula]

[0378] [Synthesis Example 10] Synthesis of Polymer P-10 4.2 g of monomer a-1, 6.2 g of 1-ethynyl-1-cyclopentyl methacrylate, 4.8 g of 3-hydroxystyrene, 10.0 g of monomer PM-8, and 40 g of THF as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the mixture was reacted for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain polymer P-10. The composition of polymer P-10 was 13 C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical Formula]

[0379] [Synthesis Example 11] Synthesis of Polymer P-11 4.2 g of monomer a-1, 7.8 g of monomer ALG-2, 4.8 g of 3-hydroxystyrene, 11.0 g of monomer PM-9, and 40 g of THF as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the mixture was reacted for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain polymer P-11. The composition of polymer P-11 was 13 C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical Formula]

[0380] [Synthesis Example 12] Synthesis of Polymer P-12 Into a 2 L flask, 12.5 g of monomer a-1, 6.6 g of 3-hydroxystyrene, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the reaction was carried out for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain polymer P-12. The composition of polymer P-12 was 13 C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical formula]

[0381] [Synthesis Example 13] Synthesis of Polymer P-13 Into a 2 L flask, 4.2 g of monomer a-1, 7.8 g of monomer ALG-2, 4.8 g of 3-hydroxystyrene, 13.8 g of monomer PM-10, and 40 g of THF as a solvent were added. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the reaction was carried out for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain polymer P-13. The composition of polymer P-13 was 13 C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical formula]

[0382] [Synthesis Example 14] Synthesis of Polymer P-14 4.2 g of monomer a-1, 7.8 g of monomer ALG-2, 4.8 g of 3-hydroxystyrene, 11.2 g of monomer PM-11, and 40 g of THF as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the mixture was reacted for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain polymer P-14. The composition of polymer P-14 was 13 confirmed by C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical formula]

[0383] [Synthesis Example 15] Synthesis of Polymer P-15 4.2 g of monomer a-1, 7.8 g of monomer ALG-2, 4.8 g of 3-hydroxystyrene, 10.2 g of monomer PM-12, and 40 g of THF as a solvent were added to a 2 L flask. The reaction vessel was cooled to -70 °C under a nitrogen atmosphere, and degassing under reduced pressure and nitrogen blowing were repeated three times. After warming to room temperature, 1.2 g of AIBN was added as a polymerization initiator, the temperature was raised to 60 °C, and the mixture was reacted for 15 hours. This reaction solution was added to 1 L of isopropyl alcohol, and the precipitated white solid was filtered off. The obtained white solid was dried under reduced pressure at 60 °C to obtain polymer P-15. The composition of polymer P-15 was 13 confirmed by C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical formula]

[0384] [Comparative Synthesis Example 1] Synthesis of Comparative Polymer cP-1 A comparative polymer cP-1 was obtained in the same manner as in Synthesis Example 1 except that monomer a-1 was not used. The composition of comparative polymer cP-1 was 13C-NMR and 1 The Mw and Mw / Mn were confirmed by GPC through 1H-NMR. [Chemical formula]

[0385] [Examples 1 to 15, Comparative Example 1] In a solvent in which 50 ppm of the surfactant PolyFox PF-636 manufactured by Omnova was dissolved, a solution in which each component was dissolved with the composition shown in Table 1 was filtered through a 0.2-μm size filter to prepare a positive resist material.

[0386] In Table 1, each component is as follows. · Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (diacetone alcohol) EL (ethyl lactate)

[0387] · Acid generator: PAG-1, PAG-2 [Chemical formula]

[0388] · Quencher: Q-1 [Chemical formula]

[0389] (2) EUV lithography evaluation Each positive resist material shown in Table 1 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content: 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed to a film thickness of 20 nm, and pre-baked at 105°C for 60 seconds using a hot plate to produce a positive resist film with a film thickness of 40 nm. The resist film was exposed using an EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.7, dipole illumination) manufactured by ASML, PEB was performed on a hot plate at the temperature shown in Table 1 for 60 seconds, and development was carried out for 30 seconds with a 2.38% by mass TMAH aqueous solution to form a line and space with a pitch of 32 nm and a line width of 16 nm. Using a length measurement SEM (CG6300) manufactured by Hitachi High-Tech Corporation, the exposure dose at which a line pattern was formed with a dimension of 16 nm ± 1.6 nm was determined, and the line edge roughness (LWR) of the line at this exposure dose was measured. The wafer was cleaved, and the cross-section of the 16 nm line and space pattern was observed with an SEM (S-4800) manufactured by Hitachi High-Tech Corporation to observe the presence or absence of undercut in the space portion. The results are shown in Table 1.

[0390]

Table 1

[0391] From the results shown in Table 1, it was found that the positive resist material of the present invention containing a polymer containing a repeating unit a represented by the formula (a) has sufficient sensitivity and satisfies the effects of reducing LWR and undercut in the space portion.

Claims

1. A positive resist material comprising a base polymer containing a repeating unit a represented by the following formula (a): 【Chemistry 1】 (In the formula, m is 0 or 1, and n is an integer from 0 to 4. R A is a hydrogen atom or a methyl group. X 1 is a single bond or an ester bond. X 2 is a single bond, a saturated hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group. X 3 is a single bond, an ester bond, an ether bond or a carbonyl group. R 1 represents a hydrocarbyl group having 1 to 8 carbon atoms, a hydroxy group, a hydrocarbyloxy group having 1 to 8 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms, a hydrocarbyloxycarbonyloxy group having 2 to 8 carbon atoms, or a halogen atom. R 2 and R 3 are each independently a single bond, a methylene group, an ethylene group, a propylene group, or a butylene group, and may be substituted with a halogen atom. 2 and R 3 cannot simultaneously be a single bond. Ring R is a benzene ring or a naphthalene ring, which may be substituted with a hydrocarbyl group having 1 to 8 carbon atoms, a hydroxy group, a hydrocarbyloxy group having 1 to 8 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms, a hydrocarbyloxycarbonyloxy group having 2 to 8 carbon atoms, or a halogen atom. *1 and *2 represent bonds to the carbon atoms on the aromatic ring in the formula.)

2. 2. The positive resist material according to claim 1, wherein the base polymer further comprises a repeating unit b in which a hydrogen atom of a carboxy group or a phenolic hydroxy group is substituted with an acid labile group.

3. 3. The positive resist material according to claim 2, wherein the repeating unit b is at least one selected from the group consisting of a repeating unit b1 represented by the following formula (b1) and a repeating unit b2 represented by the following formula (b2): 【Chemistry 2】 (In the formula, R A are each independently a hydrogen atom or a methyl group. Y 1 represents a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 12 carbon atoms containing at least one bond selected from an ester bond, an ether bond and a lactone ring, and the phenylene group, naphthylene group and linking group may have at least one bond selected from a halogen atom, a nitro group, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms, and a saturated hydrocarbyloxycarbonyloxy group having 2 to 8 carbon atoms. Y 2 is a single bond, an ester bond or an amide bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 is an acid labile group. R 13 is a fluorine atom, a trifluoromethyl group, a cyano group, or an alkyl group having 1 to 6 carbon atoms. R 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the -CH 2 A part of the - may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer from 0 to 4, provided that 1≦a+b≦5. ）

4. 2. The positive resist material according to claim 1, wherein the base polymer further comprises a repeating unit c having an adhesive group selected from the group consisting of 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, -O-C(=O)-S-, and -O-C(=O)-NH-.

5. 2. The positive resist material according to claim 1, further comprising an organic solvent.

6. 2. The positive resist material according to claim 1, further comprising an acid generator.

7. 2. The positive resist material according to claim 1, further comprising a quencher.

8. 2. The positive resist material according to claim 1, further comprising a surfactant.

9. A pattern forming method comprising the steps of: forming a resist film on a substrate using the positive resist material according to any one of claims 1 to 8; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer.

10. 10. The method for forming a pattern according to claim 9, wherein the high energy beam is i-beam, KrF excimer laser beam, ArF excimer laser beam, electron beam or extreme ultraviolet ray having a wavelength of 3 to 15 nm.

Images