Chemically amplified positive resist composition and resist pattern forming method

Abstract

To provide a chemical amplification positive type resist composition capable of forming a resist film capable of forming a pattern having an extremely high resolution, small in LER, excellent in rectangularity, and suppressed in influence of development loading, and a method of forming a resist pattern.SOLUTION: A chemical amplification positive type resist composition includes a base polymer including: a polymer including an acid-generating unit, a phenolic hydroxyl group-containing unit, a unit in which a phenolic hydroxyl group is protected by an acid-unstable group, and a unit in which a carboxylic group is protected by an acid-unstable group, or a polymer including an acid-generating unit, a phenolic hydroxyl group-containing unit, and a unit in which a phenolic hydroxyl group is protected by an acid-unstable group; and a polymer including an acid-generating unit, a phenolic hydroxyl group-containing unit, and a unit in which a carboxylic group is protected by an acid-unstable group, where the repeating units having aromatic ring skeletons are 60 mol% or more in all repeating units of polymers contained in the base polymer.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a chemically amplified positive resist composition and a resist pattern forming method.

Background Art

[0002] In recent years, with the increasing integration of integrated circuits, finer pattern formation has been required. In the processing of patterns with a size of 0.2 μm or less, chemically amplified resist compositions using an acid as a catalyst are mainly used. At this time, high-energy rays such as ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays (EUV), and electron beams (EB) are used as exposure light sources. In particular, EB lithography, which is used as an ultrafine processing technology, is also indispensable as a method for processing photomask blanks when manufacturing photomasks for semiconductor production.

[0003] Generally, in EB lithography, drawing by EB is performed without using a mask. In the case of a positive type, fine-area EB is sequentially irradiated to the portions other than the regions where the resist film is to be left, and in the case of a negative type, fine-area EB is sequentially irradiated to the regions where the resist film is to be left. That is, since the entire region finely divided on the processing surface is scanned, it takes more time than batch exposure using a photomask, and a highly sensitive resist film is required to avoid reducing throughput. In the processing of photomask blanks, which is a particularly important application, there are those with surface materials such as chromium compound films including chromium oxide formed on the photomask substrate, which are likely to affect the pattern shape of the chemically amplified resist film. In order to maintain high resolution and the shape after etching, it is also regarded as one of the important performances to keep the pattern profile of the resist film rectangular regardless of the type of substrate. In addition, it is also regarded as one of the important performances that the line edge roughness (LER) is small.

[0004] Regarding the control of sensitivity and pattern profile, various improvements have been made depending on the selection and combination of materials used in the resist composition, process conditions, etc. One of these improvements is the suppression of acid diffusion, which has an important impact on the resolution of the resist film. In photomask processing, it is required that the shape of the resulting resist pattern does not change depending on the time from exposure to heating. A major cause of the time-dependent change in the resist pattern shape is the diffusion of the acid generated by exposure. This problem of acid diffusion has been studied extensively because it has a significant impact on sensitivity and resolution not only in photomask processing but also in general resist compositions.

[0005] Patent Document 1 and Patent Document 2 describe examples of suppressing acid diffusion and reducing LER by swelling the acid generated from the acid generator. However, in such acid generators, the suppression of acid diffusion is still insufficient, so the development of an acid generator with less diffusion has been desired.

[0006] Also, Patent Document 3 describes an example of controlling acid diffusion by introducing a repeating unit having a sulfonium structure that generates sulfonic acid upon exposure into a polymer used in the resist composition. Such a method of introducing a repeating unit that generates acid upon exposure into the base polymer to suppress acid diffusion is effective as a method for obtaining a pattern with a small LER. However, there have been cases where the base polymer containing such a repeating unit that generates acid upon exposure has problems with solubility in organic solvents depending on the structure and introduction rate of the unit.

[0007] Polymers having a large amount of aromatic skeletons with acidic side chains, such as polyhydroxystyrene, are useful as base polymers for KrF lithography resist compositions. However, since they exhibit a large absorption for light in the vicinity of a wavelength of 200 nm, they have not been used as base polymers for ArF lithography resist compositions. However, as resist compositions for EB lithography and resist compositions for EUV lithography, which are promising technologies for forming patterns smaller than the processing limit by ArF excimer lasers, they are important materials in terms of obtaining high etching resistance.

[0008] As base polymers for positive resist compositions for EB lithography and resist compositions for EUV lithography, materials that solubilize in an alkaline developer by deprotecting acid-labile groups that mask the acidic functional groups of the phenol side chains of the base polymer using the acid generated by irradiating a photoacid generator with high-energy rays as a catalyst are mainly used. Further, as the acid-labile groups, tertiary alkyl groups, tert-butoxycarbonyl groups, acetal groups, etc. have mainly been used. Here, when using an acid-labile group having a relatively small activation energy required for deprotection, such as an acetal group, although there is an advantage that a highly sensitive resist film can be obtained, if the suppression of the diffusion of the generated acid is insufficient, a deprotection reaction also occurs in the unexposed portion of the resist film, leading to problems such as deterioration of resolution and LER.

[0009] On the one hand, in the development process of photomask manufacturing, it is known that a phenomenon called development loading occurs, where there are differences in the dimensional finishing of patterns between dense and sparse regions on the photomask. That is, due to development loading, a non-uniform distribution occurs in the dimensional finishing of patterns according to the surrounding pattern distribution. The factors include differences in the desorption reaction during acid generation due to the energy difference of EB, and differences in the dissolution rate of the alkali developer in the dense and sparse pattern drawing areas. As one of the improvements, Patent Document 4 describes a method of adjusting the incident dose amount in an EB drawing apparatus to irradiate EB and draw a pattern on a photomask so as to correct development loading. However, the conventional correction method did not sufficiently consider the phenomenon of development loading for correction. For this reason, the conventional correction method had poor correction accuracy for development loading. To solve this problem, methods for improving the drawing method when drawing a resist film and the development method after patterning, as described in Patent Document 5 and Patent Document 6, have been developed, but they are insufficient for uniformly distributing dense and fine patterns in the advanced generation, and improvement of the resist composition has been desired.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0011] The present invention has been made to solve the above problems, and provides a chemically amplified positive resist composition capable of forming a resist film having extremely high resolution, small LER, excellent rectangularity, and capable of suppressing the influence of development loading, and a resist pattern forming method using the chemically amplified positive resist composition.

Means for Solving the Problems

[0012] As a result of intensive studies to achieve the above object, the present inventors have found that by introducing a base polymer having a specific structure into a resist composition, a pattern showing good resolution, pattern shape and LER and suppressing the influence of development loading can be obtained, and thus the present invention has been completed.

[0013] That is, the present invention provides the following chemically amplified positive resist composition and resist pattern forming method. 1. A chemically amplified positive resist composition containing a base polymer protected by an acid-labile group and becoming alkali-soluble by the action of an acid, wherein the base polymer includes a polymer containing an acid-generating unit, a phenolic hydroxy group-containing unit, a unit in which the phenolic hydroxy group is protected by an acid-labile group, and a unit in which the carboxy group is protected by an acid-labile group, or a polymer containing an acid-generating unit, a phenolic hydroxy group-containing unit, and a unit in which the phenolic hydroxy group is protected by an acid-labile group, and a polymer containing an acid-generating unit, a phenolic hydroxy group-containing unit, and a unit in which the carboxy group is protected by an acid-labile group, the acid-generating unit is a repeating unit represented by any of the following formulas (A1) to (A8), the phenolic hydroxy group-containing unit is a repeating unit represented by the following formula (B1), the unit in which the phenolic hydroxy group is protected by an acid-labile group is a repeating unit represented by the following formula (B2), and the unit in which the carboxy group is protected by an acid-labile group is a repeating unit represented by the following formula (B3), A chemically amplified positive resist composition in which the repeating units having an aromatic ring skeleton account for 60 mol% or more of all the repeating units of the polymer contained in the base polymer. [Chemical formula] (In the formula, R A is independently a hydrogen atom or a methyl group. X 1 is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or *-O-X 11 -, *-C(=O)-O-X 11 - or *-C(=O)-NH-X 11 -, and X 11 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. X 2 is a single bond or **-X 21 -C(=O)-O-, and X 21 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom. X 3 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, *-O-X 31 -, *-C(=O)-O-X 31 - or *-C(=O)-NH-X 31 -. X 31 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. * is a bond to the carbon atom of the main chain, and ** is a bond to the oxygen atom in the formula. X 4is a hydrocarbylene group having 1 to 30 carbon atoms which may contain a single bond or a hetero atom. k 1 and k 2 are each independently 0 or 1, provided that when X 4 is a single bond, k 1 and k 2 are 0. R 1 ~R 18 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. Further, R 1 and R 2 may combine with each other to form a ring together with the sulfur atom to which they are attached, and R 3 and R 4 , R 6 and R 7 , or R 9 and R 10 may combine with each other to form a ring together with the sulfur atom to which they are attached. R HF is a hydrogen atom or a trifluoromethyl group. Xa - is a non-nucleophilic counter ion.)

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Advantages of the Invention

[0014] The chemically amplified positive resist composition of the present invention has high resolution, a small LER, and is capable of forming a pattern with a good shape after exposure and suppressing the influence of development loading, and is suitable as a resist composition for forming a resist film sensitive to high-energy rays such as ultraviolet rays, far ultraviolet rays, EB, EUV, X-rays, γ-rays, and synchrotron radiation used for processing semiconductors, photomask blanks, etc. Further, the pattern forming method using the chemically amplified positive resist composition of the present invention can form a pattern with high resolution, a reduced LER, and suppressed influence of development loading, and thus can be suitably used for microfabrication techniques, particularly EUV lithography and EB lithography.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, the present invention will be described in detail. In the following description, depending on the structure represented by a chemical formula, there may be an asymmetric carbon and enantiomers or diastereomers may exist. In that case, those isomers are represented by one formula as a representative. Those isomers may be used alone or as a mixture.

[0016] [Chemically Amplified Positive Resist Composition] The chemically amplified positive resist composition of the present invention contains a base polymer protected by an acid-labile group and rendered alkali-soluble by the action of an acid.

[0017] The base polymer is a polymer containing an acid-generating unit, a phenolic hydroxy group-containing unit, a unit in which the phenolic hydroxy group is protected by an acid-labile group, and a unit in which the carboxy group is protected by an acid-labile group, or a polymer containing an acid-generating unit, a phenolic hydroxy group-containing unit, and a unit in which the phenolic hydroxy group is protected by an acid-labile group, and a polymer containing an acid-generating unit, a phenolic hydroxy group-containing unit, and a unit in which the carboxy group is protected by an acid-labile group.

[0018] The acid generating unit is a repeating unit represented by any one of the following formulas (A1) to (A8) (hereinafter, also referred to as repeating units A1 to A8, respectively). [Chemical formula]

[0019] In formulas (A1) to (A8), R A is each independently a hydrogen atom or a methyl group. X 1 is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or *-O-X 11 -, *-C(=O)-O-X 11 - or *-C(=O)-NH-X 11 -, where X 11 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. X 2 is a single bond or **-X 21 -C(=O)-O-, where X 21 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom. X 3 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, *-O-X 31 -, *-C(=O)-O-X 31 - or *-C(=O)-NH-X 31 -. X 31 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. * is a bond to a carbon atom of the main chain, and ** is a bond to an oxygen atom in the formula. X 4 is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms which may contain a hetero atom. k1 and k 2 is each independently 0 or 1, provided that when X 4 is a single bond, k 1 and k 2 are 0.

[0020] The repeating unit represented by formula (A4) or (A8) is a repeating unit that generates an acid in which the β-position of the sulfonyl group is difluoromethylated when irradiated with high-energy rays such as ultraviolet rays, far ultraviolet rays, EB, EUV, X-rays, γ-rays, and synchrotron radiation. The acid has an acid strength suitable for deprotecting a polymer containing a unit in which a phenolic hydroxy group is protected with an acetal group, a tertiary alkyl group, a tert-butoxycarbonyl group, or the like. Further, when a polymer containing the repeating unit is used as a base polymer of a resist composition, it is possible to appropriately control the movement and diffusion of the generated acid.

[0021] Photoacid generators that generate arenesulfonic acid upon irradiation with high-energy rays are also commonly used for deprotecting polymers containing units in which a phenolic hydroxy group is protected with an acetal group, a tertiary alkyl group, or a tert-butoxycarbonyl group. However, in order to obtain the effects of the present invention, even when an arenesulfonic acid generating unit is introduced as a repeating unit of the base polymer, the base polymer may not dissolve in a solvent due to its low solvent solubility. On the other hand, the polymer containing the repeating unit represented by formula (A4) or (A8) of the present invention has sufficient lipophilicity, so its production and handling are easy, and the preparation of a resist composition is also easy.

[0022] In formulas (A2) and (A6), when X 2 is -X 21 -C(=O)-O-, examples of the hydrocarbylene group which may contain a heteroatom represented by X 21 include, but are not limited to, those shown below.

Chemical formula

[0023] In formulas (A2) and (A6), R HF is a hydrogen atom or a trifluoromethyl group. In repeating units A2 and A6, examples of cases where R HF is a hydrogen atom include those described in JP-A-2010-116550, and examples of cases where R HF is a trifluoromethyl group include those described in JP-A-2010-77404. Examples of repeating units A3 and A7 include those described in JP-A-2012-246265 and JP-A-2012-246426.

[0024] In formulas (A1) and (A5), Xa - is a non-nucleophilic counter ion. Examples of non-nucleophilic counter ions represented by Xa - include those described in JP-A-2010-113209 and JP-A-2007-145797.

[0025] X 4The hydrocarbylene group having 1 to 30 carbon atoms which may contain a hetero atom represented by may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkanediyl groups such as methanediyl group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group; cyclic saturated hydrocarbylene groups such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, adamantanediyl group; arylene groups such as phenylene group, methylphenylene group, ethylphenylene group, n-propylphenylene group, isopropylphenylene group, n-butylphenylene group, isobutylphenylene group, sec-butylphenylene group, tert-butylphenylene group, naphthylene group, methylnaphthylene group, ethylnaphthylene group, n-propylnaphthylene group, isopropylnaphthylene group, n-butylnaphthylene group, isobutylnaphthylene group, sec-butylnaphthylene group, tert-butylnaphthylene group; and groups obtained by combining these.

[0026] Further, some or all of the hydrogen atoms of the hydrocarbylene group may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a part of -CH2- constituting the hydrocarbylene group may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc., and as a result, a hydroxy group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. may be formed.

[0027] Preferred examples of anions of monomers that give repeating units A4 and A8 include, but are not limited to, those shown below. [Chemical formula]

[0028] [Chemical formula]

[0029] In formulas (A1) to (A8), R 1 ~R 18 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom.

[0030] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.

[0031] The hydrocarbyl group having 1 to 20 carbon atoms may be saturated or unsaturated and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, tert-pentyl group, n-pentyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, etc.; 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 having 3 to 20 carbon atoms such as a decanyl group, an adamantyl group, an adamantylmethyl group; aryl groups having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, an anthracenyl group, etc. may be mentioned. Further, part or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, etc. may be interposed between the carbon-carbon bonds of the hydrocarbyl group. As a result, it may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc.

[0032] Also, R 1 and R 2 may combine with each other to form a ring together with the sulfur atom to which they are attached, and R 3 and R 4 , R 6 and R 7 , or R 9 and R 10 may combine with each other to form a ring together with the sulfur atom to which they are attached. Examples of the ring formed at this time include those shown below.

Chemical formula

[0033] In formulas (A2) to (A4), specific structures of the sulfonium cation include, but are not limited to, those shown below.

Chemical formula

[0034]

Chemical formula

[0035] [Chemical]

[0036] [Chemical]

[0037] [Chemical]

[0038] [Chemical]

[0039] [Chemical]

[0040] [Chemical]

[0041] [Chemical]

[0042] [Chemical]

[0043] [Chemical]

[0044] [Chemical]

[0045] [Chemical]

[0046]

Chem.

[0047]

Chem.

[0048]

Chem.

[0049]

Chem.

[0050]

Chem.

[0051]

Chem.

[0052]

Chem.

[0053]

Chem.

[0054]

Chem.

[0055] In formulas (A5) to (A8), specific structures of the iodonium cation include, but are not limited to, those shown below.

Chem.

[0056] [Chemical formula]

[0057] Among the repeating units A1 to A8, the unit preferable for processing the photomask blank is the repeating unit A4 because it has an optimal acid strength in designing the acid-detachable group of the polymer.

[0058] The repeating units A1 to A8 are units that generate an acid upon irradiation with high-energy rays. By including these units in the polymer, it is considered that acid diffusion can be moderately suppressed and a pattern with reduced LER can be obtained. Further, by including these units in the polymer, the phenomenon in which the acid volatilizes from the exposed portion and reattaches to the unexposed portion during baking in a vacuum is suppressed, and it is considered to be effective in reducing LER and reducing shape deterioration due to undesirable film loss in the unexposed portion.

[0059] The repeating units A1 to A8 are preferably introduced in the range of 0.1 to 30 mol% and more preferably in the range of 0.5 to 20 mol% in all the repeating units of the polymer contained in the base polymer. The repeating units A1 to A8 may be used alone or in combination of two or more.

[0060] The phenolic hydroxy group-containing unit is a repeating unit represented by the following formula (B1) (hereinafter, also referred to as repeating unit B1). [Chemical formula]

[0061] In formula (B1), R B is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0062] In formula (B1), R 21is a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. The saturated hydrocarbyl group, and the saturated hydrocarbyl moieties of the saturated hydrocarbylcarbonyloxy group and the saturated hydrocarbyloxy group may be linear, branched, or cyclic, and specific examples thereof include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, pentyl group, hexyl group; cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group; groups obtained by combining these, etc. If the number of carbon atoms is below the upper limit, the solubility in an alkaline developer is good. When a is 2 or more, each R 21 may be the same as or different from each other.

[0063] In formula (B1), Y 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is a bond to a carbon atom of the main chain.

[0064] In formula (B1), A 1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of -CH2- constituting the saturated hydrocarbylene group may be substituted with -O-. The saturated hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl groups having 1 to 10 carbon atoms such as methylene group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, and structural isomers thereof; cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms such as cyclopropanediyl group, cyclobutanediyl group, cyclopentanediyl group, cyclohexanediyl group; groups obtained by combining these, etc.

[0065] In formula (B1), a is an integer satisfying 0 ≦ a ≦ 5 + 2c - b. b is an integer of 1 to 3. c is an integer of 0 to 2.

[0066] Y 1 and A 1 When both are single bonds, preferred examples of the repeating unit B1 include units derived from 3-hydroxystyrene, 4-hydroxystyrene, 5-hydroxy-2-vinylnaphthalene, 6-hydroxy-2-vinylnaphthalene, and the like. Among these, more preferred are repeating units represented by the following formula (B1-1) and the like. [Chemical formula] (In the formula, R B and b are the same as described above.)

[0067] Y 1 When Y is other than a single bond, preferred examples of the repeating unit B1 include, but are not limited to, those shown below. In the following formulas, R B is the same as described above. [Chemical formula]

[0068] [Chemical formula]

[0069] The repeating unit B1 is preferably introduced in the range of 10 to 95 mol% in all the repeating units of the polymer contained in the base polymer, and more preferably in the range of 30 to 85 mol%. However, when at least one of the repeating units represented by formula (B3) and formula (B4) that impart high etching resistance to the polymer used in the present invention described later is included, and the unit has a phenolic hydroxy group as a substituent, the ratio is preferably within the above range including this. The repeating unit B1 may be used alone or in combination of two or more.

[0070] The unit in which the phenolic hydroxy group is protected by an acid-labile group is a repeating unit represented by the following formula (B2) (hereinafter also referred to as repeating unit B2).

Chemical formula

[0071] In formula (B2), R B is the same as described above. R 22 is a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. The saturated hydrocarbyl group, and the saturated hydrocarbyl moieties of the saturated hydrocarbylcarbonyloxy group and the saturated hydrocarbyloxy group may be linear, branched or cyclic, and specific examples thereof include those exemplified in the description of R 21 in formula (B1). When the carbon number is below the upper limit, the solubility in an alkaline developer is good. When d is 2 or more, each R 22 may be the same as or different from each other.

[0072] In formula (B2), Y 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is a bond to a carbon atom of the main chain.

[0073] In formula (B2), A 2 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of -CH2- constituting the saturated hydrocarbylene group may be substituted with -O-. The saturated hydrocarbylene group may be linear, branched or cyclic, and specific examples thereof include those exemplified in the description of A 1 in formula (B1).

[0074] In formula (B2), R 23is an acid-labile group when e is 1, and is a hydrogen atom or an acid-labile group when e is 2 or more, with at least one being an acid-labile group.

[0075] In formula (B2), d is an integer satisfying 0 ≦ d ≦ 5 + 2f - e. e is an integer from 1 to 3. f is an integer from 0 to 2.

[0076] The unit in which the carboxy group is protected by an acid-labile group is a repeating unit represented by the following formula (B3) (hereinafter, also referred to as repeating unit B3).

Chemical formula

[0077] In formula (B3), R B is the same as described above. Y 3 is a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 12 carbon atoms with an ester bond, an ether bond or a lactone ring. R 24 is an acid-labile group.

[0078] R 23 and R 24 As the acid-labile groups represented by, any of those which have been used in a number of known chemically amplified resist compositions and which are eliminated by an acid to give an acidic group are not particularly limited and any of them can be used.

[0079] Repeating unit B2 is one in which the hydrogen atom of the phenolic hydroxy group is substituted with an acid-labile group, and particularly preferably one in which the hydrogen atom of the hydroxy group of hydroxystyrene or hydroxyphenyl (meth) acrylate is substituted with an acid-labile group. Examples of the monomer that gives repeating unit B2 include, but are not limited to, those shown below. In the following formulas, R B and R 23 are the same as described above.

Chemical formula

[0080] Further, the repeating unit B3 is one in which the hydrogen atom of the carboxy group is substituted with an acid-labile group, and in particular, one in which the hydrogen atom of the hydroxy group of (meth)acrylate is substituted with an acid-labile group is preferable. Examples of the monomer that provides the repeating unit B3 include, but are not limited to, those shown below. In the following formula, R B and R 24 are the same as those described above.

Chemical formula

[0081]

Chemical formula

[0082] R 23 and R 24 Examples of the acid-labile group represented by include those described in paragraphs

[0030] to

[0082] of JP-A-2014-219657.

[0083] As the acid-labile group, those represented by the following formulas (AL-1) to (AL-19) are preferable.

Chemical formula

[0084] In formulas (AL-1) to (AL-19), R L1 is each independently a saturated hydrocarbyl group or an aryl group having 6 to 20 carbon atoms. R L2 and R L4 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 20 carbon atoms. R L3 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. n is an integer of 1 to 5.

[0085] When a tertiary hydrocarbyl group is selected as the acid-labile group, a resist film thickness is formed to be, for example, 10 to 100 nm, and even when a fine pattern having a line width of 45 nm or less is formed, it is preferable because it gives a pattern with small LER. As the tertiary hydrocarbyl group, in order to obtain the monomer for polymerization by distillation, it is preferably one having 4 to 18 carbon atoms. Further, as the group bonded to the tertiary carbon atom of the tertiary hydrocarbyl group, a saturated hydrocarbyl group having 1 to 20 carbon atoms which may contain an oxygen atom-containing functional group such as an ether bond or a carbonyl group can be mentioned, and the groups bonded to the tertiary carbon atom may be bonded to each other to form a ring.

[0086] Specific examples of the group bonded to the tertiary carbon atom include a methyl group, an ethyl group, a propyl group, an adamantyl group, a norbornyl group, a tetrahydrofuran-2-yl group, a 7-oxanorboran-2-yl group, a cyclopentyl group, a 2-tetrahydrofuryl group, tricyclo[5.2.1.0 2,6 decyl group, tetracyclo[4.4.0.1 2,5 .1 7,10 dodecyl group, 3-oxo-1-cyclohexyl group can be mentioned.

[0087] Examples of the tertiary hydrocarbyl group include a tert-butyl group, a tert-pentyl group, a 1-ethyl-1-methylpropyl group, a 1,1-diethylpropyl group, a 1,1,2-trimethylpropyl group, a 1-adamantyl-1-methylethyl group, a 1-methyl-1-(2-norbornyl)ethyl group, a 1-methyl-1-(tetrahydrofuran-2-yl)ethyl group, a 1-methyl-1-(7-oxanorbornan-2-yl)ethyl group, a 1-methylcyclopentyl group, a 1-ethylcyclopentyl group, a 1-propylcyclopentyl group, an 1-isopropylcyclopentyl group, a 1-cyclopentylcyclopentyl group, a 1-cyclohexylcyclopentyl group, a 1-(2-tetrahydrofuryl)cyclopentyl group, a 1-(7-oxanorbornan-2-yl)cyclopentyl group, a 1-methylcyclohexyl group, a 1-ethylcyclohexyl group, an 1-isopropylcyclohexyl group, a 1-cyclopentylcyclohexyl group, a 1-cyclohexylcyclohexyl group, a 2-methyl-2-norbornyl group, a 2-ethyl-2-norbornyl group, an 8-methyl-8-tricyclo[5.2.1.0 2,6 decyl group, an 8-ethyl-8-tricyclo[5.2.1.0 2,6 decyl group, a 3-methyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 dodecyl group, a 3-ethyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 dodecyl group, a 3-isopropyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 dodecyl group, a 2-methyl-2-adamantyl group, a 2-ethyl-2-adamantyl group, a 2-isopropyl-2-adamantyl group, a 1-methyl-3-oxo-1-cyclohexyl group, a 1-methyl-1-(tetrahydrofuran-2-yl)ethyl group, a 5-hydroxy-2-methyl-2-adamantyl group, a 5-hydroxy-2-ethyl-2-adamantyl group, a 2-(4-fluorophenyl)-2-propyl group, and the like.

[0088] In addition, the acetal group represented by the following formula (AL-20) is often used as an acid-labile group and is a useful option as an acid-labile group that stably provides a pattern with a relatively rectangular interface between the pattern and the substrate. [Chemical formula]

[0089] In formula (AL-20), R L5 is a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. R L6 is a saturated hydrocarbyl group having 1 to 30 carbon atoms.

[0090] R L5 is appropriately selected according to the design of the sensitivity of the decomposable group to an acid. For example, if the design is to decompose with a strong acid while ensuring relatively high stability, a hydrogen atom is selected. If the design is to increase the sensitivity to pH changes using relatively high reactivity, a linear alkyl group is selected. Although it also depends on the combination with the acid generator and basic compound blended in the resist composition, when a relatively large alkyl group is substituted at the end as R L6 and the solubility change due to decomposition is designed to be large, as R L5 , a hydrocarbyl group in which the carbon bonded to the acetal carbon is a secondary carbon atom is preferable. Examples of R L5 bonded to the acetal carbon by a secondary carbon atom include an isopropyl group, a sec-butyl group, a cyclopentyl group, a cyclohexyl group, and the like.

[0091] Among the above acetal groups, in order to obtain higher resolution, R L6 is preferably a polycyclic alkyl group having 7 to 30 carbon atoms. Further, when R L6 is a polycyclic alkyl group, it is preferable that a bond is formed between the secondary carbon constituting the polycyclic ring structure and the acetal oxygen. When bonded on the secondary carbon atom of the ring structure, compared with when bonded on the tertiary carbon atom, the polymer becomes a stable compound, the storage stability of the resist composition is good, and the resolution does not deteriorate. Also, RL6 Even when compared with the case where it is bonded on a primary carbon atom with a linear alkyl group having 1 or more carbon atoms intervening, the glass transition temperature (Tg) of the polymer is good, and the resist pattern after development does not cause shape defects due to baking.

[0092] Preferred examples of the group represented by formula (AL-20) include, but are not limited to, those shown below. In the following formulas, R L5 is the same as described above.

Chemical formula

[0093] As the repeating unit B2, those represented by the following formula (B2-1) are preferred, and as the repeating unit B3, those represented by the following formula (B3-1) are preferred.

Chemical formula

[0094] The repeating unit B2 is preferably introduced in the range of 2 to 40 mol% in all the repeating units of the polymer contained in the base polymer, and the repeating unit B3 is preferably introduced in the range of 2 to 40 mol% in all the repeating units of the polymer contained in the base polymer. It is preferable that the repeating units B2 and B3 together are introduced in the range of 5 to 60 mol% in all the repeating units of the polymer contained in the base polymer.

[0095] As the design of the base polymer, by mixing two types of acid-labile groups in which a phenolic hydroxy group and a carboxy group are protected by acid-labile groups, while maintaining the pattern rigidity due to the phenol skeleton, the dissolution rate of the exposed part due to the carboxylate skeleton is improved. Therefore, while maintaining good resolution of the exposed part, the dissolution contrast between the exposed part and the unexposed part is optimized, suppressing the influence of development loading, and obtaining a pattern with a small dimensional difference regardless of pattern density. When manufacturing a photomask, since the development conditions are stronger than processing a wafer substrate, it is required to form a pattern with good resolution and a small dimensional difference that suppresses the influence of development loading. Therefore, the chemically amplified positive resist composition of the present invention is particularly optimal for processing a photomask substrate.

[0096] The polymer contained in the base polymer preferably further contains at least one selected from the repeating unit represented by the following formula (C1) (hereinafter also referred to as repeating unit C1), the repeating unit represented by the following formula (C2) (hereinafter also referred to as repeating unit C2), and the repeating unit represented by the following formula (C3).

Chemical formula

[0097] In formulas (C1) and (C2), g and h are each independently an integer of 0 to 4.

[0098] In formulas (C1) and (C2), R 31 and R 32 are each independently a hydroxy group, a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. When g is 2 or more, each R31 may be the same as or different from each other. When h is 2 or more, each R 32 may be the same as or different from each other.

[0099] In formula (C3), R B is the same as described above. i is an integer from 0 to 5. j is an integer from 0 to 2.

[0100] In formula (C3), R 33 is an acetyl group, a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms, a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group or a cyano group, and when j is 1 or 2, it may also be a hydroxy group. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, saturated hydrocarbyloxyhydrocarbyl group and saturated hydrocarbylthiohydrocarbyl group may be linear, branched or cyclic. When i is 2 or more, each R 33 may be the same as or different from each other.

[0101] In formula (C3), Y 4 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is a bond to a carbon atom of the main chain.

[0102] In formula (C3), A 3 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of -CH2- constituting the saturated hydrocarbylene group may be substituted with -O-. The saturated hydrocarbylene group may be linear, branched or cyclic, and specific examples thereof include those similar to those exemplified in the description of A 1 in formula (B1).

[0103] When using the repeating units C1 to C3, in addition to the etching resistance of the aromatic ring, an effect of enhancing the EB irradiation resistance during etching and pattern inspection can be obtained due to the addition of a ring structure to the main chain.

[0104] In order to obtain the effect of improving the etching resistance, the repeating units C1 to C3 are preferably introduced in an amount of 5 mol% or more based on all the repeating units of the polymer contained in the base polymer. Further, the repeating units C1 to C3 are preferably introduced in an amount of 35 mol% or less, more preferably 30 mol% or less, based on all the repeating units constituting the base polymer. If the introduction amount of the repeating units C1 to C3 is 35 mol% or less, there is no risk of development defects, which is preferable. The repeating units C1 to C3 may be used alone or in combination of two or more.

[0105] In all the repeating units of the polymer contained in the base polymer, the content of at least one selected from the repeating unit B1, the repeating unit B2, the repeating unit B3, and the repeating units C1 to C3 is preferably 60 mol% or more, more preferably 70 mol% or more.

[0106] The polymer may contain a commonly used (meth)acrylate unit protected with an acid-labile group or a (meth)acrylate unit having an adhesion group such as a lactone structure or a hydroxy group other than a phenolic hydroxy group. The characteristics of the resist film can be finely adjusted by these repeating units, but these units may not be included.

[0107] Examples of the (meth)acrylate unit having an adhesion group include a repeating unit represented by the following formula (C4) (hereinafter also referred to as repeating unit C4), a repeating unit represented by the following formula (C5) (hereinafter also referred to as repeating unit C5), and a repeating unit represented by the following formula (C6) (hereinafter also referred to as repeating unit C6). These units do not exhibit acidity and can be used as auxiliary units for imparting adhesion to the substrate or adjusting solubility. [Chemical formula]

[0108] In formulas (C4) to (C6), R B is the same as described above. R 34 is -O- or a methylene group. R 35 is a hydrogen atom or a hydroxy group. R 36 is a saturated hydrocarbyl group having 1 to 4 carbon atoms. k is an integer from 0 to 3.

[0109] When these units are included, their content is preferably 0 to 30 mol%, more preferably 0 to 20 mol%, based on all the repeating units constituting the polymer contained in the base polymer. The repeating units C4 to C6 may be used alone or in combination of two or more.

[0110] The base polymer may be a mixture of a polymer containing the repeating units A1 to A8 and a polymer not containing the repeating units A1 to A8. Specifically, it is a polymer containing at least one selected from the repeating unit represented by formula (B1), the repeating unit represented by formula (B2), and the repeating unit represented by formula (B3), and not containing the repeating units represented by formulas (A1) to (A8). At this time, the content of the polymer not containing the repeating units A1 to A8 is preferably 2 to 5,000 parts by mass, more preferably 10 to 1,000 parts by mass, per 100 parts by mass of the polymer containing the repeating units A1 to A8.

[0111] The polymer can be synthesized by copolymerizing each monomer protected with a protecting group, if necessary, by a known method, and then performing a deprotection reaction, if necessary. The copolymerization reaction is not particularly limited, but is preferably radical polymerization or anionic polymerization. For these methods, reference can be made to JP-A-2004-115630.

[0112] The polymer preferably has a weight average molecular weight (Mw) of 1,000 to 50,000, more preferably 2,000 to 20,000. If Mw is 1,000 or more, as is conventionally known, there is no possibility of phenomena such as the head of the pattern becoming round and the resolution decreasing, or the LER deteriorating. On the other hand, if Mw is 50,000 or less, there is no possibility of the LER deteriorating, particularly when forming a pattern with a pattern line width of 100 nm or less. In the present invention, Mw is a polystyrene-equivalent measurement value by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or dimethylformamide (DMF) as a solvent.

[0113] The polymer preferably has a narrow molecular weight distribution (Mw / Mn) of 1.0 to 2.0, preferably 1.0 to 1.9, more preferably 1.0 to 1.8. When the distribution is narrow in this way, foreign matter does not occur on the pattern and the shape of the pattern does not deteriorate after development.

[0114] Also, as the base polymer design, the dissolution rate in an alkali developer is preferably 8 nm / min or less, more preferably 6 nm / min or less, and even more preferably 5 nm / min or less. In the latest generation, when the coating film on the substrate is in the thin film region (100 nm or less), the influence of pattern film loss on alkali development becomes large. If the alkali dissolution rate of the polymer is more than 8 nm / min, the pattern will collapse and it will be impossible to form a fine pattern. In particular, in the production of photomasks where no defects are required, this is significant because the development process has a strong tendency. In the present invention, the dissolution rate of the base polymer in an alkali developer is a value calculated from the film loss amount when a polymer solution (polymer concentration: 16.7% by mass, solvent: propylene glycol monomethyl ether (PGME)) is spin-coated on an 8-inch silicon wafer, baked at 100 °C for 90 seconds to form a film with a thickness of 1,000 nm, and then developed with a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) at 23 °C for 100 seconds.

[0115] [Polymer containing fluorine atoms] The chemically amplified positive resist composition of the present invention shields the mixing of acid from the antistatic film in the process of applying the antistatic film material on the resist to high contrast, chemical flare of acid upon high energy ray irradiation, and suppresses unexpected unnecessary pattern deterioration. For this purpose, it contains at least one selected from the repeating unit represented by the following formula (D3), the repeating unit represented by the following formula (D4), the repeating unit represented by the following formula (D5), and the repeating unit represented by the following formula (D6) (hereinafter, also referred to as repeating units D3, D4, D5, and D6, respectively), and may further contain at least one selected from the repeating unit represented by the following formula (D1) and the repeating unit represented by the following formula (D2) (hereinafter, also referred to as repeating units D1 and D2, respectively), and may contain a fluorine atom-containing polymer. Since the fluorine atom-containing polymer also has the function of a surfactant, it can prevent the reattachment of insoluble substances that may occur during the development process to the substrate, and thus also exerts an effect on development defects. [Chemical formula]

[0116] In formulas (D1) to (D6), R C is, independently of each other, a hydrogen atom or a methyl group. R D is, independently of each other, a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 101 is a hydrogen atom, or a linear or branched hydrocarbyl group having 1 to 5 carbon atoms in which a group containing a heteroatom may be interposed between carbon-carbon bonds. R 102 is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms in which a group containing a heteroatom may be interposed between carbon-carbon bonds. R 103 is a saturated hydrocarbyl group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, and a part of -CH2- constituting the saturated hydrocarbyl group may be substituted with an ester bond or an ether bond. R 104 R 105 R107 and R 108 is, independently of one another, a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. R 106 , R 109 , R 110 and R 111 is, independently of one another, a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms or an acid-labile group, and when R 106 , R 109 , R 110 and R 111 is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be interposed between carbon-carbon bonds. x is an integer of 1 to 3. y is an integer satisfying 0 ≦ y ≦ 5 + 2z - x. z is 0 or 1. m is an integer of 1 to 3. Z 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is a bond to a carbon atom of the main chain. Z 2 is a single bond, -O-, *-C(=O)-O-Z 21 -Z 22 - or *-C(=O)-NH-Z 21 -Z 22 -. Z 21 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. Z 22 is a single bond, an ester bond, an ether bond or a sulfonamide bond. * is a bond to a carbon atom of the main chain. Z 3 is a (m + 1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (m + 1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms.

[0117] R 101 and R 102 Examples of the hydrocarbyl group having 1 to 5 carbon atoms represented by include an alkyl group, an alkenyl group, an alkynyl group and the like, with an alkyl group being preferred. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, an n-pentyl group and the like. Further, a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom or the like may be interposed between carbon-carbon bonds of these groups.

[0118] In formula (D1), -OR 101 is preferably a hydrophilic group. In this case, R 101 is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms in which an oxygen atom is interposed between carbon-carbon bonds, and the like.

[0119] Examples of the repeating unit D1 include, but are not limited to, those shown below. In the following formulas, R C is the same as described above.

Chemical formula

[0120]

Chemical formula

[0121] Z 1 is preferably *-C(=O)-O- or *-C(=O)-NH-. Further, R C is preferably a methyl group. The presence of a carbonyl group in Z 1 improves the ability to trap acids derived from the antistatic film. Also, when R C is a methyl group, a stiffer polymer with a higher glass transition temperature (Tg) is obtained, suppressing the diffusion of acids. As a result, the resist film has good stability over time, and the resolution and pattern shape do not deteriorate.

[0122] Z 21 The saturated hydrocarbylene group having 1 to 10 carbon atoms represented by may be linear, branched, or cyclic. Specific examples thereof include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-1,3-diyl group, a propane-2,2-diyl group, a butane-1,1-diyl group, a butane-1,2-diyl group, a butane-1,3-diyl group, a butane-2,3-diyl group, a butane-1,4-diyl group, a 1,1-dimethylethane-1,2-diyl group, and the like.

[0123] R 103 A saturated hydrocarbyl group having 1 to 20 carbon atoms, in which at least one hydrogen atom represented by is substituted with a fluorine atom, may be linear, branched, or cyclic. Specific examples thereof include, in the description of Formulas (A1) to (A8), R 1 ~R 18 Examples thereof include those in which at least one hydrogen atom of the alkyl group and the cyclic saturated hydrocarbyl group exemplified as the hydrocarbyl group represented by is substituted with a fluorine atom.

[0124] Examples of the repeating unit D2 include, but are not limited to, those shown below. In the following formulas, R C is the same as described above.

Chemical formula

[0125]

Chemical formula

[0126]

Chemical formula

[0127]

Chemical formula

[0128] R 104 、R 105 、R 107 and R 108Examples of the saturated hydrocarbyl group having 1 to 10 carbon atoms represented by include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, and n-decyl group; and cyclic saturated hydrocarbyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, adamantyl group, and norbornyl group. Among these, the saturated hydrocarbyl group having 1 to 6 carbon atoms is preferable.

[0129] R 106 , R 109 , R 110 and R 111 Examples of the hydrocarbyl group having 1 to 15 carbon atoms represented by include alkyl group, alkenyl group, alkynyl group, etc., and an alkyl group is preferable. Examples of the alkyl group include, in addition to those described above, n-undecyl group, n-dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc. Further, examples of the fluorinated hydrocarbyl group include a group in which some or all of the hydrogen atoms bonded to the carbon atoms of the above-described hydrocarbyl group are substituted with fluorine atoms.

[0130] Z 3 Examples of the (m + 1)-valent hydrocarbon group having 1 to 20 carbon atoms and the (m + 1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by include groups in which m hydrogen atoms are further removed from the above-described hydrocarbyl group or fluorinated hydrocarbyl group, etc.

[0131] Specific examples of the repeating units D3 to D6 include, but are not limited to, those shown below. In the following formulas, R D is the same as described above.

[0132]

Chemical formula

[0133]

Chemical formula

[0134] [Chemical formula]

[0135] The content of repeating unit D1 and / or D2 is preferably 5 to 85 mol%, more preferably 15 to 80 mol%, based on all the repeating units of the fluorine atom-containing polymer. The content of repeating units D3 to D6 is preferably 15 to 95 mol%, more preferably 20 to 85 mol%, based on all the repeating units of the fluorine atom-containing polymer. The repeating units D1 to D6 may be used alone or in combination of two or more.

[0136] The fluorine atom-containing polymer may contain other repeating units other than the repeating units described above. Examples of such repeating units include those described in paragraphs

[0046] to

[0078] of JP-A-2014-177407. When the fluorine atom-containing polymer contains other repeating units, the content is preferably 50 mol% or less based on all the repeating units of the fluorine atom-containing polymer.

[0137] The fluorine atom-containing polymer can be synthesized by copolymerizing each monomer protected with a protecting group, if necessary, by a known method, and then performing a deprotection reaction, if necessary. The copolymerization reaction is not particularly limited, but is preferably radical polymerization or anionic polymerization. For these methods, reference can be made to JP-A-2004-115630.

[0138] The Mw of the fluorine atom-containing polymer is preferably from 2,000 to 50,000, more preferably from 3,000 to 20,000. When Mw is less than 2,000, it may promote the diffusion of the acid, and the resolution and stability over time may be impaired. When Mw is too large, the solubility in the solvent becomes small, and coating defects may occur. Further, the fluorine atom-containing polymer preferably has an Mw / Mn of from 1.0 to 2.2, more preferably from 1.0 to 1.7.

[0139] When the chemically amplified positive resist composition of the present invention contains the fluorine atom-containing polymer, the content thereof is preferably from 0.01 to 30 parts by mass, more preferably from 0.1 to 20 parts by mass, and still more preferably from 0.5 to 10 parts by mass with respect to 80 parts by mass of the base polymer.

[0140] [Organic solvent] The chemically amplified positive resist composition of the present invention may contain an organic solvent. The organic solvent is not particularly limited as long as it can dissolve each component. Examples of such organic solvents include ketones such as cyclohexanone and methyl-2-n-pentyl ketone described in paragraphs

[0144] to

[0145] of JP-A-2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; ethers such as PGME, 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 (PGMEA), propylene glycol monoethyl ether acetate, ethyl lactate (EL), 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. When an acetal-based acid-labile group is used, a high-boiling alcohol-based solvent, specifically, diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, 1,3-butanediol, etc. can be added to accelerate the deprotection reaction of the acetal.

[0141] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, PGME, cyclohexanone, EL, γ-butyrolactone, and mixed solvents thereof are preferred.

[0142] When the chemically amplified positive resist composition of the present invention contains the organic solvent, the content is preferably 200 to 10,000 parts by mass, more preferably 400 to 5,000 parts by mass, per 80 parts by mass of the base polymer. The organic solvent may be used alone or in combination of two or more.

[0143] [Photoacid generator] The chemically amplified positive resist composition of the present invention may contain a photoacid generator (hereinafter, also referred to as an additive photoacid generator). The photoacid generator is not particularly limited as long as it is a compound that generates an acid upon irradiation with high-energy rays. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, and the like.

[0144] Specific examples of the photoacid generator include nonafluorobutanesulfonate, partially fluorinated sulfonates described in paragraphs

[0247] to

[0251] of JP-A-2012-189977, partially fluorinated sulfonates described in paragraphs

[0261] to

[0265] of JP-A-2013-101271, those described in paragraphs

[0122] to

[0142] of JP-A-2008-111103, and those described in paragraphs

[0080] to

[0081] of JP-A-2010-215608. Among these specific examples, arylsulfonate type or alkanesulfonate type photoacid generators are preferred because they generate an acid with an appropriate strength to deprotect the acid-labile group of the repeating unit represented by formula (B2) or (B3).

[0145] As such a photoacid generator, a compound having a sulfonium anion with the structure shown below is preferred. Examples of the counter cation include those described above as specific examples of the sulfonium cation in formulas (A2) to (A4). [Chemical formula]

[0146] [Chemical formula]

[0147] [Chemical formula]

[0148] [Chemical formula]

[0149] [Chemistry]

[0150] [Chemistry]

[0151] [Chemistry]

[0152] The acid generated by the photoacid generator preferably has a pKa of -2.0 or higher. The upper limit of the pKa is preferably 2.0. The pKa value is calculated using the pKa DB in the software ACD / Chemsketch ver:9.04 manufactured by Advanced Chemistry Development, Inc.

[0153] When the chemically amplified positive resist composition of the present invention contains an additive photoacid generator, its content is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, based on 80 parts by mass of the base polymer. The additive photoacid generator may be used alone or in combination of two or more.

[0154] [Quencher] The chemically amplified positive resist composition of the present invention preferably contains a quencher. 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, the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, a sulfonic acid ester bond, or compounds having a carbamate group described in Japanese Patent No. 3790649 are preferable. Preferred examples include tris[2-(methoxymethoxy)ethyl]amine, tris[2-(methoxymethoxy)ethyl]amine N-oxide, dibutylaminobenzoic acid, morpholine derivatives, imidazole derivatives, and the like. 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.

[0155] In addition, examples of the quencher include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of 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, but 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. Carboxylic acids in which the α-position is not fluorinated hardly cause a deprotection reaction and thus function as a quencher.

[0156] Examples of the onium salts of carboxylic acids in which the α-position is not fluorinated include those represented by the following formula (F1). [Chemical formula]

[0157] In formula (F1), R 201 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hydrogen atom or a hetero atom, provided that the hydrogen atom bonded to the carbon atom at the α-position of the carboxy group is excluded from those substituted with a fluorine atom or a fluoroalkyl group.

[0158] The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 40 carbon atoms such as methyl group, ethyl group, 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, etc.; cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms such as cyclopentyl group, cyclohexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylbutyl group, norbornyl group, tricyclo[5.2.1.0 2,6 decanyl group, adamantyl group, adamantylmethyl group, etc.; alkenyl groups having 2 to 40 carbon atoms such as vinyl group, allyl group, propenyl group, butenyl group, hexenyl group, etc.; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 40 carbon atoms such as cyclohexenyl group, etc.; aryl groups having 6 to 40 carbon atoms such as phenyl group, naphthyl group, alkylphenyl group (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-n-butylphenyl group, etc.), dialkylphenyl group (2,4-dimethylphenyl group, 2,4,6-triisopropylphenyl group, etc.), alkylnaphthyl group (methylnaphthyl group, ethylnaphthyl group, etc.), dialkylnaphthyl group (dimethylnaphthyl group, diethylnaphthyl group, etc.), etc.; aralkyl groups having 7 to 40 carbon atoms such as benzyl group, 1-phenylethyl group, 2-phenylethyl group, etc.

[0159] In addition, some of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms. As a result, it may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. Examples of the hydrocarbyl group containing a heteroatom include heteroaryl groups such as thienyl group; alkoxyphenyl groups such as 4-hydroxyphenyl group, 4-methoxyphenyl group, 3-methoxyphenyl group, 2-methoxyphenyl group, 4-ethoxyphenyl group, 4-tert-butoxyphenyl group, 3-tert-butoxyphenyl group, etc.; alkoxynaphthyl groups such as methoxynaphthyl group, ethoxynaphthyl group, n-propoxynaphthyl group, n-butoxynaphthyl group, etc.; dialkoxynaphthyl groups such as dimethoxynaphthyl group, diethoxynaphthyl group, etc.; aryloxoalkyl groups such as 2-aryl-2-oxoethyl groups such as 2-phenyl-2-oxoethyl group, 2-(1-naphthyl)-2-oxoethyl group, 2-(2-naphthyl)-2-oxoethyl group, etc.

[0160] In formula (F1), Mq + is an onium cation. As the onium cation, a sulfonium cation, an iodonium cation or an ammonium cation is preferable, and a sulfonium cation or an iodonium cation is more preferable. Examples of the sulfonium cation include those similar to those exemplified as the sulfonium cation in formulas (A2) to (A4). Examples of the iodonium cation include those similar to those exemplified as the iodonium cation in formulas (A5) to (A8).

[0161] Examples of the anion of the salt represented by formula (F1) include, but are not limited to, those shown below.

Chemical formula

[0162]

Chem.

[0163]

Chem.

[0164] As the quencher, a sulfonium salt of a carboxylic acid containing an iodinated benzene ring represented by the following formula (F2) can also be preferably used.

Chem.

[0165] In formula (F2), R 301 is a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms, in which part or all of hydrogen atoms may be substituted by halogen atoms, or -N(R 301A )-C(=O)-R 301B or -N(R 301A )-C(=O)-O-R 301B . R 301A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 301B is a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms.

[0166] In formula (F2), x is an integer of 1 to 5. y is an integer of 0 to 3. z is an integer of 1 to 3. L 1is a single bond or a (z + 1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate group, a halogen atom, a hydroxy group, and a carboxy group. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, and saturated hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When y and / or z is 2 or more, each R 301 may be the same as or different from each other.

[0167] In formula (F2), R 302 , R 303 and R 304 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 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 a hydroxy group, a carboxy group, a halogen atom, an oxo group, a cyano group, a nitro 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 302 and R 303 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

[0168] Specific examples of the compound represented by formula (F2) include those described in JP-A-2017-219836. The compound represented by formula (F2) has high absorption, a high sensitizing effect, and a high acid diffusion control effect.

[0169] As the quencher, a nitrogen atom-containing carboxylate compound represented by the following formula (F3) can also be used. [Chemistry]

[0170] In formula (F3), R 401 ~R 404 are each independently a hydrogen atom, -L 2 -CO2 - , or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. R 401 and R 402 and R 402 and R 403 and, or R 403 and R 404 may combine with each other to form a ring together with the carbon atom to which they are attached. L 2 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a single bond or a heteroatom. R 405 is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom.

[0171] In formula (F3), ring R is a ring having 2 to 6 carbon atoms containing the carbon atoms and nitrogen atoms in the formula, and part or all of the hydrogen atoms attached to the carbon atoms of the ring are a hydrocarbyl group having 1 to 20 carbon atoms, or -L 2 -CO2 - and may be substituted, and part of the carbon atoms of the ring may be substituted with a sulfur atom, an oxygen atom or a nitrogen atom. The ring may be an alicyclic ring or an aromatic ring, and is preferably a 5-membered ring or a 6-membered ring. Specific examples thereof include a pyridine ring, a pyrrole ring, a pyrrolidine ring, a piperidine ring, a pyrazole ring, an imidazoline ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, an imidazoline ring, an oxazole ring, a thiazole ring, a morpholine ring, a thiadiazine ring, a triazole ring, etc.

[0172] The onium carboxylate salt represented by formula (F3) has at least one -L 2 -CO2 - group. That is, at least one of R 401 ~R 404 is -L 2 -CO2 -and / or at least one of the hydrogen atoms bonded to the carbon atoms of ring R is -L 2 -CO2 - and is substituted therewith.

[0173] In formula (F3), Q + is a sulfonium cation, an iodonium cation or an ammonium cation, with the sulfonium cation being preferred. Examples of the sulfonium cation include the same ones as those exemplified as the cations in formulas (A2) to (A4).

[0174] Examples of the anion of the compound represented by formula (F3) include, but are not limited to, the following.

Chemical formula

[0175]

Chemical formula

[0176]

Chemical formula

[0177]

Chemical formula

[0178]

Chemical formula

[0179]

Chemical formula

[0180] In addition, as the quencher, a betaine-type compound of a weak acid can also be used. Specific examples thereof include, but are not limited to, the following. [Chemistry]

[0181] As the quencher, a polymer-type quencher described in JP-A-2008-239918 can be further mentioned. By orienting on the surface of the resist film, the rectangularity of the resist pattern is improved. The polymer-type quencher also has an effect of preventing film loss of the pattern and rounding of the pattern top when a protective film for liquid immersion exposure is applied.

[0182] When the chemically amplified positive resist composition of the present invention contains a quencher, its content is preferably 0 to 50 parts by mass, more preferably 0.1 to 40 parts by mass, based on 80 parts by mass of the base polymer. The quencher may be used alone or in combination of two or more.

[0183] [Surfactant] The chemically amplified positive resist composition of the present invention may contain a commonly used surfactant in order to improve the coatability on the substrate. When using a surfactant, many are known as described in a number of examples in JP-A-2004-115630, and they can be selected with reference to them. The content of the surfactant is preferably 0 to 5 parts by mass based on 80 parts by mass of the base polymer. When the fluorine atom-containing polymer is contained in the chemically amplified positive resist composition of the present invention, since the fluorine atom-containing polymer also serves as a surfactant, the surfactant may not be contained.

[0184] As for the design of the chemically amplified positive resist composition of the present invention, the dissolution rate of the overexposed portion of the resulting resist film in an alkaline developer is preferably 50 nm / sec or more, more preferably 70 nm / sec or more, from the viewpoint of improving development loading. By being 50 nm / sec or more, even if there are differences in pattern layout in a dense / non-dense pattern, it can be uniformly dissolved in an alkaline developer, and line width fluctuations can be reduced. The overexposed portion dissolution rate in the present invention is obtained by spin-coating the chemically amplified positive resist composition of the present invention on an 8-inch silicon wafer, baking at 110°C for 60 seconds to form a resist film with a film thickness of 90 nm, exposing with KrF excimer laser light at an energy amount at which the deprotection reaction of the polymer is completed, baking at 110°C for 60 seconds, and then calculating from the film loss amount when developing at 23°C with a 2.38 mass% TMAH aqueous solution using a resist development analyzer.

[0185] Also, the dissolution rate of the unexposed portion of the resist film obtained from the chemically amplified positive resist composition of the present invention in an alkaline developer is preferably 10 nm / min or less, more preferably 8 nm / min or less, still more preferably 6 nm / min or less. When the resist film is in the thin film region (100 nm or less), the influence of pattern film loss in an alkaline developer becomes large. If the dissolution rate of the unexposed portion is greater than 10 nm / min, the pattern will collapse and fine pattern formation will be impossible. In particular, in photomask fabrication where no defects are required, it is remarkable because the development process has a strong tendency. The unexposed portion dissolution rate is a value calculated from the film loss amount when developing at 23°C for 80 seconds with a 2.38 mass% TMAH aqueous solution after spin-coating the chemically amplified positive resist composition of the present invention on a 6-inch silicon wafer, baking at 110°C for 240 seconds to form a resist film with a film thickness of 80 nm.

[0186] [Resist Pattern Formation Method] The resist pattern forming method of the present invention includes a step of forming a resist film on a substrate using the chemically amplified positive resist composition described above, a step of irradiating the resist film with a high-energy ray to form a pattern (i.e., a step of exposing the resist film with a high-energy ray), and a step of developing the resist film irradiated with the pattern using an alkaline developer.

[0187] As the substrate, for example, a substrate for integrated circuit manufacturing (Si, SiO, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflection film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, Si, SiO, SiO2, SiON, SiONC, CoTa, NiTa, TaBN, SnO2, etc.) can be used. The chemically amplified positive resist composition is applied onto the substrate by a method such as spin coating so that the film thickness becomes 0.03 to 2 μm, and this is prebaked on a hot plate, preferably at 60 to 150 °C for 1 to 20 minutes, more preferably at 80 to 140 °C for 1 to 10 minutes, to form a resist film.

[0188] Next, the resist film is exposed using a high-energy ray to irradiate a pattern. Examples of the high-energy ray include ultraviolet ray, far ultraviolet ray, excimer laser light (KrF, ArF, etc.), EUV, X-ray, γ-ray, synchrotron radiation, EB, etc. In the present invention, it is preferable to perform exposure using EUV or EB.

[0189] When using ultraviolet ray, far ultraviolet ray, excimer laser light, EUV, X-ray, γ-ray or synchrotron radiation as the high-energy ray, a mask for forming a target pattern is used, and the exposure amount is preferably 1 to 500 mJ / cm 2 、more preferably 10 to 400 mJ / cm 2 and irradiated so as to be. When using EB, for directly forming a target pattern, the exposure amount is preferably 1 to 500 μC / cm 2 、more preferably 10 to 400 μC / cm 2 and irradiated so as to be.

[0190] In addition to the normal exposure method, immersion exposure, in which the space between the mask and the resist is filled with a liquid, can also be used in some cases. In that case, it is also possible to use a protective film that is insoluble in water.

[0191] Next, post-exposure baking (PEB) is performed on a hot plate, preferably at 60 to 150°C for 1 to 20 minutes, more preferably at 80 to 140°C for 1 to 10 minutes.

[0192] Thereafter, a developing solution of an alkaline aqueous solution such as 0.1 to 5% by mass, preferably 2 to 3% by mass of TMAH is used, and development is carried out by a conventional method such as the dip method, the puddle method, or the spray method, preferably for 0.1 to 3 minutes, more preferably for 0.5 to 2 minutes, to form a target pattern on the substrate.

[0193] The chemically amplified positive resist composition of the present invention is useful because it can particularly form a pattern with good resolution and a small LER. In addition, since it is difficult to achieve good adhesion of the resist pattern, the chemically amplified positive resist composition of the present invention is particularly useful for forming a pattern on a substrate having a surface made of a material that is prone to pattern peeling or pattern collapse. Examples of such a substrate include a substrate having a chromium compound containing one or more light elements selected from metallic chromium, oxygen, nitrogen, and carbon sputter-deposited on the outermost surface, SiO, SiO x , a substrate containing a tantalum compound, a molybdenum compound, a cobalt compound, a nickel compound, a tungsten compound, or a tin compound in the outermost layer, and the like. The chemically amplified positive resist composition of the present invention is particularly useful for forming a pattern using a photomask blank as the substrate. At this time, the photomask blank may be a transmissive type or a reflective type.

[0194] According to the resist pattern forming method of the present invention, even when a substrate (for example, a photomask blank) whose outermost surface is made of a material that easily affects the resist pattern shape, such as a material containing chromium, silicon, or tantalum, is used, a pattern with high resolution and small dimensional differences that is independent of pattern density and suppresses the influence of development loading can be obtained.

Example

[0195] Hereinafter, the present invention will be specifically described by showing synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples. The copolymer composition ratio is a molar ratio, and Mw is the polystyrene-reduced weight average molecular weight measured by GPC.

[0196] [1] Synthesis of sulfonium salt [Synthesis Example 1] Synthesis of sulfonium salt PM-1

Chemical formula

[0197] Sodium 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropane-1-sulfonate was synthesized according to the method described in JP-A-2010-215608. To 132 g of an aqueous solution containing the obtained sodium 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropane-1-sulfonate (equivalent to 0.1 mol of sodium 3,3,3-trifluoro-2-hydroxy-2-trifluoromethylpropane-1-sulfonate), 200 g of methylene chloride and 20.4 g of benzyltrimethylammonium chloride were added and stirred for 30 minutes. Liquid separation, extraction, and washing with water of the stirred aqueous solution were performed, and then the organic layer was concentrated. Methyl isobutyl ketone was added, and concentration was performed again. Diisopropyl ether was added to the concentrated solution for recrystallization, and the precipitated solid was recovered and dried under reduced pressure to obtain a benzyltrimethylammonium salt. To the obtained benzyltrimethylammonium salt, 15.0 g of triethylamine and 200 g of methylene chloride were added. To this mixed solution, 11.5 g of methacryloyl chloride was added under ice cooling, and after stirring at room temperature overnight, 100 g of water was added to the reaction solution to stop the reaction. The quenched reaction solution was separated, and an aqueous solution of triphenylsulfonium chloride was added to the extracted organic layer, followed by stirring for 30 minutes, separation, and washing with water. Thereafter, the organic layer was concentrated, methyl isobutyl ketone was added, and concentration was performed again. Diisopropyl ether was added to the concentrated solution for recrystallization, and the precipitated solid was recovered and dried under reduced pressure to obtain the target product, triphenylsulfonium 2-(methacryloyloxy)-3,3,3-trifluoro-2-trifluoromethylpropane-1-sulfonate (PM-1) as a white solid (yield 85%).

[0198] [2] Synthesis of polymer [Synthesis Example 2-1] Synthesis of polymer P-1 Under a nitrogen atmosphere, 25.5 g of a 50.0 mass% PGMEA solution of 4-hydroxystyrene, 9.3 g of ethyl cyclopentyl methacrylate, 12.7 g of 1-(1-methylcyclopentyloxy)-4-vinylbenzene, 17.5 g of PM-1, 4.1 g of dimethyl-2,2'-azobis-(2-methylpropionate) (manufactured by Fujifilm Wako Pure Chemical Corporation, trade name V-601), and 24 g of γ-butyrolactone and 30 g of PGMEA as solvents were added to a 200 mL dropping cylinder to prepare a solution. Furthermore, 40 g of γ-butyrolactone was added to another 300 mL polymerization flask under a nitrogen atmosphere, and while heating to 80°C, the prepared solution was dropped over 4 hours. After completion of dropping, the mixture was stirred for 18 hours while maintaining the temperature at 80°C, and then cooled to room temperature. When the obtained polymerization solution was dropped into 400 g of diisopropyl ether, a solid precipitated. The solution in which the solid had precipitated was allowed to stand, and the diisopropyl ether was removed by decantation. The precipitated solid was dissolved in 100 g of acetone. This acetone solution was dropped into 400 g of diisopropyl ether, and the precipitated solid was filtered off. The solid obtained by filtration was dissolved again in 100 g of acetone, and this acetone solution was dropped into 400 g of water, and the precipitated solid was filtered off. Thereafter, the solid obtained by filtration was dried at 40 °C for 40 hours to obtain 35 g of polymer P-1 as a white solid. The obtained polymer P-1 was 1 1H-NMR, 13 When measured by 13C-NMR and GPC, the following analysis results were obtained. [Chemical formula]

[0199] [Synthesis Examples 2-2 to 2-58, Comparative Synthesis Examples 1-1 to 1-2] Polymers P-2 to P-58, Comparative Polymers cP-1 to cP-2 Polymers P-2 to P-58 and comparative polymers cP-1 to cP-2 shown in Tables 1 to 3 below were synthesized in the same manner as in Synthesis Example 2-1, except that the types and mixing ratios of the respective monomers were changed. In Tables 1 to 3 below, the introduction ratio indicates the molar ratio.

[0200] [Table 1]

[0201] [Table 2]

[0202] [Table 3]

[0203] In addition, the structures of the repeating units introduced into the polymer are shown below. [Chemical formula]

[0204] [Chemical]

[0205] [Chemical]

[0206] [Chemical]

[0207] [Chemical]

[0208] [Chemical]

[0209] The dissolution rate of the polymer in an alkaline developer was calculated by spin-coating a polymer solution (polymer concentration: 16.7% by mass, solvent: PGME) on an 8-inch silicon wafer, baking at 100°C for 90 seconds to form a film with a thickness of 1,000 nm, developing with a 2.38% by mass aqueous TMAH solution at 23°C for 100 seconds, and measuring the film thickness reduction. As a result, the dissolution rates of polymers P-1 to P-58 and comparative polymers cP-1 to cP-2 were 5 nm / min or less.

[0210] [Synthesis Examples 3-1 to 3-11] Synthesis of Polymers AP-1 to AP-11 Polymers AP-1 to AP-11 were synthesized in the same manner as in Synthesis Example 2-1, except that the raw material compounds used were changed. [Chemical]

[0211] [Chemical]

[0212] [Chemical formula]

[0213] The dissolution rate of polymers AP-1 to AP-11 was 5 nm / min or less.

[0214] [3] Preparation of chemically amplified positive resist composition [Examples 1-1 to 1-90, Comparative Examples 1-1 to 1-3] Each component was dissolved in an organic solvent with the compositions shown in Tables 4 to 8 below, and the resulting solution was filtered through a 0.02 μm size UPE filter to prepare a chemically amplified positive resist composition. The organic solvent is a mixed solvent of 340 parts by mass of PGMEA, 1,700 parts by mass of EL, and 1,360 parts by mass of PGME. In addition, 0.075 parts by mass of FC-4430 (manufactured by 3M) was added to the organic solvent as a surfactant.

[0215] [Table 4]

[0216] [Table 5]

[0217] [Table 6]

[0218] [Table 7]

[0219] [Table 8]

[0220] In Tables 4 to 8, the structures of quenchers Q-1 to Q-3, photoacid generators PAG-A to PAG-C, and polymers D-1 to D-5 are as follows. [Chemical formula]

[0221] [Chemical formula]

[0222] [Chemical formula]

[0223] [4] EB Lithography Evaluation [Examples 2-1 to 2-90, Comparative Examples 2-1 to 2-3] Each chemically amplified positive resist composition (R-1 to R-90, CR-1 to CR-3) was spin-coated onto a photomask blank with a 152 mm square top surface made of chromium using ACT-M (manufactured by Tokyo Electron Limited), and pre-baked on a hot plate at 110 °C for 600 seconds to form a resist film with a thickness of 80 nm. The film thickness of the obtained resist film was measured using an optical measuring instrument, Nanoscope (manufactured by Nanometrics, Inc.). The measurement was performed at 81 locations in the plane of the blank substrate excluding the outer edge portion from the outer circumference to 10 mm inside, and the film thickness average value and the film thickness range were calculated.

[0224] Furthermore, exposure was performed using an electron beam exposure apparatus (EBM-5000plus manufactured by NuFlare Technology Inc., acceleration voltage 50 kV), PEB was applied at 110 °C for 600 seconds, and development was carried out with a 2.38 mass% TMAH aqueous solution to obtain a positive pattern.

[0225] The obtained resist pattern was evaluated as follows. The mask blank with the fabricated pattern was observed with an aerial SEM (scanning electron microscope), and the exposure dose that resolves a 200 nm 1:1 line and space (LS) at 1:1 was defined as the optimum exposure dose (μC / cm2 ) and defined the minimum dimension at the exposure dose for resolving 200 nm LS at a 1:1 ratio as the resolution (limiting resolution), and measured the edge roughness (LER) of the 200 nm LS by SEM. For the development loading evaluation, on the substrate surface, the exposure dose (μC / cm 2 ) at which a 200 nm LS pattern formed at a ratio of 1:1 and a 200 nm LS pattern with dummy patterns of densities 15%, 25%, 33%, 45%, 50%, 55%, 66%, 75%, 85%, and 95% arranged around the pattern were formed at a ratio of 1:1 were used to measure the space part dimensions of the 200 nm LS patterns by SEM, and the difference in dimensions between the sparse and dense patterns was compared. Regarding the pattern shape, it was visually determined whether it was rectangular or not.

[0226] The dissolution rate of the overexposed part was calculated by spin-coating a resist solution on an 8-inch silicon wafer, baking it at 110 °C for 60 seconds to form a resist film with a thickness of 90 nm, then exposing it with KrF excimer laser light at the exposure dose (mJ / cm 2 ) for resolving 200 nm 1:1 line and space (LS) at a 1:1 ratio, baking it at 110 °C for 60 seconds, and then developing it at 23 °C with a 2.38 mass% TMAH aqueous solution using a resist development analyzer (RDA-800 manufactured by Resotec Japan Co., Ltd.). The results are shown in Tables 9 to 12.

[0227]

Table 9

[0228]

Table 10

[0229]

Table 11

[0230]

Table 12

[0231] All of the chemically amplified positive resist compositions (R-1 to R-90) of the present invention exhibited good resolution, LER, and pattern rectangularity, and showed values with suppressed development loading. On the other hand, in the resist compositions of the comparative examples (CR-1 to CR-3), in CR-1, the dissolution rate of the overexposed portion was too small, so the suppression of development loading was insufficient. In CR-2 and CR-3, the design of the base polymer was insufficient. Although the development loading was good, it was impossible to achieve both resolution, LER, and pattern rectangularity. This is because, as the design of the base polymer, specifically, an acid diffusion suppressing effect can be obtained by using a PAG-bound polymer skeleton, and by combining a phenolic acid-labile group and an acrylate-based acid-labile group, the pattern shape is optimized by the phenolic unit, and the dissolution rate of the exposed portion by the acrylate-based is optimized. It is considered that resolution, LER, pattern rectangularity, and suppression of development loading have been achieved. The resist pattern forming method using the chemically amplified positive resist composition of the present invention is useful for photolithography in semiconductor device manufacturing, particularly in the processing of transmissive and reflective photomask blanks.

Claims

1. A chemically amplified positive resist composition comprising a base polymer protected by an acid-labile group and becoming alkali-soluble by the action of an acid, and a fluorine atom-containing polymer, wherein the base polymer comprises a polymer containing an acid-generating unit, a phenol hydroxy group-containing unit, a unit in which the phenol hydroxy group is protected by an acid-labile group, and a unit in which the carboxy group is protected by an acid-labile group, or a polymer containing an acid-generating unit, a phenol hydroxy group-containing unit, and a unit in which the phenol hydroxy group is protected by an acid-labile group, and a polymer containing an acid-generating unit, a phenol hydroxy group-containing unit, and a unit in which the carboxy group is protected by an acid-labile group, wherein the acid-generating unit is a repeating unit represented by any one of the following formulas (A1) to (A8), the phenol hydroxy group-containing unit is a repeating unit represented by the following formula (B1), the unit in which the phenol hydroxy group is protected by an acid-labile group is a repeating unit represented by the following formula (B2), and the unit in which the carboxy group is protected by an acid-labile group is a repeating unit represented by the following formula (B3), in all the repeating units of the polymer contained in the base polymer, the repeating unit having an aromatic ring skeleton is 60 mol% or more, the fluorine atom-containing polymer contains at least one selected from the repeating unit represented by the following formula (D3), the repeating unit represented by the following formula (D4), the repeating unit represented by the following formula (D5), and the repeating unit represented by the following formula (D6), and may further contain at least one selected from the repeating unit represented by the following formula (D1) and the repeating unit represented by the following formula (D2). A chemically amplified positive resist composition. 【Chemical Formula 1】 (In the formula, R A are each independently a hydrogen atom or a methyl group. X 1 is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or *-O-X 11 -, *-C(=O)-O-X 11 —or *—C(=O)—NH—X 11 —wherein X 11 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these groups, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. X 2 is a single bond or **—X 21 —C(=O)—O—, wherein X 21 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom. X 3 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, *—O—X 31 —, *—C(=O)—O—X 31 —or *—C(=O)—NH—X 31 —. X 31 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining these groups, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. * is a bond to a carbon atom of the main chain, and ** is a bond to an oxygen atom in the formula. X 4 is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms which may contain a hetero atom. k 1 and k 2 are each independently 0 or 1, provided that when X 4 is a single bond, k 1 and k 2 are 0. R 1 ~R 18 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. Further, R 1 and R 2 may combine with each other to form a ring together with the sulfur atom to which they are attached, and R 3 and R 4 , R 6 and R 7 , or R 9 and R 10 may combine with each other to form a ring together with the sulfur atom to which they are attached. R HF is a hydrogen atom or a trifluoromethyl group. Xa - is a non-nucleophilic counter ion. ) [Chemical Formula 2] (In the formula, R B is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 21 is a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. Y 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is a bond to the carbon atom of the main chain. A 1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of -CH 2 - constituting the saturated hydrocarbylene group may be substituted with -O-. a is an integer satisfying 0 ≦ a ≦ 5 + 2c - b. b is an integer of 1 to 3. c is an integer of 0 to 2. ) [Chemical Formula 3] (In the formula, R B is the same as described above. R 22 is a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. Y 2is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is a bond with a carbon atom in the main chain. A 2 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of -CH 2 - in the saturated hydrocarbylene group may be substituted with -O-. R 23 is an acid-labile group when e is 1, and is a hydrogen atom or an acid-labile group when e is 2 or more, but at least one is an acid-labile group. d is an integer satisfying 0 ≦ d ≦ 5 + 2f - e. e is an integer of 1 to 3. f is an integer of 0 to 2. ) 【Chemical Formula 4】 (In the formula, R B is the same as described above. Y 3 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. R 24 is an acid-labile group. ) 【Chemical Formula 5】 (In the formula, each R C is independently a hydrogen atom or a methyl group. Each R D is independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 101 is a hydrogen atom, or a linear or branched hydrocarbyl group having 1 to 5 carbon atoms in which a heteroatom-containing group may be interposed between carbon-carbon bonds. R 102 is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms in which a heteroatom-containing group may be interposed between carbon-carbon bonds. R 103 is a saturated hydrocarbyl group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, and a part of -CH 2 - constituting the saturated hydrocarbyl group may be substituted with an ester bond or an ether bond. R104, R105, R107 and R108 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. R106, R109, R110 and R111 are each independently a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms or an acid-labile group. When R106, R109, R110 and R111 are a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be interposed between carbon-carbon bonds. x is an integer of 1 to 3. y is an integer satisfying 0 ≦ y ≦ 5 + 2z - x. z is 0 or 1. m is an integer of 1 to 3. Z1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is a bond to a carbon atom of the main chain. Z2 is a single bond, -O-, *-C(=O)-O-Z21-Z22- or *-C(=O)-NH-Z21-Z22-. Z21 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. Z22 is a single bond, an ester bond, an ether bond or a sulfonamide bond. * is a bond to a carbon atom of the main chain. Z3 is a (m + 1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (m + 1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. )

2. A chemically amplified positive resist composition containing a base polymer protected by an acid-labile group and becoming alkali-soluble by the action of an acid, wherein the base polymer contains an acid-generating unit, a phenol-hydroxy group-containing unit, a unit in which the phenol-hydroxy group is protected by an acid-labile group, and a unit in which the carboxy group is protected by an acid-labile group, or an acid-generating unit, a phenol-hydroxy group-containing unit and a unit in which the phenol-hydroxy group is protected by an acid-labile group, and an acid-generating unit, a phenol-hydroxy group-containing unit and a unit in which the carboxy group is protected by an acid-labile group, The acid generating unit is a repeating unit represented by the following formula (A4), the phenolic hydroxy group-containing unit is a repeating unit represented by the following formula (B1-1), the unit in which the phenolic hydroxy group is protected by an acid-labile group is a repeating unit represented by the following formula (B2-1), and the unit in which the carboxy group is protected by an acid-labile group is a repeating unit represented by the following formula (B3-1). A chemically amplified positive resist composition in which, among all the repeating units of the polymer contained in the base polymer, the repeating unit having an aromatic ring skeleton is 60 mol% or more. [Chemical Formula 6] (In the formula, R A , R B , X 4 , R 9 , R 10 , R 11 , b and k 1 are the same as those described above. Y 3A is a single bond, a phenylene group or a naphthylene group. R 25 and R 26 are each independently an acid-labile group having an aromatic hydrocarbon group having 6 to 20 carbon atoms and / or an alicyclic hydrocarbon group having 5 to 20 carbon atoms.)

3. The chemically amplified positive resist composition according to claim 2, wherein the base polymer contains a polymer containing a repeating unit represented by formula (A4), a repeating unit represented by (B1-1), a repeating unit represented by (B2-1), and a repeating unit represented by (B3-1).

4. The chemically amplified positive resist composition according to any one of claims 1 to 3, wherein the polymer contained in the base polymer further contains a repeating unit represented by any one of the following formulas (C1) to (C3). [Chemical Formula 7] (In the formula, R B is the same as those described above. g and h are each independently an integer of 0 to 4. i is an integer of 0 to 5. j is an integer of 0 to 2. R 31 and R 32 is each independently a hydroxy group, a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom. R 33 is an acetyl group, a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms, a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group or a cyano group, and may be a hydroxy group when j is 1 or 2. Y 4 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is a bond to a carbon atom of the main chain. A 3 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of -CH 2 - constituting the saturated hydrocarbylene group may be substituted with -O-. )

5. The base polymer further contains at least one selected from a repeating unit represented by the following formula (B1), a repeating unit represented by the following formula (B2), and a repeating unit represented by the following formula (B3), and does not contain a repeating unit represented by the following formulas (A1) to (A8). The chemically amplified positive resist composition according to any one of claims 1 to 4, which contains a polymer. 【Chemical Formula 8】 (In the formula, each R A is independently a hydrogen atom or a methyl group. X1 is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or *-O-X11-, *-C(=O)-O-X11- or *-C(=O)-NH-X11-, where X11 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond or a hydroxy group. X2 is a single bond or **-X21-C(=O)-O-, where X21 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a hetero atom. X3 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, *-O-X31-, *-C(=O)-O-X31- or *-C(=O)-NH-X31-. X31 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond or a hydroxy group. * is a bond to a carbon atom of the main chain, and ** is a bond to an oxygen atom in the formula. X4 is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms which may contain a hetero atom. k1 and k2 are each independently 0 or 1, provided that when X4 is a single bond, k1 and k2 are 0. R1 to R18 are each independently a halogen atom, or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. Further, R1 and R2 may combine with each other to form a ring together with the sulfur atom to which they are attached, and R3 and R4, R6 and R7, or R9 and R10 may combine with each other to form a ring together with the sulfur atom to which they are attached. RHF is a hydrogen atom or a trifluoromethyl group. Xa− is a non-nucleophilic counter ion.) [Chemical Formula 9] (In the formula, RB is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R21 is a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. Y1 is a single bond, *−C(=O)−O− or *−C(=O)−NH−. * is a bond to the carbon atom of the main chain. A1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of −CH2− constituting the saturated hydrocarbylene group may be substituted with −O−. a is an integer satisfying 0 ≦ a ≦ 5 + 2c − b. b is an integer of 1 to 3. c is an integer of 0 to 2.) [Chemical Formula 10] (In the formula, RB is the same as described above. R22 is a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. Y2 is a single bond, *−C(=O)−O− or *−C(=O)−NH−. * is a bond to the carbon atom of the main chain. A2 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of −CH2− constituting the saturated hydrocarbylene group may be substituted with −O−. R23 is an acid-labile group when e is 1, and is a hydrogen atom or an acid-labile group when e is 2 or more, but at least one is an acid-labile group. d is an integer satisfying 0 ≦ d ≦ 5 + 2f - e. e is an integer from 1 to 3. f is an integer from 0 to 2.) [Chemical Formula 11] (In the formula, R B is the same as described above. Y 3 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. R 24 is an acid-labile group.)

6. Further, at least one selected from the repeating unit represented by the following formula (D3), the repeating unit represented by the following formula (D4), the repeating unit represented by the following formula (D5), and the repeating unit represented by the following formula (D6) is included, and further the chemical amplification positive resist composition according to claim 2, which may include at least one selected from the repeating unit represented by the following formula (D1) and the repeating unit represented by the following formula (D2). [Chemical Formula 7] (In the formula, R C are each independently a hydrogen atom or a methyl group. R D are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 101 is a hydrogen atom, or a linear or branched hydrocarbyl group having 1 to 5 carbon atoms in which a heteroatom-containing group may be interposed between carbon-carbon bonds. R 102 is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms in which a heteroatom-containing group may be interposed between carbon-carbon bonds. R 103 is a saturated hydrocarbyl group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, and a part of -CH 2 - constituting the saturated hydrocarbyl group may be substituted with an ester bond or an ether bond. R 104 R 105 R 107 and R 108 is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. R 106 , R 109 , R 110 and R 111 are independently a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms or an acid-labile group, and when R 106 , R 109 , R 110 and R 111 are a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be interposed between carbon-carbon bonds. x is an integer of 1 to 3. y is an integer satisfying 0 ≦ y ≦ 5 + 2z - x. z is 0 or 1. m is an integer of 1 to 3. Z 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is a bond to the carbon atom of the main chain. Z 2 is a single bond, -O-, *-C(=O)-O-Z 21 -Z 22 - or *-C(=O)-NH-Z 21 -Z 22 -. Z 21 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. Z 22 is a single bond, an ester bond, an ether bond or a sulfonamide bond. * is a bond to the carbon atom of the main chain. Z 3 is a (m + 1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (m + 1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. )

7. Furthermore, the chemically amplified positive resist composition according to any one of claims 1 to 6, further comprising an organic solvent.

8. Furthermore, the chemically amplified positive resist composition according to any one of claims 1 to 7, further comprising a photoacid generator.

9. The chemically amplified positive resist composition according to claim 8, wherein the acid strength (pKa) of the anion of the photoacid generator is -2.0 or more.

10. The chemically amplified positive resist composition according to any one of claims 1 to 9, wherein the dissolution rate of the overexposed portion of the resist film obtained from the chemically amplified positive resist composition is 50 nm / sec or more.

11. A resist pattern forming method comprising a step of forming a resist film on a substrate using the chemically amplified positive resist composition according to any one of claims 1 to 10, a step of irradiating the resist film with a high-energy ray to form a pattern, and a step of developing the resist film irradiated with the pattern using an alkaline developer.

12. The resist pattern forming method according to claim 11, wherein the high-energy ray is an extreme ultraviolet ray or an electron beam.

13. The resist pattern forming method according to claim 11 or 12, wherein the outermost surface of the substrate is made of a material containing at least one selected from chromium, silicon, tantalum, molybdenum, cobalt, nickel, tungsten, and tin.

14. The resist pattern forming method according to any one of claims 11 to 13, wherein the substrate is a photomask blank.

15. A photomask blank coated with the chemically amplified positive resist composition according to any one of claims 1 to 10.

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