Positive resist material and patterning process

Abstract

To provide a positive resist material that exhibits higher sensitivity than conventional positive resist materials, reduced dimensional variation, and a favorable pattern profile after exposure, and also to provide a positive resist composition containing the material, a patterning method using the composition, and a polymer compound serving as the positive resist material.SOLUTION: The present invention provides a positive resist material comprising a base polymer having, as a pendant group bound to the polymer backbone, a sulfonium salt or an iodonium salt of a carboxylic acid, wherein the base polymer includes a repeating unit of a specific structure that includes a repeating unit (a) including one or more iodine atoms between the polymer backbone and the carboxylate.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 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 3nm node and sub-next-generation 2nm node 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 dimensional size of 45nm or less, it has been proposed that not only the improvement of the dissolution contrast conventionally proposed 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 significantly decrease.

[0004] The triangular trade-off relationship among sensitivity, resolution, and edge roughness 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 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 sulfonic acid is directly bonded to the main chain.

[0006] To suppress acid diffusion, a resist material of a polymer-bound quencher using a sulfonium salt of a weak acid having a polymerizable group and a pKa of -0.8 or more as a base polymer has been proposed (Patent Documents 3 to 5). In Patent Document 3, carboxylic acid, sulfonamide, phenol, hexafluoroalcohol, etc. are cited as weak acids.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Non-Patent Documents

[0008]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] The present invention has been made in view of the above circumstances, and provides a positive resist material having higher sensitivity than conventional positive resist materials, small dimensional variations, and a good pattern shape after exposure, a positive resist composition containing the resist material, a pattern forming method using the composition, and a polymer compound serving as the positive resist material.

Means for Solving the Problems

[0010] In order to solve the above problems, the present invention provides a positive resist material comprising a base polymer having a sulfonium salt or iodonium salt of a carboxylic acid bonded as a pendant group to a polymer main chain, wherein the base polymer contains a repeating unit a containing one or more iodine atoms between the polymer main chain and the carboxylate, and the repeating unit a contains either or both of a repeating unit represented by the following general formula (a)-1 and a repeating unit represented by (a)-2.

Chemical formula

[0011] Such a positive resist material serving as a base polymer has higher sensitivity than conventional resist materials, small dimensional variations, and a good pattern shape after exposure.

[0012] Further, in the present invention, it is preferably one containing at least one selected from repeating units represented by the following formulas (b1) to (b4).

Chemical formula

[0013] If it is such a thing, since the repeating units b1 to b4 have the function of 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. By uniformly dispersing the acid generator, LWR is improved. Also, by using a base polymer containing the above repeating unit, the blending of an additive acid generator can be omitted.

[0014] In this case, it is preferable that one or more iodine atoms are contained in the above Z 2B .

[0015] When the anion part of the acid generator bonded to the polymer main chain contains an iodine atom, the number of photons absorbed increases, thereby improving the contrast in acid generation and further improving the edge roughness. By using a base polymer having the repeating units b1 and / or b2 containing one or more iodine atoms in the above Z 2B in the polymer main chain, the above effects are exhibited, the sensitivity is further improved, and LWR and CDU are further improved.

[0016] In the present invention, further, it is preferable that it contains a repeating unit c in which a hydrogen atom of either or both of a carboxy group and a phenolic hydroxy group is substituted with an acid labile group.

[0017] If it is such a positive resist material, it becomes a resist material with higher sensitivity and smaller dimensional variations.

[0018] In this case, it is preferable that the repeating unit c is at least one selected from a repeating unit c1 represented by the following formula (c1) and a repeating unit c2 represented by the following formula (c2). [Chemical formula] (In the formula, 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 having an ester bond, an ether bond or a lactone ring. Y 2 is a single bond, an ester bond or an amide bond. R 11 and R 12 are acid-labile groups. 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 a linear or branched alkanediyl group having 1 to 6 carbon atoms, and a part of its carbon atoms may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer from 0 to 4.)

[0019] For such a positive resist material, the dissolution contrast can be further increased, and the dimensional variation can be made smaller.

[0020] Further, in the present invention, it is preferable that the base polymer further contains a repeating unit d 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-.

[0021] For such a resist material, a positive resist material excellent in adhesion to a substrate is obtained.

[0022] In the present invention, it is also preferable that the weight average molecular weight of the base polymer is in the range of 1,000 to 100,000.

[0023] With such a positive resist material, it will have excellent heat resistance, maintain alkali solubility, and become a resist material that does not cause a trailing phenomenon after pattern formation.

[0024] The present invention also provides a positive resist composition, which is characterized by containing the above positive resist material.

[0025] With such a composition, it will be a positive resist composition with higher sensitivity than conventional ones, small dimensional variations, and a good pattern shape after exposure.

[0026] In the present invention, it is further preferable that the composition contains one or more selected from an acid generator, an organic solvent, a quencher, and a surfactant.

[0027] Such substances can be added to the positive resist composition of the present invention.

[0028] The present invention also provides a pattern formation method, which includes a step of forming a resist film on a substrate using the above positive resist composition, a step of exposing the resist film with high-energy rays, and a step of developing the exposed resist film using a developer.

[0029] With such a pattern formation method, a pattern with a good pattern shape can be formed.

[0030] In this case, as the high-energy rays, it is preferable to use i-line, KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet light with a wavelength of 3 to 15 nm.

[0031] Such high-energy rays can be used in the pattern formation method of the present invention.

[0032] The present invention also provides a polymer compound having a weight average molecular weight in the range of 1,000 to 100,000, which is a copolymer having either or both of the repeating units represented by the following general formula (a)-1 and the repeating unit represented by (a)-2, and one or more repeating units selected from the following general formulas (b1) to (b4).

Chemical formula

Chemical formula

[0033] Such a polymer compound is useful as a base polymer that provides a positive resist material having higher sensitivity than conventional positive resist materials, small dimensional variations, and a good pattern shape after exposure.

Advantages of the Invention

[0034] As described above, the positive resist material, the positive resist composition, and the pattern forming method using the composition of the present invention can provide a resist material having higher sensitivity and higher resolution than conventional positive resist materials, small edge roughness and dimensional variations, and a good pattern shape after exposure, a resist composition using the resist material, and a pattern forming method.

Embodiments for Carrying Out the Invention

[0035] As described above, there has been a demand for the development of a resist material that has higher sensitivity and higher resolution than conventional positive resist materials, has small edge roughness and dimensional variations, and has a good pattern shape after exposure, a resist composition using the resist material, and a patterning method.

[0036] As a result of intensive studies to obtain a positive resist material with high resolution, small edge roughness (LWR) and dimensional variation (CDU), which have been demanded in recent years, the present inventors have found that it is necessary to shorten the acid diffusion distance to the limit and to make the acid concentration in the resist film in the exposed area uniform. To this end, it has been found that a polymer having a sulfonium salt or iodonium salt of a carboxylic acid containing an iodine atom as a repeating unit as a base polymer is effective, and the present invention has been completed.

[0037] That is, the present invention is a positive resist material comprising a base polymer in which a sulfonium salt or iodonium salt of a carboxylic acid is bonded as a pendant group to a polymer main chain, wherein the base polymer contains a repeating unit a containing one or more iodine atoms between the polymer main chain and the carboxylate, and the repeating unit a contains either or both of a repeating unit represented by the following general formula (a)-1 and a repeating unit represented by (a)-2. A positive resist material characterized by the above. [Chemical formula] (In the formula, R A is a hydrogen atom or a methyl group. X 1 is a single bond, an ester group, an ether group, or a sulfonic acid ester group. X 2 is a single bond, or a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms, and may contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. X 3is a linear or branched alkylene group having 1 to 10 carbon atoms and 1 to 4 fluorine atoms, and may have one or more selected from an ether group, an ester group, an aromatic group, a double bond, and a triple bond. R 1 each independently represents a hydroxy group, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. R 1A each independently represents a halogen atom, a hydroxy group, a linear or branched alkoxy group having 1 to 6 carbon atoms, or an acyloxy group. l is an integer from 0 to 3. m is an integer from 0 to 4, and n is an integer from 0 to 4. However, the anionic part of the pendant group contains one or more iodine atoms. R 2 ~R 6 each independently represents a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a heteroatom. Also, R 2 、R 3 and R 4 any two of them may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. )

[0038] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0039] [Positive resist material] The positive resist material of the present invention is a positive resist material comprising a base polymer having a sulfonium salt or iodonium salt of a carboxylic acid bonded as a pendant group to a polymer main chain, wherein the base polymer contains a repeating unit a containing one or more iodine atoms between the polymer main chain and the carboxylate, and the repeating unit a contains either or both of a repeating unit represented by the following general formula (a)-1 (also referred to as repeating unit a1. The same applies hereinafter) and a repeating unit represented by (a)-2 (repeating unit a2). The above base polymer is characterized in that the pendant group bonded to its main chain has a sulfonium salt or iodonium salt structure of a carboxylic acid containing one or more iodine atoms in its anionic part. The base polymer can further have a sulfonium salt or iodonium salt of sulfonic acid as a repeating unit. Furthermore, in order to further improve the dissolution contrast, by introducing a repeating unit in which a hydrogen atom of a carboxy group or phenolic hydroxy group is substituted with an acid-labile group, the sensitivity is high, the alkali dissolution rate contrast before and after exposure is significantly high, the effect of suppressing acid diffusion at high sensitivity is high, it has high resolution, the pattern shape, edge roughness, and dimensional variation after exposure are small and good, and a resist material particularly suitable as a fine pattern forming material for ultra-LSI manufacturing or photomasks can be obtained. [Chemical formula] (In the formula, R A is a hydrogen atom or a methyl group. X 1 is a single bond, an ester group, an ether group, or a sulfonic acid ester group. X 2 is a single bond, or a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms, and may contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. X 3 is a linear or branched alkylene group having 1 to 10 carbon atoms and having 1 to 4 fluorine atoms, and may have one or more selected from an ether group, an ester group, an aromatic group, a double bond, and a triple bond. R 1 are each independently a hydroxy group, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. R 1A are each independently a halogen atom, a hydroxy group, or a linear or branched alkoxy group having 1 to 6 carbon atoms, or an acyloxy group. l is an integer of 0 to 3. m is an integer of 0 to 4, and n is an integer of 0 to 4. However, the anion part of the pendant group contains one or more iodine atoms. R 2 ~R 6 are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a hetero atom. Also, R 2 、R 3 and R4 Any two of them may combine with each other to form a ring together with the sulfur atom to which they are attached.)

[0040] In the formula, R A is a hydrogen atom or a methyl group, and a hydrogen atom is preferred. X 1 is a single bond, an ester group, an ether group, or a sulfonic acid ester group, and an ether group is preferred. X 2 is a single bond or a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms, and may contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom, and those containing an ether group are preferred. X 3 is a linear or branched alkylene group having 1 to 10 carbon atoms, and may have one or more selected from an ether group, an ester group, an aromatic group, a double bond, and a triple bond, and has 1 to 4 fluorine atoms, and those having 2 fluorine atoms are preferred. R 1 are each independently a hydroxy group, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine, and a fluorine atom is preferred. R 1A are each independently a halogen atom, a hydroxy group, or a linear or branched alkoxy group having 1 to 6 carbon atoms, or an acyloxy group, and a halogen atom (selected from fluorine, chlorine, bromine, and iodine) or a hydroxy group is preferred. l is an integer from 0 to 3, m is an integer from 0 to 4, n is an integer from 0 to 4, and l = 0 to 1, m = 1 to 2, n = 0 to 1 are preferred. However, the anionic part of the pendant group contains one or more iodine atoms. R 2 ~R 6 are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms, preferably 1 to 20 carbon atoms, which may contain a heteroatom, and an aromatic hydrocarbon group is preferred. The aromatic group can be a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group.)

[0041] The repeating unit a is a quencher containing at least one iodine atom between the polymer main chain and the carboxylate at the end of the pendant group, and the base polymer is a quencher-bound polymer. The repeating unit a preferably has a sulfonium salt or iodonium salt structure of a carboxylic acid having an iodinated benzene ring skeleton and a fluorine atom. The quencher-bound polymer has a high effect of suppressing acid diffusion and is excellent in resolution as described above. Thereby, high resolution, low LWR, and low CDU can be achieved. Further, by having a skeleton in which the polymer main chain and the benzene ring are directly bonded, the etching resistance can be improved.

[0042] Examples of the anionic part of the monomers that give the repeating units a1 and a2 include, but are not limited to, those shown below. In the following formulas, R A is the same as described above.

[0043]

Chemical formula

[0044]

Chemical formula

[0045]

Chemical formula

[0046]

Chemical formula

[0047]

Chemical formula

[0048]

Chemical formula

[0049]

Chem.

[0050]

Chem.

[0051] Examples of the cation of the sulfonium salt represented by the general formula (a)-1 include, but are not limited to, those shown below. Regarding the substituents on the benzene ring, all possible positions for the o-, m-, and p-positions are included, and representative examples are given below. The same applies hereinafter.

Chem.

[0052]

Chem.

[0053]

Chem.

[0054]

Chem.

[0055]

Chem.

[0056]

Chem.

[0057]

Chem.

[0058]

Chem.

[0059]

Chem.

[0060]

Chem.

[0061]

Chem.

[0062]

Chem.

[0063]

Chem.

[0064]

Chem.

[0065]

Chem.

[0066]

Chem.

[0067]

Chem.

[0068]

Chem.

[0069] Examples of the cation of the iodonium salt represented by the general formula (a)-2 include, but are not limited to, those shown below.

[0070] [Chemical formula]

[0071] The base polymer may contain a repeating unit in which a hydrogen atom of a carboxy group is substituted with an acid-labile group (hereinafter also referred to as repeating unit c1), and / or a repeating unit in which a hydrogen atom of a phenolic hydroxy group is substituted with an acid-labile group (hereinafter also referred to as repeating unit c2) in order to enhance the dissolution contrast.

[0072] [Chemical formula] (In the formula, R A is each 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 having an ester bond, an ether bond or a lactone ring. Y 2 is a single bond, an ester bond or an amide bond. R 11 and R 12 are acid-labile groups. 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 a linear or branched alkanediyl group having 1 to 6 carbon atoms, and a part of the carbon atoms thereof may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4.)

[0073] Examples of the monomer that gives the repeating unit c1 include, but are not limited to, those shown below. In the following formulas, R A and R 11 are the same as those described above. [Chemistry]

[0074] [Chemistry]

[0075] Examples of the monomer that gives the repeating unit c2 include, but are not limited to, those shown below. In the following formula, R A and R 12 are the same as described above. [Chemistry]

[0076] R 11 or R 12 The acid-labile groups represented by are variously selected. For example, those represented by the following formulas (AL-1) to (AL-3) can be mentioned. [Chemistry]

[0077] 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 carbonyl group, an ether bond or an ester bond-containing saturated hydrocarbyl group having 4 to 20 carbon atoms, or a group represented by formula (AL-3).

[0078] R L1The tertiary hydrocarbyl group represented by [[ID=]] is 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 trialkylsilyl group include a trimethylsilyl group, a triethylsilyl group, and a dimethyl-tert-butylsilyl group. The saturated hydrocarbyl group containing a carbonyl group, an ether bond or an ester bond may be linear, branched or cyclic, but a cyclic one is preferred. Specific examples thereof include a 3-oxocyclohexyl group, a 4-methyl-2-oxooxan-4-yl group, a 5-methyl-2-oxooxolane-5-yl group, a 2-tetrahydropyranyl group, a 2-tetrahydrofuranyl group, and the like.

[0079] 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.

[0080] 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] (In the formula, the broken line represents a bond.)

[0081] 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.

[0082] In formula (AL-2), R L2 and R L3 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 18, 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, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a cyclopentyl group, a cyclohexyl group, a 2-ethylhexyl group, an n-octyl group, and the like.

[0083] In formula (AL-2), R L4 is a hydrocarbyl group having 1 to 18, 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 a part 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 substituted saturated hydrocarbyl groups include those shown below.

Chemical formula

[0084] R L2 and R L3 and, R L2 and R L4 and, or R L3and R L4 and may form a ring together with the carbon atom to which they are attached, or 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.

[0085] 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. [Chemical formula]

[0086] [Chemical formula]

[0087] [Chemical formula]

[0088] [Chemical formula]

[0089] Among the acid-labile groups represented by formula (AL-2), cyclic ones include a tetrahydrofuran-2-yl group, a 2-methyltetrahydrofuran-2-yl group, a tetrahydropyran-2-yl group, a 2-methyltetrahydropyran-2-yl group, and the like.

[0090] 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. [Chemical formula] (In the formula, the broken line represents a bond.)

[0091] 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 L12 may be bonded to each other to form a ring together with the carbon atom to which they are bonded. In this case, R L11 and R L12 are each independently an alkanediyl group having 1 to 8 carbon atoms. R L13 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 from 0 to 10, preferably an integer from 0 to 5, and f is an integer from 1 to 7, preferably an integer from 1 to 3.

[0092] 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. Also, a part of the carbon atoms of these groups may be substituted with a heteroatom-containing group, and a part of the hydrogen atoms bonded to the carbon 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, or a tetravalent saturated hydrocarbon group, or an arylene group having 6 to 30 carbon atoms is preferable. The saturated hydrocarbon group may be linear, branched, or cyclic. LB is -C(=O)-O-, -NH-C(=O)-O- or -NH-C(=O)-NH-.

[0093] 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

[0094] In formula (AL-3), R L5 , R L6 and R L7 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, and 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 , R L5 and R L7 , or R L6 and R L7 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.

[0095] Examples of the group represented by formula (AL-3) include a tert-butyl group, a 1,1-diethylpropyl group, a 1-ethylnorbornyl group, a 1-methylcyclopentyl group, a 1-isopropylcyclopentyl group, a 1-ethylcyclopentyl group, a 1-methylcyclohexyl group, a 2-(2-methyl)adamantyl group, a 2-(2-ethyl)adamantyl group, a tert-pentyl group, and the like.

[0096] 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] (In the formula, the dashed line represents a bond.)

[0097] In Formulas (AL-3)-1 to (AL-3)-19, R L14 is each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms, or an aryl group having 6 to 20 carbon atoms. R L15 and R L17 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 20 carbon atoms. R L16 is 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.

[0098] 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] (In the formula, the dashed line represents a bond.)

[0099] In Formulas (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.

[0100] Examples of the monomer that provides a repeating unit containing the acid-labile group represented by Formula (AL-3) include a (meth)acrylate ester containing an exo structure represented by the following Formula (AL-3)-22. [Chemical formula]

[0101] In formula (AL-3)-22, R A is the same as described above. R Lc1 is a saturated hydrocarbyl group having 1 to 8 carbon atoms or an aryl group having 6 to 20 carbon atoms which may be substituted. The saturated hydrocarbyl group may be linear, branched or cyclic. R Lc2 ~R Lc11 are each independently a hydrocarbyl group having 1 to 15 carbon atoms which may contain a heteroatom. Examples of the heteroatom include an oxygen atom. Examples of the hydrocarbyl group include an alkyl group having 1 to 15 carbon atoms, an aryl group having 6 to 15 carbon atoms, etc. R Lc2 and R Lc3 and, R Lc4 and R Lc6 and, R Lc4 and R Lc7 and, R Lc5 and R Lc7 and, R Lc5 and R Lc11 and, R Lc6 and R Lc10 and, R Lc8 and R Lc9 and, or R Lc9 and R Lc10 and may be bonded to each other to form a ring together with the carbon atom to which they are bonded. In this case, the group involved in the bond is a hydrocarbylene group which may contain a heteroatom having 1 to 15 carbon atoms. Also, R Lc2 and R Lc11 and, R Lc8 and R Lc11 and, or R Lc4 and R Lc6 and may be bonded to each other without any intervening group between those bonded to adjacent carbons to form a double bond. Note that this formula also represents enantiomers.

[0102] Here, examples of the monomer that gives the repeating unit represented by formula (AL-3)-22 include those described in JP-A-2000-327633. Specifically, the following are examples, but not limited thereto. In the following formulas, R A is the same as described above. [Chemical formula]

[0103] Examples of the monomer that gives the repeating unit containing the acid-labile group represented by formula (AL-3) also include (meth)acrylic acid esters containing a furandiyl group, a tetrahydrofurandiyl group, or an oxanorbornyl group, represented by the following formula (AL-3)-23. [Chemical formula]

[0104] In formula (AL-3)-23, R A is the same as described above. R Lc12 and R Lc13 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. R Lc12 and R Lc13 may be bonded to each other to form an alicyclic ring together with the carbon atom to which they are bonded. R Lc14 is a furandiyl group, a tetrahydrofurandiyl group, or an oxanorbornyl group. R Lc15 is a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms which may contain a hetero atom. The hydrocarbyl group may be linear, branched, or cyclic. Specific examples thereof include saturated hydrocarbyl groups having 1 to 10 carbon atoms.

[0105] Examples of the monomer that gives the repeating unit represented by formula (AL-3)-23 include the following, but are not limited thereto. In the following formulas, R A is the same as described above, Ac is an acetyl group, and Me is a methyl group. [Chemical formula]

[0106]

Chem.

[0107] The base polymer may further contain a repeating unit d 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-.

[0108] Examples of the monomer that gives the repeating unit d include, but are not limited to, those shown below. In the following formulas, R A is the same as described above.

Chem.

[0109]

Chem.

[0110]

Chem.

[0111]

Chem.

[0112]

Chem.

[0113]

Chem.

[0114]

Chem.

[0115]

Chem.

[0116] The base polymer may further contain a repeating unit b derived from an onium salt containing a polymerizable unsaturated bond. Preferred repeating units b include a repeating unit represented by the following formula (b1) (hereinafter, also referred to as repeating unit b1), a repeating unit represented by the following formula (b2) (hereinafter, also referred to as repeating unit b2), a repeating unit represented by the following formula (b3) (hereinafter, also referred to as repeating unit b3), and a repeating unit represented by the following formula (b4) (hereinafter, also referred to as repeating unit b4). Note that the repeating units b1 to b4 can be used alone or in combination of two or more.

Chem.

[0117] In formulas (b1) to (b4), R A is independently a hydrogen atom or a methyl group. Z 2A is a single bond or an ester bond. Z 2B is a single bond or a divalent group having 1 to 12 carbon atoms, and may contain an ester bond, an ether bond, a lactone ring, a bromine atom or an iodine atom. Z 3 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, -O-Z 31 -, -C(=O)-O-Z 31 - or -C(=O)-NH-Z 31 -, and Z 31 is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms or a phenylene group, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom or a hydroxy group.

[0118] said Z 2B preferably contains one or more iodine atoms therein. As described later, when the anion moiety of the acid generator bonded to the polymer main chain contains an iodine atom, the number of photons absorbed increases, thereby improving the contrast in acid generation and further improving the edge roughness. said Z 2B By using a base polymer having a repeating unit b1 and / or b2 containing one or more iodine atoms in the polymer main chain, the above effects are exhibited, the sensitivity is further improved, and the LWR and CDU are further improved.

[0119] In formulas (b1) to (b2), 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. In particular, it is preferable that at least one of Rf 3 and Rf 4 is a fluorine atom, and it is more preferable that both Rf 3 and Rf 4 are fluorine atoms.

[0120] In formulas (b1) to (b4), R 23 ~R 27 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. Also, R 23 , R 24 and R 25Any two of them may be combined with each other to form a ring together with the sulfur atom to which they are attached. The monovalent hydrocarbon group may be linear, branched or cyclic, and specific examples thereof include an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and the like. Further, some or all of the hydrogen atoms of these groups may be substituted with an alkyl group having 1 to 10 carbon atoms, a halogen atom, a trifluoromethyl group, a cyano group, a nitro group, a hydroxy group, a mercapto group, an alkoxy group having 1 to 10 carbon atoms, an alkoxycarbonyl group having 2 to 10 carbon atoms, or an acyloxy group having 2 to 10 carbon atoms, and some of the carbon atoms of these groups may be substituted with a carbonyl group, an ether bond or an ester bond.

[0121] In formulas (b1) and (b3), specific examples of the sulfonium cation include the same ones as those exemplified as the cation of the sulfonium salt represented by the general formula (a)-1 described above.

[0122] In formulas (b2) and (b4), specific examples of the iodonium cation include the same ones as those exemplified as the cation of the iodonium salt represented by the general formula (a)-2 described above.

[0123] Examples of the monomer that gives the repeating unit b1 include, but are not limited to, the following. In the following formulas, R A is the same as described above.

Chemical formula

[0124]

Chemical formula

[0125]

Chemical formula

[0126]

Chemical formula

[0127]

Chem.

[0128] Examples of the monomer that provides the repeating unit b2 include those obtained by replacing the sulfonium cation of the monomers shown above with the iodonium cation exemplified above, but are not limited thereto.

[0129] In addition, monomers that provide the repeating units b1 and b2 preferably include those having the anions shown below. In the following formula, R A is the same as described above.

Chem.

[0130]

Chem.

[0131]

Chem.

[0132]

Chem.

[0133]

Chem.

[0134]

Chem.

[0135]

Chem.

[0136]

Chem.

[0137] Examples of the monomer that gives the repeating unit b3 include, but are not limited to, the following. In the following formula, R A is the same as described above.

Chem.

[0138]

Chem.

[0139] Examples of the monomer that gives the repeating unit b4 include those obtained by replacing the sulfonium cation of the above-exemplified monomers with the iodonium cation exemplified above, but are not limited thereto.

[0140] The repeating units b1 to b4 have the function of an acid generator. By bonding an 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 is improved by the uniform dispersion of the acid generator. When using the base polymer containing the repeating unit b described above, the blending of the additive acid generator described later can be omitted.

[0141] By copolymerizing the repeating units a1 and / or a2 having the function of a quencher of a sulfonium salt or iodonium salt of a substituted or unsubstituted iodinated benzoic acid bonded via an ester bond from the polymer main chain of the present invention and the repeating units having the function of an acid generator of b1 to b4, all functions can be contained in one polymer. In this case, the materials added other than the polymer may be only an organic solvent or a surfactant, and since the material composition is simple, there is an advantage of high productivity.

[0142] The polymerization rate of the monomer having a double bond that functions as a quencher used in the present invention is comparable to the polymerization rate of the monomer having a double bond that functions as an acid generator. Therefore, due to copolymerization, the quencher and the acid generator are uniformly present in the polymer. As a result, the edge roughness after development is improved. When iodine is contained in the anion moiety of the acid generator, the edge roughness is further improved due to an increase in the contrast in acid generation by an increase in the number of photons absorbed. The repeating unit having a sulfonium salt or iodonium salt of the iodinated carboxylic acid of the present invention improves the contrast of quencher decomposition due to an increase in the number of photons absorbed by the absorption of iodine, and thereby exhibits the effect of improving the edge roughness.

[0143] The base polymer may further contain a repeating unit e that does not contain an amino group and contains an iodine atom. 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

[0144]

Chemical formula

[0145] 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, and the like.

[0146] In the base polymer, when the content ratios of the repeating units a1, a2, b1, b2, b3, b4, c1, c2, d, e, and f are represented by the molar fractions of the repeating units as a1, a2, b1, b2, b3, b4, c1, c2, d, e, and f, respectively, 0 ≦ a1 < 1.0, 0 ≦ a2 < 1.0, 0 < a1 + a2 < 1.0, 0 ≦ b1 ≦ 0.5, 0 ≦ b2 ≦ 0.5, 0 ≦ b3 ≦ 0.5, 0 ≦ b4 ≦ 0.5, 0 ≦ b1 + b2 + b3 + b4 ≦ 0.9, 0 ≦ c1 ≦ 0.5, 0 ≦ c2 ≦ 0.5, 0 ≦ c1 + c2 ≦ 0.9, 0 ≦ d ≦ 0.5, 0 ≦ e ≦ 0.5, and 0 ≦ f ≦ 0.5 are preferred, 0.001 ≦ a1 ≦ 0.8, 0.001 ≦ a2 ≦ 0.8, 0.001 ≦ a1 + a2 ≦ 0.8, 0 ≦ b1 ≦ 0.8, 0 ≦ b2 ≦ 0.8, 0 ≦ b3 ≦ 0.8, 0 ≦ b4 ≦ 0.8, 0 ≦ b1 + b2 + b3 + b4 ≦ 0.8, 0 ≦ c1 ≦ 0.8, 0 ≦ c2 ≦ 0.8, 0 ≦ c1 + c2 ≦ 0.8, 0 ≦ d ≦ 0.4, 0 ≦ e ≦ 0.4, and 0 ≦ f ≦ 0.4 are more preferred, and 0.005 ≦ a1 ≦ 0.7, 0.005 ≦ a2 ≦ 0.7, 0.005 ≦ a1 + a2 ≦ 0.7, 0 ≦ b1 ≦ 0.7, 0 ≦ b2 ≦ 0.7, 0 ≦ b3 ≦ 0.7, 0 ≦ b4 ≦ 0.7, 0 ≦ b1 + b2 + b3 + b4 ≦ 0.7, 0 ≦ c1 ≦ 0.7, 0 ≦ c2 ≦ 0.7, 0 ≦ c1 + c2 ≦ 0.7, 0 ≦ d ≦ 0.3, 0 ≦ e ≦ 0.3, and 0 ≦ f ≦ 0.4 are even more preferred. However, a1 + a2 + b1 + b2 + b3 + b4 + c1 + c2 + d + e + f = 1.0.

[0147] To synthesize the base polymer, for example, monomers that provide the aforementioned repeating units may be heated in an organic solvent with a radical polymerization initiator added thereto to perform polymerization.

[0148] 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.

[0149] When copolymerizing a monomer containing a hydroxy group, the hydroxy group may be substituted with an acetal group that can be 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.

[0150] 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.

[0151] Examples of the base used during alkaline hydrolysis include aqueous ammonia, triethylamine, and the like. 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.

[0152] The base polymer preferably has a polystyrene-equivalent weight average molecular weight (Mw) of 1,000 to 100,000, more preferably 2,000 to 30,000, as determined by gel permeation chromatography (GPC) using THF as a solvent. If Mw is 1,000 or more, the resist material has excellent heat resistance, and if it is 100,000 or less, the alkali solubility is sufficient and no trailing phenomenon occurs after pattern formation.

[0153] 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 pattern shape will deteriorate after exposure. As the pattern rules are miniaturized, the influence of Mw and Mw / Mn tends to increase. Therefore, in order to obtain a resist material 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 1.7.

[0154] The base polymer may contain two or more polymers having different composition ratios, Mw, and Mw / Mn. Also, a polymer containing repeating unit a and a polymer not containing repeating unit a may be blended.

[0155] [Positive resist composition] The present invention also provides a positive resist composition characterized by containing the above positive resist material (base polymer). The positive resist composition can further contain one or more selected from an acid generator, an organic solvent, a quencher, and a surfactant. By blending such additives as necessary, the properties of the above composition and its cured product can be made preferable. These will be described below.

[0156] [Acid generator] The positive resist composition of the present invention may further 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. Examples of the acid generator include compounds that generate an acid upon exposure to actinic rays or radiation (photoacid generators). 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.

[0157] Also, as the photoacid generator, a sulfonium salt represented by the following formula (1-1) and an iodonium salt represented by the following formula (1-2) can also be preferably used.

Chemical formula

[0158] In formulas (1-1) and (1-2), R 101 ~R 105 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. Further, any two of R 101 , R 102 and R 103 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. The monovalent hydrocarbon group may be linear, branched, or cyclic, and specific examples thereof include the same ones as those described above.

[0159] In formulas (1-1) and (1-2), X - is an anion selected from the following formulas (1A) to (1D).

Chemical formula

[0160] In formula (1A), R fa is a fluorine atom or a hydrocarbyl group having 1 to 40 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 R in formula (1A’) 107 which is the same as those described later as the hydrocarbyl group represented by.

[0161] As the anion represented by formula (1A), those represented by the following formula (1A’) are preferable.

Chemical formula

[0162] In formula (1A’), R 106 is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R 107 is a hydrocarbyl group having 1 to 38 carbon atoms which may contain a hetero atom. As the hetero atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom and the like 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.

[0163] R 107The hydrocarbyl group represented by [[ ]] may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, 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, icosanyl group; cycloalkyl saturated hydrocarbyl groups 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 hydrocarbyl groups such as allyl group, 3-cyclohexenyl group; aryl groups such as phenyl group, 1-naphthyl group, 2-naphthyl group; aralkyl groups such as benzyl group, diphenylmethyl group, etc.

[0164] In addition, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atom, sulfur atom, nitrogen atom, halogen atom, etc., and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atom, sulfur atom, nitrogen atom, etc. 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 group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. Examples of the hydrocarbyl group containing a heteroatom include tetrahydrofuryl group, methoxymethyl group, ethoxymethyl group, methylthiomethyl group, acetamidomethyl group, trifluoroethyl group, (2-methoxyethoxy)methyl group, acetoxymethyl group, 2-carboxy-1-cyclohexyl group, 2-oxopropyl group, 4-oxo-1-adamantyl group, 3-oxocyclohexyl group, etc.

[0165] Regarding the synthesis of sulfonium salts containing anions represented by formula (1A’), details can be found in JP-A-2007-145797, JP-A-2008-106045, JP-A-2009-7327, JP-A-2009-258695, etc. Further, 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.

[0166] Examples of the anion represented by formula (1A) include those similar to those exemplified as the anion represented by formula (1A) in JP-A-2018-197853.

[0167] In 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 hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include those similar to those exemplified in the description of R 107 in formula (1A’). Preferably, R fb1 and R fb2 are a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. Further, R fb1 and R fb2 may be bonded to each other to form a ring together with the group (-CF2-SO2-N - -SO2-CF2-) 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.

[0168] 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 hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include those similar to those exemplified in the description of R in formula (1A’)107 Those similar to those exemplified in the description of R fc1 are mentioned. R fc2 and R fc3 are preferably 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 (-CF2-SO2-C - -SO2-CF2-) 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.

[0169] 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 those similar to those exemplified in the description of R 107 in formula (1A’).

[0170] 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.

[0171] Examples of the anion represented by formula (1D) include those similar to those exemplified as the anion represented by formula (1D) in JP-A-2018-197853.

[0172] Note that the photoacid generator containing the anion represented by formula (1D) does not have fluorine 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.

[0173] Furthermore, as the photoacid generator, those represented by the following formula (2) can also be preferably used. [Chemical formula]

[0174] In formula (2), R 201 and R 202 are each independently a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. R 203 is a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. Further, R 201 and R 202 or R 201 and R 203 may combine with each other to form a ring together with the sulfur atom to which they are attached. At this time, as the ring, in the description of formula (1-1), those similar to the rings that can be formed by the combination of R 101 and R 102 together with the sulfur atom to which they are attached are exemplified.

[0175] R 201 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 such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl 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 2,6Cyclic saturated hydrocarbyl groups such as decanyl group and adamantyl group; 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, anthracenyl group and the like can be mentioned. Further, part or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atom, sulfur atom, nitrogen atom, halogen atom, etc., and part of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atom, sulfur atom, nitrogen atom, etc. 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 group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group and the like.

[0176] R 203The hydrocarbylene group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkane diyl groups such as methylene group, ethylene 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 such as cyclopentane diyl group, cyclohexane diyl group, norbornane diyl group, adamantane diyl 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. Further, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atom, sulfur atom, nitrogen atom, halogen atom, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atom, sulfur atom, nitrogen atom, and 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 group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. As the heteroatom, an oxygen atom is preferable.

[0177] In formula (2), L 1 is a single bond, an ether bond, or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R203 Those similar to those exemplified as the hydrocarbylene group represented by are mentioned.

[0178] 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.

[0179] In formula (2), k is an integer from 0 to 3.

[0180] As the photoacid generator represented by formula (2), those represented by the following formula (2’) are preferable.

Chemical formula

[0181] In formula (2’), L 1 is the same as above. R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R 301 , R 302 and R 303 are each independently 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 those exemplified in the description of R 107 in formula (1A’). x and y are each independently an integer from 0 to 5, and z is an integer from 0 to 4.

[0182] As the photoacid generator represented by formula (2), those similar to those exemplified as the photoacid generator represented by formula (2) in JP-A-2017-026980 are mentioned.

[0183] Among the photoacid generators, those containing an anion represented by the formula (1A') or (1D) are particularly preferred because they have low acid diffusion and excellent solubility in the resist solvent. Also, those represented by the formula (2') are particularly preferred because they have extremely low acid diffusion.

[0184] Furthermore, as the photoacid generator, a sulfonium salt or an iodonium salt having an anion containing an aromatic ring substituted with an iodine atom or a bromine atom can also be used. Examples of such salts include those represented by the following formula (3-1) or (3-2).

Chemical formula

[0185] In the 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.

[0186] In the formulas (3-1) and (3-2), X BI is an iodine atom or a bromine atom, and when q is 2 or more, they may be the same or different from each other.

[0187] In the 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.

[0188] In the formulas (3-1) and (3-2), L 12 is a single bond or a divalent linking group having 1 to 20 carbon atoms when r is 1, and a trivalent or tetravalent linking group having 1 to 20 carbon atoms when r is 2 or 3, and the linking group may contain an oxygen atom, a sulfur atom or a nitrogen atom.

[0189] In the formulas (3-1) and (3-2), R401 is a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbyloxycarbonyl group having 2 to 10 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms or a saturated hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms, which may contain a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom or an amino group, or a fluorine atom, a chlorine atom, a bromine atom, a hydroxy group, an amino group or an ether bond, or -NR 401A -C(=O)-R 401B or -NR 401A -C(=O)-O-R 401B wherein R 401A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, which may contain a halogen atom, a hydroxy group, an alkoxy 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 401B is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms or an aryl group having 6 to 12 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. The aliphatic hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbyloxycarbonyl group, saturated hydrocarbylcarbonyl group and saturated hydrocarbylcarbonyloxy group may be linear, branched or cyclic. When p and / or r is 2 or more, each R 401 may be the same as or different from each other.

[0190] Among these, as R 401 , a hydroxy group, -NR 401A -C(=O)-R 401B , -NR 401A -C(=O)-O-R 401B , a fluorine atom, a chlorine atom, a bromine atom, a methyl group, a methoxy group and the like are preferable.

[0191] In formulas (3-1) and (3-2), Rf 11 ~Rf 14 is independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, provided that at least one of these is a fluorine atom or a trifluoromethyl group. Also, 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.

[0192] In formulas (3-1) and (3-2), R 402 , R 403 , R 404 , R 405 and R 406 are each independently a fluorine atom, a chlorine atom, a bromine atom, an iodine 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 101 ~R 105 in the description of formulas (1-1) and (1-2). Also, some or all of the hydrogen atoms of these groups may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sultone group, a sulfone group or a sulfonium salt-containing group, and some of the carbon atoms of these groups may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate group or a sulfonic acid ester bond. Also, R 402 and R 403 may combine with each other to form a ring together with the sulfur atom to which they are attached. At this time, examples of the ring include the same ones as those exemplified as the rings that can be formed together with the sulfur atom to which R 101 and R 102 are attached in the description of formula (1-1).

[0193] Examples of the cation of the sulfonium salt represented by formula (3-1) include the same ones as those exemplified as the cation of the sulfonium salt represented by formula (1-1). Examples of the cation of the iodonium salt represented by formula (3-2) include the same ones as those exemplified as the cation of the iodonium salt represented by formula (1-2).

[0194] Examples of the anion of the onium salt represented by formula (3-1) or (3-2) include, but are not limited to, the following. In the following formulas, X BI is the same as described above.

Chemical formula

[0195]

Chemical formula

[0196]

Chemical formula

[0197]

Chemical formula

[0198]

Chemical formula

[0199]

Chemical formula

[0200]

Chemical formula

[0201]

Chemical formula

[0202]

Chem.

[0203]

Chem.

[0204]

Chem.

[0205]

Chem.

[0206]

Chem.

[0207]

Chem.

[0208]

Chem.

[0209]

Chem.

[0210]

Chem.

[0211]

Chem.

[0212] [Chemistry]

[0213] [Chemistry]

[0214] [Chemistry]

[0215] [Chemistry]

[0216] [Chemistry]

[0217] In the resist composition of the present invention, the content of the additive acid generator is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, per 100 parts by mass of the base polymer. By including the repeating units b1 to b4 in the base polymer and / or by including the additive acid generator, the positive resist composition of the present invention can function as a chemically amplified positive resist composition.

[0218] [Quencher] A quencher (hereinafter referred to as other quencher) may be blended in the resist composition of the present invention. Examples of the quencher include conventional basic compounds. Examples of the conventional basic compounds include primary, secondary, and tertiary aliphatic amines, hybrid 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, 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, a sulfonic acid ester bond, or compounds having a carbamate group described in Japanese Patent No. 3790649 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.

[0219] In addition, examples of other quenchers include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids and carboxylic acids 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 or carboxylic acids in which the α-position is not fluorinated are released by salt exchange with onium salts in which the α-position is not fluorinated. Since sulfonic acids and carboxylic acids in which the α-position is not fluorinated do not cause a deprotection reaction, they function as quenchers. In addition, examples of other quenchers include onium salts of carboxylic acids in which the α-position is fluorinated, as described in Japanese Patent No. 5904180. Since α-fluorocarboxylic acids have a lower acidity than sulfonic acids, they have a high quenching ability and can form a pattern with good roughness and resolution.

[0220] Other quenchers include the polymer type quencher described in JP-A-2008-239918. This enhances the rectangularity of the resist after patterning by orienting on the resist surface after coating. 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.

[0221] In the resist composition of the present invention, the content of other quenchers is preferably 0 to 10 parts by mass, more preferably 0 to 7 parts by mass, per 100 parts by mass of the base polymer. The quenchers can be used singly or in combination of two or more.

[0222] [Organic Solvent] An organic solvent may be blended in the resist composition of the present invention. The organic solvent is not particularly limited as long as it can dissolve the above-described components and the components described below. Examples of such organic solvents include 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 mixed solvents thereof.

[0223] In the resist composition of the present invention, the content of the organic solvent is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass, based on 100 parts by mass of the base polymer.

[0224] [Other components] In addition to the components described above, a positive resist composition is constituted by appropriately combining and blending a surfactant, a dissolution inhibitor, etc. according to the purpose. In the exposed portion, the dissolution rate of the base polymer with respect to the developer is accelerated by a catalytic reaction. Therefore, a very high-sensitivity positive resist composition can be obtained. In this case, the dissolution contrast and resolution of the resist film are high, there is an exposure margin, the process adaptability is excellent, the pattern shape after exposure is good, and particularly the acid diffusion can be suppressed, so the difference in the fine and dense dimensions is small. From these facts, the practicality is high, and it can be made very effective as a resist material for ultra-LSI.

[0225] 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. The surfactant can be used alone or in combination of two or more. In the resist composition of the present invention, the content of the surfactant is preferably 0.0001 to 10 parts by mass based on 100 parts by mass of the base polymer.

[0226] By blending a dissolution inhibitor, the difference in the dissolution rate between the exposed portion and the unexposed portion can be further increased, and the resolution can be further improved.

[0227] As the dissolution inhibitor, a compound having a molecular weight preferably of 100 to 1,000, more preferably 150 to 800, and containing two or more phenolic hydroxy groups in the molecule, and having the hydrogen atoms of the phenolic hydroxy groups substituted by acid-labile groups in a proportion of 0 to 100 mol% as a whole, or a compound having a carboxy group in the molecule and having the hydrogen atoms of the carboxy group substituted by acid-labile groups in a proportion of 50 to 100 mol% on average as a whole can be mentioned. Specifically, compounds such as bisphenol A, trisphenol, phenolphthalein, cresol novolak, naphthalene carboxylic acid, adamantane carboxylic acid, and compounds in which the hydrogen atoms of the hydroxy groups and carboxy groups of cholic acid are substituted by acid-labile groups can be mentioned. For example, they are described in paragraphs

[0155] to

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

[0228] The content of the dissolution inhibitor is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass, per 100 parts by mass of the base polymer. The dissolution inhibitor can be used alone or in combination of two or more.

[0229] The resist composition of the present invention may contain a water repellency improver for improving the water repellency of the resist surface after spin coating. The water repellency improver can be used in immersion lithography without using a top coat. As the water repellency improver, a polymer compound containing an alkyl fluoride group, a polymer compound 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 more preferable. The water repellency improver needs to be soluble in 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 compound containing a repeating unit containing an amino group or an amine salt has a high effect of preventing the evaporation of acid during post-exposure bake (PEB) and preventing the opening failure of the hole pattern after development. The water repellency improver can be used alone or in combination of two or more. In the resist composition of the present invention, the content of the water repellency improver is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, based on 100 parts by mass of the base polymer.

[0230] The resist composition of the present invention may also contain acetylenic alcohols. Examples of the acetylenic alcohols include those described in paragraphs

[0179] to

[0182] of JP-A-2008-122932. In the resist composition of the present invention, the content of the acetylenic alcohols is preferably 0 to 5 parts by mass based on 100 parts by mass of the base polymer.

[0231] [Pattern Formation Method] When the resist composition of the present invention is used for manufacturing various integrated circuits, known lithography techniques can be applied.

[0232] For example, the positive resist composition of the present invention is spin-coated, roll-coated, flow-coated, dip-coated, spray-coated, doctor-coated, or the like on a substrate for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflection film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) by an appropriate coating method 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.

[0233] Next, the resist film is exposed using high-energy rays. Examples of the high-energy rays include ultraviolet rays such as i-line, far ultraviolet rays, electron beams (EB), extreme ultraviolet rays (EUV) with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer lasers such as KrF and ArF, γ-rays, synchrotron radiation, and the like. When using ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer lasers, γ-rays, synchrotron radiation, etc. as the high-energy rays, a mask for forming a target pattern is used, and the exposure dose is preferably 1 to 200 mJ / cm 2 or so, more preferably 10 to 100 mJ / cm 2 or so. When using EB as the high-energy rays, the exposure dose is preferably 0.1 to 100 μC / cm 2 or so, more preferably 0.5 to 50 μC / cm 2 or so, and it is drawn directly or using a mask for forming a target pattern. The resist composition of the present invention is particularly suitable for fine patterning by i-line, KrF excimer laser, ArF excimer laser, EB, or extreme ultraviolet EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, γ-rays, synchrotron radiation among high-energy rays, and is particularly suitable for fine patterning by EB or EUV. In the pattern forming method of the present invention, i-line, KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet ray with a wavelength of 3 to 15 nm can be used as the high-energy rays.

[0234] After exposure, PEB may be performed on a hot plate, preferably at 50 to 150 °C for 10 seconds to 30 minutes, more preferably at 60 to 120 °C for 30 seconds to 20 minutes.

[0235] 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 (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutylammonium hydroxide (TBAH), etc. is used, and development is carried out for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by a conventional method such as dip method, puddle method, spray method, etc. Thus, the irradiated part is dissolved in the developer, and the unexposed part is not dissolved, and a desired positive pattern is formed on the substrate.

[0236] Negative development can also be carried out to obtain a negative pattern by organic solvent development using a positive resist composition containing a base polymer containing an acid-labile group. As the developer used at this time, 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. can be mentioned. These organic solvents can be used alone or in combination of two or more.

[0237] 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.

[0238] Specifically, 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.

[0239] 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.

[0240] Examples of alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. Examples of alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Examples of alkynes having 6 to 12 carbon atoms include hexyne, heptyne, octyne, etc.

[0241] Examples of aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, mesitylene, etc.

[0242] Performing rinsing can reduce the collapse of the resist pattern and the occurrence of defects. Also, rinsing is not necessarily essential, and the amount of solvent used can be reduced by not performing rinsing.

[0243] The developed hole pattern or trench pattern can also be shrunk by thermal flow, RELACS technology, or DSA technology. A shrink agent is applied onto the hole pattern, and cross-linking of the shrink agent occurs on the surface of the resist due to the diffusion of the acid catalyst from the resist layer during baking, and the shrink agent adheres to the sidewalls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the time is preferably 10 to 300 seconds, to remove the excess shrink agent and shrink the hole pattern.

Examples

[0244] Hereinafter, synthesis examples, examples, and comparative examples will be shown to specifically describe the present invention, but the present invention is not limited to the following examples.

[0245] [1] Synthesis of Monomer [Synthesis Example 1] The following monomers 1 to 8 and comparative monomer 1 were obtained by ion-exchanging a sulfonium salt chloride with an iodine-containing carboxylic acid compound or a carboxylic acid compound having a polymerizable double bond.

[0246] [Chemical formula]

[0247] [2] Synthesis of polymer The acid-labile group monomers (ALG monomers 1 to 4) and PAG monomers 1 to 6 used for the synthesis of the polymer are as follows. The Mw of the polymer is the polystyrene-equivalent measurement value by GPC using THF as a solvent. [Chemical formula]

[0248] [Chemical formula]

[0249] [Synthesis Example 2-1] Synthesis of Polymer 1 To a 2 L flask, 3.0 g of monomer 1, 6.7 g of ALG monomer 4, 3.3 g of 3-hydroxystyrene, 7.1 g of PAG monomer 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 3 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 1. The composition of Polymer 1 was 13 confirmed by C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical formula]

[0250] [Synthesis Example 2-2] Synthesis of Polymer 2 To a 2 L flask, 3.4 g of Monomer 2, 9.1 g of ALG Monomer 1, 3.3 g of 3-hydroxystyrene, 8.2 g of PAG Monomer 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 2. The composition of Polymer 2 was 13 confirmed by C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC.

Chemical formula

[0251] [Synthesis Example 2-3] Synthesis of Polymer 3 To a 2 L flask, 3.4 g of Monomer 3, 6.7 g of ALG Monomer 3, 3.7 g of 3-methyl-4-hydroxystyrene, 8.3 g of PAG Monomer 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 3. The composition of Polymer 3 was 13 confirmed by C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC.

Chemical formula

[0252] [Synthesis Example 2-4] Synthesis of Polymer 4 To a 2 L flask, 5.8 g of monomer 4, 6.1 g of ALG monomer 2, 3.3 g of 3-hydroxystyrene, 5.7 g of PAG monomer 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 4. The composition of polymer 4 was 13 determined by 1 13C-NMR and [Chemical formula]

[0253] [Synthesis Example 2-5] Synthesis of Polymer 5 To a 2 L flask, 4.8 g of monomer 5, 6.6 g of ALG monomer 3, 3.3 g of 3-hydroxystyrene, 8.5 g of PAG monomer 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 5. The composition of polymer 5 was 13 determined by 1 13C-NMR and [Chemical formula]

[0254] [Synthesis Example 2-6] Synthesis of Polymer 6 Into a 2 L flask, 5.3 g of monomer 6, 6.6 g of ALG monomer 4, 3.3 g of 3-hydroxystyrene, 6.1 g of PAG monomer 1, 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 6. The composition of polymer 6 was 13 determined by C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical Formula]

[0255] [Synthesis Example 2-7] Synthesis of Polymer 7 Into a 2 L flask, 3.7 g of monomer 7, 6.2 g of ALG monomer 2, 3.3 g of 3-hydroxystyrene, 7.2 g of PAG monomer 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 7. The composition of polymer 7 was 13 determined by C-NMR and 1 H-NMR, and Mw and Mw / Mn were confirmed by GPC. [Chemical Formula]

[0256] [Synthesis Example 2-8] Synthesis of Polymer 8 To a 2 L flask, 3.5 g of monomer 8, 6.2 g of ALG monomer 2, 3.3 g of 3-hydroxystyrene, 7.2 g of PAG monomer 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 8. The composition of polymer 8 was 13 determined by 1 C-NMR and

Chemical formula

[0257] [Comparative Synthesis Example 1] Synthesis of Comparative Polymer 1 Comparative polymer 1 was obtained in the same manner as in Synthesis Example 2-2, except that monomer 2 was not used. The composition of comparative polymer 1 was 13 determined by 1 C-NMR and

Chemical formula

[0258] [Comparative Synthesis Example 2] Synthesis of Comparative Polymer 2 Comparative polymer 2 was obtained in the same manner as in Synthesis Example 2-4, except that comparative monomer 1 was used instead of monomer 4. The composition of comparative polymer 2 was 13 determined by 1 C-NMR and

Chemical formula

[0259] [Comparative Synthesis Example 3] Synthesis of Comparative Polymer 3 A comparative polymer 3 was obtained in the same manner as in Synthesis Example 2-4, except that monomer 4 and PAG monomer 2 were not used. The composition of comparative polymer 3 is 13 C-NMR and 1 H-NMR were used to confirm Mw and Mw / Mn by GPC. [Chemical formula]

[0260] [Examples 1 to 17, Comparative Examples 1 to 3] A solution in which each component was dissolved in the composition shown in Tables 1 and 2 was prepared in a solvent in which 50 ppm of the surfactant Polyfox 636 manufactured by Omnova was dissolved, and the solution was filtered through a 0.2 μm size filter to prepare a positive resist composition.

[0261] In Tables 1 and 2, each component is as follows. · Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (diacetone alcohol) EL (ethyl lactate) (The values in parentheses in the table are parts by mass of each solvent.) · Acid generator: PAG-1 (see the following structural formula) · Quencher: Q-1 to Q-6 [Chemical formula]

[0262] [EUV Exposure Evaluation] Each resist material shown in Table 1 was spin-coated onto a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content: 43% by mass) was formed to a thickness of 20 nm, and pre-baked at 105 °C for 60 seconds using a hot plate to produce a resist film with a thickness of 50 nm. This was then exposed using an EUV scanner NXE34000 manufactured by ASML (NA 0.33, σ 0.9 / 0.6, quadrupole illumination, mask with a hole pattern having a wafer-level dimension of pitch 46 nm and +20% bias), PEB was performed on a hot plate at the temperature described in Table 1 for 60 seconds, and development was carried out with a 2.38% by mass aqueous TMAH solution for 30 seconds to obtain a hole pattern with a dimension of 23 nm. When the hole dimensions were each 23 nm, the exposure dose was measured and taken as the sensitivity. Also, the dimensions of 50 holes were measured using a length-measuring SEM (CG6300) manufactured by Hitachi, Ltd., and CDU (dimension variation 3σ) was determined. The results are shown in Tables 1 and 2.

[0263]

Table 1

[0264]

Table 2

[0265] From the results in Tables 1 and 2, it was found that the resist composition containing a sulfonium salt of a carboxylic acid containing an iodine atom, a repeating unit having an iodonium salt structure, and a base polymer containing a repeating unit having a sulfonium salt of a sulfonic acid and an iodonium salt satisfies both sufficient sensitivity and dimensional uniformity. In contrast, Comparative Examples 1 to 3 using a resist composition not containing the resist material (base polymer) of the present invention resulted in poor dimensional uniformity.

[0266] This specification includes the following aspects. [1]: A positive resist material comprising a base polymer having a sulfonium salt or iodonium salt of a carboxylic acid bonded as a pendant group to the polymer main chain, wherein the base polymer contains a repeating unit a containing one or more iodine atoms between the polymer main chain and the carboxylate, and the repeating unit a contains either or both of a repeating unit represented by the following general formula (a)-1 and a repeating unit represented by the following general formula (a)-2. A positive resist material characterized by this. [Chemical formula] (In the formula, R A is a hydrogen atom or a methyl group. X 1 is a single bond, an ester group, an ether group, or a sulfonic acid ester group. X 2 is a single bond, or a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms, and may contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. X 3 is a linear or branched alkylene group having 1 to 10 carbon atoms and having 1 to 4 fluorine atoms, and may have one or more selected from an ether group, an ester group, an aromatic group, a double bond, and a triple bond. R 1 are each independently a hydroxy group, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. R 1A are each independently a halogen atom, a hydroxy group, or a linear or branched alkoxy group having 1 to 6 carbon atoms, or an acyloxy group. l is an integer from 0 to 3. m is an integer from 0 to 4, and n is an integer from 0 to 4. However, the anion part of the pendant group contains one or more iodine atoms. R 2 ~R 6 are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a hetero atom. Also, any two of R 2 , R 3 and R 4 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.) [2]: The positive resist material according to [1], wherein the base polymer further contains at least one selected from the repeating units represented by the following formulas (b1) to (b4). [Chemical formula] (In the formula, R A is independently a hydrogen atom or a methyl group. Z 2A is a single bond or an ester bond. Z 2B is a single bond or a divalent group having 1 to 12 carbon atoms, and may contain an ester bond, an ether bond, a lactone ring, a bromine atom or an iodine atom. Z 3 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, -O-Z 31 -, -C(=O)-O-Z 31 - or -C(=O)-NH-Z 31 -. And Z 31 is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms or a phenylene group, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom or a hydroxy group. Rf 1 ~Rf 4 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one is a fluorine atom. R 23 ~R 27 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. Further, R 23 , R 24 and R 25 Any two of them may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.) [3]: The positive resist material according to [2], wherein one or more iodine atoms are contained in the above Z 2B . [4]: The positive resist material according to any one of [1] to [3], further containing a repeating unit c in which a hydrogen atom of either or both of a carboxy group and a phenolic hydroxy group is substituted with an acid labile group. [5]: The positive resist material according to [4], wherein the repeating unit c is at least one selected from a repeating unit c1 represented by the following formula (c1) and a repeating unit c2 represented by the following formula (c2). [Chemical formula] (In the formula, 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 having an ester bond, an ether bond or a lactone ring. Y 2 is a single bond, an ester bond or an amide bond. R 11 and R 12 are acid-labile groups. 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 a linear or branched alkanediyl group having 1 to 6 carbon atoms, and a part of its carbon atoms may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer from 0 to 4.) [6]: The positive resist material according to any one of [1] to [5], wherein the base polymer further contains a repeating unit d 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-. [7]: The positive resist material according to any one of [1] to [6], wherein the weight average molecular weight of the base polymer is in the range of 1000 to 100000. [8]: A positive resist composition, comprising the positive resist material according to any one of [1] to [7]. [9]: The positive resist composition according to [8], further comprising at least one selected from an acid generator, an organic solvent, a quencher, and a surfactant.

[10] : A method for forming a pattern, comprising the steps of forming a resist film on a substrate using a positive resist composition of [8] or [9], exposing the resist film to high-energy rays, and developing the exposed resist film using a developer.

[11] : The method for forming a pattern according to

[10] , wherein the high-energy rays are i-line, KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet light having a wavelength of 3 to 15 nm.

[12] : A polymer compound having a weight average molecular weight in the range of 1,000 to 100,000, which is a copolymer having any one or both of a repeating unit represented by the following general formula (a)-1 and a repeating unit represented by (a)-2, and one or more repeating units selected from the following general formulas (b1) to (b4). [Chemical formula] [Chemical formula] (In the formula, R A is a hydrogen atom or a methyl group. X 1 is a single bond, an ester group, an ether group, or a sulfonic acid ester group. X 2 is a single bond, or a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms, and may contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. X 3 is a linear or branched alkylene group having 1 to 10 carbon atoms and having 1 to 4 fluorine atoms, and may have one or more selected from an ether group, an ester group, an aromatic group, a double bond, and a triple bond. R 1 are each independently a hydroxy group, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. R 1Ais, independently of one another, a halogen atom, a hydroxy group, a linear or branched alkoxy group having 1 to 6 carbon atoms, or an acyloxy group. l is an integer of 0 to 3. m is an integer of 0 to 4, and n is an integer of 0 to 4. However, the anionic part of the pendant group contains one or more iodine atoms. R 2 ~R 6 are, independently of one another, monovalent hydrocarbon groups having 1 to 25 carbon atoms which may contain a hetero atom. Also, any two of R 2 、R 3 and R 4 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. Z 2A is a single bond or an ester bond. Z 2B is a single bond or a divalent group having 1 to 12 carbon atoms, and may contain an ester bond, an ether bond, a lactone ring, a bromine atom or an iodine atom. Z 3 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, -O-Z 31 -, -C(=O)-O-Z 31 - or -C(=O)-NH-Z 31 -, and Z 31 is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms or a phenylene group, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom or a hydroxy group. Rf 1 ~Rf 4 are, independently of one another, a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one is a fluorine atom. R 23 ~R 27 are, independently of one another, monovalent hydrocarbon groups having 1 to 20 carbon atoms which may contain a hetero atom. Also, any two of R 23 、R 24 and R 25 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.)

[0267] Note that the present invention is not limited to the above-described embodiments. The above-described embodiments are illustrative, and any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits the same operational effects is included in the technical scope of the present invention.

Claims

1. A positive resist material comprising a base polymer having a sulfonium salt or iodonium salt of a carboxylic acid bonded as a pendant group to a polymer main chain, wherein the base polymer contains a repeating unit a containing one or more iodine atoms between the polymer main chain and the carboxylate, and the repeating unit a contains either or both of a repeating unit represented by the following general formula (a)-1 and a repeating unit represented by (a)-2. A positive resist material characterized by the above. 【Chemical 1】 (In the formula, R Ａ is a hydrogen atom or a methyl group. X １ is a single bond, an ester group, an ether group, or a sulfonic acid ester group. X ２ is a single bond or a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms, and may contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. X ３ is a linear or branched alkylene group having 1 to 10 carbon atoms and having 1 to 4 fluorine atoms, and may have one or more selected from an ether group, an ester group, an aromatic group, a double bond, and a triple bond. R １ are each independently a hydroxy group, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. R １Ａ are each independently a halogen atom, a hydroxy group, or a linear or branched alkoxy group having 1 to 6 carbon atoms, or an acyloxy group. l is an integer of 0 to 3. m is an integer of 0 to 4, and n is an integer of 0 to 4. However, the anionic part of the pendant group contains one or more iodine atoms. R ２ to R ６ are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a heteroatom. Further, any two of R ２ , R ３ and R ４ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.)

2. The positive resist material according to claim 1, wherein the base polymer further contains at least one selected from the repeating units represented by the following formulas (b1) to (b4). [Chemical 2] (In the formula, R Ａ is each independently a hydrogen atom or a methyl group. Z ２Ａ is a single bond or an ester bond. Z ２Ｂ is a single bond or a divalent group having 1 to 12 carbon atoms, and may contain an ester bond, an ether bond, a lactone ring, a bromine atom or an iodine atom. Z ３ is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, -O-Z ３１ -, -C(=O)-O-Z ３１ - or -C(=O)-NH-Z ３１ -, and Z ３１ is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms or a phenylene group, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom or a hydroxy group. Rf １ to Rf ４ are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one is a fluorine atom. R ２３ to R ２７ are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. Also, any two of R ２３ , R ２４ and R ２５ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.)

3. Said Z ２Ｂ The positive resist material according to claim 2, which is characterized by containing one or more iodine atoms therein.

4. Furthermore, a positive resist material according to claim 1, characterized by containing a repeating unit c in which a hydrogen atom of either or both of a carboxy group and a phenolic hydroxy group is substituted with an acid-labile group.

5. The positive resist material according to claim 4, wherein the repeating unit c is at least one selected from a repeating unit c1 represented by the following formula (c1) and a repeating unit c2 represented by the following formula (c2). 【Chemical Formula 3】 (wherein, R Ａ is, independently of one another, 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 having an ester bond, an ether bond or a lactone ring. Y ２ is a single bond, an ester bond or an amide bond. R １１ and R １２ are acid-labile groups. 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 a linear or branched alkanediyl group having 1 to 6 carbon atoms, and a part of the carbon atoms thereof may be substituted with an ether bond or an ester bond. a is 1 or 2. b is an integer of 0 to 4.).

6. The positive resist material according to claim 5, wherein the base polymer further contains a repeating unit d 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-.

7. The positive resist material according to claim 1, wherein the weight average molecular weight of the base polymer is in the range of 1,000 to 100,000.

8. A positive resist composition comprising the positive resist material according to any one of claims 1 to 7. A positive resist composition characterized by the above.

9. The positive resist composition according to claim 8, further comprising one or more selected from an acid generator, an organic solvent, a quencher, and a surfactant.

10. A pattern forming method comprising: a step of forming a resist film on a substrate using the positive resist composition according to claim 8; a step of exposing the resist film to high energy rays; and a step of developing the exposed resist film using a developer.

11. A pattern forming method comprising: a step of forming a resist film on a substrate using the positive resist composition according to claim 9; a step of exposing the resist film to high energy rays; and a step of developing the exposed resist film using a developer.

12. The pattern forming method according to claim 10, wherein the high energy rays are i-line, KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet light having a wavelength of 3 to 15 nm.

13. A polymer compound having a weight average molecular weight in the range of 1,000 to 100,000, which is a copolymer having any one or both of a repeating unit represented by the following general formula (a)-1 and a repeating unit represented by (a)-2, and one or more repeating units selected from the following general formulas (b1) to (b4). 【Chemical Formula 4】 【Chemical Formula 5】 (wherein R Ａ is a hydrogen atom or a methyl group. X １ is a single bond, an ester group, an ether group, or a sulfonic acid ester group. X ２ is a single bond, or a linear, branched, or cyclic alkyl group having 1 to 12 carbon atoms, and may contain one or more selected from an ester group, an ether group, an amide group, a lactone ring, a sultone ring, and a halogen atom. X ３ is a linear or branched alkylene group having 1 to 10 carbon atoms and having 1 to 4 fluorine atoms, and may have one or more selected from an ether group, an ester group, an aromatic group, a double bond, and a triple bond. R １ are each independently a hydroxy group, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group, an acyloxy group, or a halogen atom other than iodine. R １Ａ are each independently a halogen atom, a hydroxy group, or a linear or branched alkoxy group having 1 to 6 carbon atoms, or an acyloxy group. l is an integer of 0 to 3. m is an integer of 0 to 4, and n is an integer of 0 to 4. However, the anionic part of the pendant group contains one or more iodine atoms. R ２ to R ６ are each independently a monovalent hydrocarbon group having 1 to 25 carbon atoms which may contain a hetero atom. Further, any two of R ２ , R ３ and R ４ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. Z ２Ａ is a single bond or an ester bond. Z ２Ｂ is a single bond or a divalent group having 1 to 12 carbon atoms, and may contain an ester bond, an ether bond, a lactone ring, a bromine atom, or an iodine atom. Z ３ is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, -O-Z ３１ -, -C(=O)-O-Z ３１ -, or -C(=O)-NH-Z ３１ -, and Z ３１ is an alkanediyl group having 1 to 6 carbon atoms, an alkenediyl group having 2 to 6 carbon atoms or a phenylene group, and may contain a carbonyl group, an ester bond, an ether bond, a halogen atom or a hydroxy group. Rf １ ~Rf ４ each independently is a hydrogen atom, a fluorine atom or a trifluoromethyl group, provided that at least one is a fluorine atom. R ２３ ~R ２７ each independently is a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. Further, any two of R ２３ , R ２４ and R ２５ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. )

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