Chemical amplification positive resist composition and resist pattern forming method

Abstract

The present invention relates to a chemically amplified positive resist composition and a resist pattern forming method. The present invention provides a chemically amplified positive resist composition which is capable of forming a resist film having an extremely high resolution, a small LER, excellent rectangularity, and a pattern whose development load is inhibited. A chemically amplified positive resist composition comprising a base polymer containing a polymer including a unit containing a phenolic hydroxyl group, a unit in which a phenolic hydroxyl group is protected by an acid-labile group, and a unit in which a carboxyl group is protected by an acid-labile group, or a polymer including a unit containing a phenolic hydroxyl group and a unit in which a phenolic hydroxyl group is protected by an acid-labile group and a polymer including a unit containing a phenolic hydroxyl group and a unit in which a carboxyl group is protected by an acid-labile group, in which, of all repeating units of the polymers contained in the base polymer, repeating units having an aromatic ring skeleton are 65 mol% or more.

Description

TECHNICAL FIELD

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

[0002] In recent years, with the high integration of integrated circuits, more fine patterns are required to be formed, and for pattern processing of 0.2 μm or less, a chemical amplification resist composition using acid as a catalyst is mainly used. Also, at this time, a high-energy ray such as ultraviolet ray, far ultraviolet ray, extreme ultraviolet ray (EUV), electron beam (EB) or the like is used as an exposure source, but particularly, EB lithography as a super-fine processing technique is indispensable as a processing method for a blank photomask for manufacturing a photomask for semiconductor manufacturing.

[0003] Generally, in EB lithography, drawing by EB is performed without using a mask. In the case of a positive resist, a method of sequentially irradiating a fine area of EB to a portion other than a region of a resist film to be retained is adopted, and in the case of a negative resist, a method of sequentially irradiating a fine area of EB to a region of a resist film to be retained is adopted. That is, scanning is performed on all regions of a fine division of a processing surface, and thus, time is taken compared with batch exposure using a photomask, and a resist film with high sensitivity is required in order not to decrease productivity. Particularly, in processing of a blank photomask for an important use, a surface material such as a chromium compound film of chromium oxide or the like, which easily influences the pattern shape of a chemical amplification resist film, is sometimes present on a film formed on a photomask substrate, and in order to maintain high resolution and the shape after etching, it is also one of important properties to maintain the pattern profile of a resist film as a rectangle regardless of the kind of a substrate. Also, line edge roughness (LER) is also one of properties that are valued.

[0004] For sensitivity, control of the pattern profile, various improvements have been made using the selection, combination, and processing conditions of the material used for the resist composition. As one of such improvements, there is inhibition of acid diffusion, which has a significant influence on the resolution of a resist film. In processing of a photomask, the shape of a resist pattern to be obtained varies depending on the time from exposure to heating. One of the reasons for the time-dependent variation of the shape of a resist pattern is diffusion of acid generated by exposure. This problem of acid diffusion is not limited to processing of a photomask, but also has a significant influence on sensitivity and resolution in general resist compositions, and thus, many studies have been made.

[0005] Patent Document 1 and Patent Document 2 describe examples in which acid diffusion is inhibited and LER is reduced by making the acid generated from an acid generator large in volume. However, such an acid generator has not yet sufficiently inhibited acid diffusion, and it is desired to develop an acid generator with less diffusion.

[0006] Further, Patent Document 3 describes an example in which a repeating unit having a sulfonium structure that generates a sulfonic acid upon exposure is introduced into a polymer used for a resist composition, in order to control acid diffusion. This method of suppressing acid diffusion by introducing a repeating unit that generates an acid upon exposure into a base polymer is effective as a method of obtaining a pattern with small LER. However, a base polymer containing such a repeating unit that generates an acid upon exposure has cases in which solubility in organic solvents is problematic, depending on the structure of the unit and the rate of introduction.

[0007] There are a large number of polymers having an aromatic skeleton with an acidic side chain, such as polyhydroxystyrene, that are useful as base polymers for KrF photoresist compositions, but cannot be used as base polymers for ArF photoresist compositions because of large absorption of light with a wavelength of around 200 nm. However, as a powerful technology for forming patterns that are smaller than the processing limit with ArF excimer laser, i.e., EB photoresist compositions, EUV photoresist compositions, in terms of obtaining high etching resistance, they are important materials.

[0008] As a base polymer for positive EB photoresist compositions and EUV photoresist compositions, a material is mainly used that, using an acid generated by irradiation of high-energy rays on a photoacid generator as a catalyst, deprotects an acid-labile group that covers an acidic functional group of a phenol side chain possessed by the base polymer, and thus becomes soluble in an alkali developer. Further, the aforementioned acid-labile group mainly uses a tertiary alkyl group, a tert-butoxycarbonyl group, an acetal group, and the like. Here, if an acid-labile group with a small activation energy required for deprotection, such as an acetal group, is used, there is an advantage of obtaining a high-sensitivity resist film, but when the diffusion of the generated acid is not sufficiently suppressed, deprotection reactions occur even in unexposed portions in the resist film, causing problems of resolution and LER degradation.

[0009] On the other hand, in the development step of a photomask, it is known that a so-called development loading phenomenon in which the completed size of a pattern on a dense region and a sparse region of the photomask differs occurs. That is, due to the development loading, a non-uniform distribution of the completed size of the pattern occurs depending on the distribution of the surrounding pattern. As the causes, the difference in the elimination reaction at the time of acid generation due to the energy difference of the EB, and the difference in the dissolution rate of the sparse and dense pattern drawing portion to the alkali developer can be listed. As one of the improvement methods, Patent Literature 4 describes a method in which the EB is irradiated while adjusting the incident dose in the EB drawing device, and the pattern drawing is performed on the photomask in order to correct the development loading. However, the conventional correction method does not sufficiently correct the development loading phenomenon. Therefore, the correction accuracy of the conventional correction method is poor. In order to solve this, the drawing method at the time of drawing a resist film described in Patent Literature 5 and Patent Literature 6, and the method of improving the development method after patterning have been developed, but in the advanced generation, the uniform distribution of the sparse and dense fine patterns has not been satisfactory, and it is desired to improve the resist composition.

[0010] Prior Art Documents

[0011] Patent Literature

[0012] [Patent Literature 1] Japanese Patent Application Laid-Open No. 2009-053518

[0013] [Patent Literature 2] Japanese Patent Application Laid-Open No. 2010-100604

[0014] [Patent Literature 3] Japanese Patent Application Laid-Open No. 2011-22564

[0015] [Patent Literature 4] Japanese Patent Application Laid-Open No. 2007-150243

[0016] [Patent Literature 5] Japanese Patent No. 5443548

[0017] [Patent Literature 6] Japanese Patent No. 6281244 SUMMARY

[0018] [Problems to be Solved by the Invention]

[0019] The present application has been made in view of the foregoing circumstances, and an object thereof is to provide a chemically amplified positive resist composition which can form a resist film having an extremely high resolution, a small LER, and excellent rectangularity, and can form a pattern in which the influence of development loading is suppressed, and a resist pattern forming method using the same.

[0020] [Means for Solving the Problems]

[0021] As a result of intensive studies made by the present inventors and others in order to achieve the foregoing object, it has been found that by introducing a base polymer having a specific structure into a resist composition, a pattern exhibiting good resolution, pattern shape and LER, and the influence of development load being suppressed, can be obtained, thus completing the present application.

[0022] That is, the present application provides the following positive chemically amplified resist composition and resist pattern forming method.

[0023] 1. A positive chemically amplified resist composition comprising a base polymer protected by an acid-labile group, which becomes alkali-soluble by the action of an acid,

[0024] the base polymer includes a polymer containing a unit containing a phenolic hydroxyl group, a unit in which a phenolic hydroxyl group is protected by an acid-labile group, and a unit in which a carboxyl group is protected by an acid-labile group, or

[0025] a polymer containing a unit containing a phenolic hydroxyl group and a unit in which a phenolic hydroxyl group is protected by an acid-labile group, and a polymer containing a unit containing a phenolic hydroxyl group and a unit in which a carboxyl group is protected by an acid-labile group,

[0026] the unit containing a phenolic hydroxyl group is a repeating unit represented by the following formula (Al), the unit in which a phenolic hydroxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (A2), and the unit in which a carboxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (A3),

[0027] of all the repeating units of the polymer contained in the base polymer, the repeating unit having an aromatic ring skeleton is 65 mol% or more,

[0028] [Chemical Formula 1]

[0029]

[0030] in the formula, a is an integer satisfying 0 ≤ a ≤ 5 + 2c - b, b is an integer of 1 to 3, and c is an integer of 0 to 2,

[0031] R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0032] X 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * is an atomic bond between the carbon atom of the main chain,

[0033] A 1 is a single bond or a saturated hydrocarbylene group having a carbon number of 1 to 10, and a part of -CH2- constituting the saturated hydrocarbylene group can also be replaced by -O-,

[0034] R 1a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which can be substituted with a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which can be substituted with a halogen atom, or a saturated hydrocarbon oxy group having 1 to 6 carbon atoms which can be substituted with a halogen atom,

[0035] [Chemical Formula 2]

[0036]

[0037] in the formula, R A the same as mentioned above,

[0038] d is an integer satisfying 0 ≤ d ≤ 5 + 2f - e, e is an integer of 1 to 3, and f is an integer of 0 to 2,

[0039] X 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * is an atomic bond between the carbon atom of the main chain,

[0040] A 2 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, a part of -CH2- constituting the saturated hydrocarbylene group can also be substituted with -O-,

[0041] R 2 a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which can be substituted with a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which can be substituted with a halogen atom, or a saturated hydrocarbon oxy group having 1 to 6 carbon atoms which can be substituted with a halogen atom,

[0042] R 3 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, at least one of which is an acid-labile group,

[0043] [Chemical Formula 3]

[0044]

[0045] in the formula, R A the same as mentioned above,

[0046] X 3 is a single bond, phenylene, naphthylene or *-C(=O)-O-X 3A -, X 3A is a saturated hydrocarbylene group having 1 to 20 carbon atoms which can also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring, or phenylene or naphthylene, * is an atomic bond between the carbon atom of the main chain,

[0047] R 4 is an acid-labile group.

[0048] 2. The positive chemically amplified resist composition of 1, wherein the phenolic hydroxyl group-containing unit is a repeating unit represented by the following formula (Al-1),

[0049] [Chem. 4]

[0050]

[0051] wherein R A and b are as previously described.

[0052] 3. The chemically amplified positive resist composition of 1. or 2., wherein the unit in which the phenolic hydroxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (A2-1),

[0053] [Chem. 5]

[0054]

[0055] wherein R A and b are as previously described, R 5 is an acid-labile group having an aromatic hydrocarbon group having a carbon number of 6 to 20 and / or an alicyclic hydrocarbon group having a carbon number of 5 to 20.

[0056] 4. The chemically amplified positive resist composition of any one of 1. to 3., wherein the unit in which the carboxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (A3-1),

[0057] [Chem. 6]

[0058]

[0059] wherein R A and X 3 are as previously described, R 6 is an acid-labile group having an aromatic hydrocarbon group having a carbon number of 6 to 20 and / or an alicyclic hydrocarbon group having a carbon number of 5 to 20.

[0060] 5. The chemically amplified positive resist composition of any one of 1. to 3., wherein the unit in which the carboxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (A3-2),

[0061] [Chem. 7]

[0062]

[0063] wherein R A and X 3 are as previously described,

[0064] R B and R C each independently is a hydrocarbon group having a carbon number of 1 to 10 which can also contain a hetero atom, R B and R C may also be bonded to each other and form a ring together with the carbon atom to which they are bonded,

[0065] R 7 each independently is a fluorine atom, a fluorinated alkyl group having a carbon number of 1 to 5, or a fluorinated alkoxy group having a carbon number of 1 to 5,

[0066] R 8 each independently is a hydrocarbon group having a carbon number of 1 to 10 which can also contain a hetero atom,

[0067] n1 is 1 or 2, n2 is an integer of 0 to 5, and n3 is an integer of 0 to 2.

[0068] 6. The chemically amplified positive resist composition of 5, wherein the repeating unit represented by formula (A3-2) is represented by formula (A3-3),

[0069] [Chemical Formula 8]

[0070]

[0071] wherein R A , R B , R C , X 3 , R 7 , R 8 , n1 and n2 are as described above.

[0072] 7. The chemically amplified positive resist composition of 5 or 6, wherein R 7 is a fluorine atom, a trifluoromethyl group, or a trifluoromethoxy group.

[0073] 8. The chemically amplified positive resist composition of any one of 1 to 7, wherein the polymer contained in the base polymer further contains a repeating unit represented by any one of the following formulas (B1) to (B3),

[0074] [Chemical Formula 9]

[0075]

[0076] wherein R A are as described above,

[0077] each of g and h independently is an integer of 0 to 4, i is an integer of 0 to 5, and j is an integer of 0 to 2,

[0078] R 11 and R 12 each independently is a hydroxyl group, a halogen atom, a saturated hydrocarbon carbonyloxy group having a carbon number of 2 to 8 which can also be substituted with a halogen atom, a saturated hydrocarbon group having a carbon number of 1 to 8 which can also be substituted with a halogen atom, or a saturated hydrocarbon oxy group having a carbon number of 1 to 8 which can also be substituted with a halogen atom,

[0079] R 13an acetyl group, a saturated hydrocarbon group having 1 to 20 carbons, a saturated hydrocarbon oxy group having 1 to 20 carbons, a saturated hydrocarbon carbonyloxy group having 2 to 20 carbons, a saturated hydrocarbon oxyhydrocarbon group having 2 to 20 carbons, a saturated hydrocarbon thiohydrocarbon group having 2 to 20 carbons, a halogen atom, a nitro group or a cyano group, and when j is 1 or 2, a hydroxyl group,

[0080] X 4 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * is an atomic bond between the carbon atom of the main chain,

[0081] A 3 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbons, and a part of -CH2- constituting the saturated hydrocarbylene group can also be replaced with -O-.

[0082] 9. The chemical amplification positive resist composition of 8, wherein the total of the repeating unit represented by formula (Al) and the repeating unit represented by any one of formulae (Bl) to (B3) is 50 mol% or more of the entire repeating units of the polymer contained in the base polymer.

[0083] 10. The chemical amplification positive resist composition according to any one of claims 1 to 9, further comprising a polymer containing a fluorine atom, the polymer containing the fluorine atom containing at least one selected from the group consisting of a repeating unit represented by formula (Cl), a repeating unit represented by formula (C2), a repeating unit represented by formula (C3) and a repeating unit represented by formula (C4), and can further contain at least one selected from the group consisting of a repeating unit represented by formula (C5) and a repeating unit represented by formula (C6),

[0084] [Chemical Formula 10]

[0085]

[0086] in the formula, R D each independently is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group,

[0087] R E each independently is a hydrogen atom or a methyl group,

[0088] R 101 , R 102 , R 104 and R 105 each independently is a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbons,

[0089] R 103 , R 106 , R 107 and R 108 each independently is a hydrogen atom, a hydrocarbon group having 1 to 15 carbons, a fluorinated hydrocarbon group having 1 to 15 carbons or an acid labile group, R 103 , R106 R 107 and R 108 when R

[0090] R 109 is a linear or branched hydrocarbon group having 1 to 5 carbons in which at least one hydrogen atom is substituted with a fluorine atom,

[0091] R 110 is a linear or branched hydrocarbon group having 1 to 5 carbons in which at least one hydrogen atom is substituted with a fluorine atom,

[0092] R 111 is a saturated hydrocarbon group having 1 to 20 carbons in which at least one hydrogen atom is substituted with a fluorine atom, and a part of -CH2- constituting the saturated hydrocarbon group can be substituted with an ester bond or an ether bond,

[0093] x is an integer of 1 to 3, y is an integer satisfying 0 ≤ y ≤ 5 + 2z - x, z is 0 or 1, and m is an integer of 1 to 3,

[0094] Z 1 is a (m+1)-valent hydrocarbon group having 1 to 20 carbons or a (m+1)-valent fluorinated hydrocarbon group having 1 to 20 carbons,

[0095] Z 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * is an atomic bond between the carbon atom of the main chain and the carbon atom of Z

[0096] Z 3 is a single bond, -O-, *-C(=O)-O-Z 31 -Z 32 or *-C(=O)-NH-Z 31 -Z 32 , Z 31 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbons, Z 32 is a single bond, an ester bond, an ether bond or a sulfonamide bond, and * is an atomic bond between the carbon atom of the main chain and the carbon atom of Z

[0097] 11. The chemically amplified positive resist composition according to any one of 1. to 10., further comprising an organic solvent.

[0098] 12. The chemically amplified positive resist composition according to any one of 1. to 10., further comprising a photo-acid generator.

[0099] 13. The chemically amplified positive resist composition according to 12., wherein the acid strength (pKa) of the anion of the photo-acid generator is -2.0 or more.

[0100] 14. The chemically amplified positive resist composition according to any one of 1. to 13., wherein a dissolution rate of an overexposed portion of a resist film obtained from the chemically amplified positive resist composition is 50 nm / sec or more.

[0101] 15. A resist pattern forming method comprising the steps of:

[0102] forming a resist film on a substrate using the chemically amplified positive resist composition according to any one of 1. to 14.;

[0103] irradiating a pattern to the resist film using a high-energy ray;

[0104] and developing the resist film of the irradiated pattern using an alkali developer.

[0105] 16. The resist pattern forming method according to 15., wherein the high-energy ray is an extreme ultraviolet ray or an electron beam.

[0106] 17. The resist pattern forming method according to 15. or 16., wherein a topmost surface of the substrate is composed of a material containing at least one selected from the group consisting of chromium, silicon, tantalum, molybdenum, cobalt, nickel, tungsten and tin.

[0107] 18. The resist pattern forming method according to any one of 15. to 17., wherein the substrate is a blank photomask.

[0108] 19. A blank photomask coated with the chemically amplified positive resist composition according to any one of 1. to 14.

[0109] [Effects of the Invention]

[0110] The chemically amplified positive resist composition of the present application can form a pattern with high resolution, small LER, good shape after exposure, excellent rectangularity, and suppressed influence of development load, and is suitable as a resist composition for forming a resist film for processing using a high-energy ray such as ultraviolet, far ultraviolet, EB, EUV, X-ray, gamma ray, synchrotron radiation, and the like for a semiconductor, a blank photomask, and the like. Also, the pattern forming method using the chemically amplified positive resist composition of the present application can form a pattern with high resolution, etching resistance, small LER, and suppressed influence of development load, and is suitable for use in microprocessing technology, particularly EUV lithography, EB lithography. DETAILED DESCRIPTION

[0111] Hereinafter, the present application will be described in detail. Also, in the following description, depending on the structure represented by the chemical formula, there can be an asymmetric carbon and there can be a mirror image isomer, a non-mirror image isomer, and in this case, one general formula is represented to represent these isomers. These isomers can be used alone or in the form of a mixture.

[0112] [Chemical amplification positive resist composition]

[0113] The chemical amplification positive resist composition of the present application contains a base polymer protected by an acid-labile group, which becomes alkali-soluble by action of an acid.

[0114] The aforementioned base polymer includes a polymer containing a unit containing a phenolic hydroxyl group, a unit in which a phenolic hydroxyl group is protected by an acid-labile group, and a unit in which a carboxyl group is protected by an acid-labile group, or a polymer containing a unit containing a phenolic hydroxyl group and a unit in which a phenolic hydroxyl group is protected by an acid-labile group, and a polymer containing a unit containing a phenolic hydroxyl group and a unit in which a carboxyl group is protected by an acid-labile group.

[0115] The aforementioned unit containing a phenolic hydroxyl group is a repeating unit represented by the following formula (Al) (hereinafter also referred to as repeating unit Al).

[0116] [Chemical 11]

[0117]

[0118] In formula (Al), 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.

[0119] In formula (Al), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0120] In formula (Al), X 1 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * is an atomic bond between the carbon atom of the main chain.

[0121] In formula (Al), A 1 is a single bond or a saturated hydrocarbylene group having a carbon number of 1 to 10, and a part of -CH2- constituting the saturated hydrocarbylene group can also be replaced by -O-. The aforementioned saturated hydrocarbylene group can be linear, branched, or cyclic, and specific examples thereof can include alkandiyl groups having a carbon number of 1 to 10 such as methylene, ethane-1, 2-diyl, propane-1, 3-diyl, butane-1, 4-diyl, pentane-1, 5-diyl, hexane-1, 6-diyl, structural isomers thereof, and the like; cyclic saturated hydrocarbylene groups having a carbon number of 3 to 10 such as cyclopropane-diyl, cyclobutane-diyl, cyclopentane-diyl, cyclohexane-diyl, and the like; and groups obtained by combining them.

[0122] In formula (Al), R 1a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which can be substituted with a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which can be substituted with a halogen atom, or a saturated hydrocarbon oxy group having 1 to 6 carbon atoms which can be substituted with a halogen atom. The aforementioned saturated hydrocarbon group, and the saturated hydrocarbon group portion of the saturated hydrocarbon carbonyloxy group and the saturated hydrocarbon oxy group can be linear, branched, or cyclic, and specific examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, butyl, pentyl, hexyl, and the like; cyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like; and groups obtained by combining these. If the number of carbons is equal to or less than the upper limit, solubility in an alkali developer is good. If a is 2 or more, each R 1 These can be the same or different.

[0123] X 1 and A 1 When both of X and A are single bonds, ideal examples of the repeating unit A1 include units derived from 3-hydroxystyrene, 4-hydroxystyrene, 5-hydroxy-2-vinylnaphthalene, 6-hydroxy-2-vinylnaphthalene, and the like. Of these, more preferable are repeating units represented by the following formula (A1-1) and the like.

[0124] [Chemical Formula 12]

[0125]

[0126] In the formula, R A and b are the same as described above.

[0127] X 1 When X is other than a single bond, ideal examples of the repeating unit A1 include the following, but are not limited thereto. Also, in the following formula, R A is the same as described above.

[0128] [Chemical Formula 13]

[0129]

[0130] [Chemical Formula 14]

[0131]

[0132] The repeating unit A1 is preferably introduced in a range of 10 to 95 mol% of all repeating units of the polymer contained in the base polymer, more preferably in a range of 30 to 85 mol%. However, when at least one or more of the repeating unit represented by formula (B1) and the repeating unit represented by formula (B2) which impart high etching resistance using the polymer described later are contained and this unit has a phenolic hydroxyl group as a substituent, it is also preferable to add the ratio thereof to be within the aforementioned range. The repeating unit A1 can be used alone or in combination with two or more.

[0133] The unit in which the aforementioned phenolic hydroxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (A2) (hereinafter also referred to as repeating unit A2).

[0134] [Chemical Formula 15]

[0135]

[0136] In formula (A2), R A The same as described above. 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.

[0137] In formula (A2), X 2 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * is an atomic bond between the carbon atom of the main chain.

[0138] In formula (A2), 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 can also be replaced by -O-. The aforementioned saturated hydrocarbylene group can be linear, branched, or cyclic, and specific examples thereof can be exemplified by A 1 The example exemplified in the description of the aforementioned R

[0139] In formula (A2), R 2 is a halogen atom, a saturated hydrocarbyloxy group having 2 to 8 carbon atoms which can also be substituted by a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which can also be substituted by a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which can also be substituted by a halogen atom. The aforementioned saturated hydrocarbyl group, and the saturated hydrocarbyl part of the saturated hydrocarbyloxy group and the saturated hydrocarbyloxy group can be linear, branched, or cyclic, and specific examples thereof can be exemplified by R 1 The example exemplified in the description of the aforementioned R 2 may be the same as or different from each other.

[0140] In formula (A2), R 3 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 of them is an acid-labile group.

[0141] The aforementioned unit in which the aforementioned carboxyl group is protected by an acid-labile group is a repeating unit represented by the following formula (A3) (hereinafter also referred to as repeating unit A3).

[0142] [Chemical Formula 16]

[0143]

[0144] In formula (A3), R A The same as described above. X3 is a single bond, phenylene, naphthylene, or *-C(=O)-O-X 3A , X 3A is a saturated hydrocarbylene group having a carbon number of 1 to 20 which can also contain a hydroxyl group, an ether bond, an ester bond, or a lactone ring, or a phenylene or naphthylene group. * is an atomic bond between the carbon atom of the main chain and R 4 is an acid-labile group.

[0145] In the repeating unit A2, the hydrogen atom of the phenolic hydroxyl group is substituted with an acid-labile group, and in particular, the hydrogen atom of the hydroxyl group of a hydroxystyrene or a hydroxyphenyl (meth)acrylate is preferably substituted with an acid-labile group. Ideal examples of the repeating unit A2 can be listed below but are not limited to these. Also, in the following formula, R A and R 3 are the same as described above.

[0146] [Chemical Formula 17]

[0147]

[0148] Also, the repeating unit A3 is a repeating unit in which the hydrogen atom of the carboxyl group is substituted with an acid-labile group, and in particular, a repeating unit in which the hydrogen atom of the carboxyl group of a (meth)acrylate is preferably substituted with an acid-labile group. Ideal examples of the repeating unit A3 can be listed below but are not limited to these. Also, in the following formula, R A and R 4 are the same as described above.

[0149] [Chemical Formula 18]

[0150]

[0151] [Chemical Formula 19]

[0152]

[0153] The acid-labile groups represented by R 3 and R 4 are not particularly limited as long as they are acid-labile groups that provide an acidic group by acid dissociation, which are used in various chemical amplification resist compositions known in the art, and all of them can be used. For example, the aforementioned acid-labile groups can be listed as the acid-labile groups described in paragraphs

[0030] to

[0082] of Japanese Patent Application Publication No. 2014-219657.

[0154] The aforementioned acid-labile groups are preferably acid-labile groups represented by the following formulas (AL-1) to (AL-19).

[0155] [Chemical Formula 20]

[0156]

[0157] In the formula, the dotted line is a bond of an atom.

[0158] In the formulae (AL-1) to (AL-19), R L1 each independently is a saturated hydrocarbon group or an aromatic group having 6 to 20 carbons. R L2 and R L4 each independently is a hydrogen atom or a saturated hydrocarbon group having 1 to 20 carbons. R L3 is an aromatic group having 6 to 20 carbons. The aforementioned saturated hydrocarbon group can be linear, branched, or cyclic. Also, the aforementioned aromatic group is preferably a phenyl group or the like. R F is a fluorine atom or a trifluoromethyl group. n is an integer of 1 to 5. Especially ideal structures are (AL-1), (AL-2), and (AL-19), which can achieve resolution improvement by suppressing swelling at the time of development with an alkali.

[0159] If a tertiary hydrocarbon group is selected as the aforementioned acid-labile group, a pattern with a small LER can be provided even when the film thickness of the resist film is, for example, 10 to 100 nm and a fine pattern with, for example, a line width of 45 nm or less is formed, and thus is ideal. For the aforementioned tertiary hydrocarbon group, in order to obtain a monomer for polymerization by distillation, a tertiary hydrocarbon group having 4 to 18 carbons is preferable. Also, the group bonded to the tertiary carbon atom of the aforementioned tertiary hydrocarbon group can be a saturated hydrocarbon group having 1 to 20 carbons, which can also include an ether bond, a carbonyl group, and an oxygen atom-containing functional group, and the groups bonded to the tertiary carbon atom of the aforementioned tertiary hydrocarbon group can also be bonded to each other to form a ring.

[0160] Specific examples of the group bonded to the tertiary carbon atom of the aforementioned tertiary hydrocarbon group can include a methyl group, an ethyl group, a propyl group, an adamantyl group, a norbornyl group, a tetrahydrofuran-2-yl group, a 7-oxanorbornan-2-yl group, a cyclopentyl group, a 2-tetrahydrofuryl group, a tricyclo[5.2.1.02,6]decyl group, a tetracyclo[4.4.0.12,7.3 2,6 .1 2,5 .1 7,10 ]dodecyl group, and a 3-oxo-1-cyclohexyl group.

[0161] The aforementioned tertiary hydrocarbon group can 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, a 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, a 1-isopropylcyclohexyl group, a 1-cyclopentylcyclohexyl group, a 1-cyclohexylcyclohexyl group, a 2-methyl-2-norbornyl group, a 2-ethyl-2-norbornyl group, a 8-methyl-8-tricyclo[5.2.1.02,6]decyl group, a 8-ethyl-8-tricyclo[5.2.1.02,6]decyl group, a 8-isopropyl-8-tricyclo[5.2.1.02,6]decyl group, a 8-cyclopentyl-8-tricyclo[5.2.1.02,6]decyl group, a 8-cyclohexyl-8-tricyclo[5.2.1.02,6]decyl group, a 8-(2-tetrahydrofuryl)-8-tricyclo[5.2.1.02,6]decyl group, a 8-(7-oxanorbornan-2-yl)-8-tricyclo[5.2.1.02,6]decyl group, a 8-methyl-8-tetracyclo[4.4.0.12,7.32,6 ]decyl, 8-ethyl-8-tricyclo[5.2.1.02'6]decyl, 2,6 ]decyl, 3-ethyl-3-tetracyclo[4.4.0.12'5]decyl, 2,5 .1 7,10 ]dodecyl, 3-ethyl-3-tetracyclo[4.4.0.12'5]decyl, 2,5 .1 7,10 ]dodecyl, 3-ethyl-3-tetracyclo[4.4.0.12'5]decyl, 2,5 .1 7,10 ]dodecyl, 3-ethyl-3-tetracyclo[4.4.0.12'5]decyl,

[0162] Further, the acetal group represented by the following formula (AL-20) is often used as the acid-labile group, and is a useful option as an acid-labile group that stably provides a pattern that is more rectangular than the interface between the pattern and the substrate.

[0163] [Chemical Formula 21]

[0164]

[0165] In formula (AL-20), R L5 is a hydrogen atom or a saturated hydrocarbon group having 1 to 10 carbons. R L6 is a saturated hydrocarbon group having 1 to 30 carbons.

[0166] R L5 may be appropriately selected depending on the design of the sensitivity of the decomposable group to acid. For example, if the design is to decompose with a strong acid in order to ensure relatively high stability, a hydrogen atom can be selected, and if the design is to use higher reactivity and to be highly sensitive to pH changes, a straight-chain alkyl group can be selected. Although this also depends on the combination of the acid generator and the basic compound incorporated in the resist composition, when R L6 is substituted at the end with a relatively large alkyl group and is designed to have a large change in solubility due to decomposition, R L5 is preferably a secondary carbon atom bonded to the acetal carbon. Examples of R L5 bonded to the acetal carbon with a secondary carbon atom include isopropyl, sec-butyl, cyclopentyl, and cyclohexyl.

[0167] Among the aforementioned acetal groups, R L6 is preferably a polycyclic alkyl group having 7 to 30 carbons in order to achieve higher resolution. Further, R L6When the polyalkylene oxide group is a polycyclic alkyl group, it is preferable to form a bond to a secondary carbon atom constituting the polycyclic ring structure and the acetal oxygen. When a bond is formed to a secondary carbon atom of the ring structure, the polymer becomes a more stable compound compared to the case where a bond is formed to a tertiary carbon atom, the storage stability of the resist composition becomes good, and the resolution is not deteriorated. Also, compared to the case where a bond is formed to a primary carbon atom of a linear alkyl group having 1 or more carbon atoms, the glass transition temperature (Tg) of the polymer becomes good, and the resist pattern after development does not undergo shape deterioration due to baking. L6 When a bond is formed to a primary carbon atom of a linear alkyl group having 1 or more carbon atoms, the glass transition temperature (Tg) of the polymer becomes good, and the resist pattern after development does not undergo shape deterioration due to baking.

[0168] Desirable examples of the group represented by formula (AL-20) can be listed below, but are not limited to these. Also, in the following formulae, R L5 The same as described above.

[0169] [Chemical Formula 22]

[0170]

[0171] The repeating unit A2 is preferably a repeating unit represented by the following formula (A2-1), and the repeating unit A3 is preferably a repeating unit represented by the following formula (A3-1).

[0172] [Chemical Formula 23]

[0173]

[0174] In the formula, R A and X 3 The same as described above. R 5 and R 6 Each independently is an acid-labile group which is an aromatic hydrocarbon group having 6 to 20 carbon atoms and / or an alicyclic hydrocarbon group having 5 to 20 carbon atoms.

[0175] The repeating unit A3 is also preferably a repeating unit represented by the following formula (A3-2).

[0176] [Chemical Formula 24]

[0177]

[0178] In formula (A3-2), R A and X 3 The same as described above. R B and R C Each independently is a hydrocarbon group having 1 to 10 carbon atoms which can also contain a hetero atom. The aforementioned hydrocarbon group can be either saturated or unsaturated, and can be either linear, branched, or cyclic. Specific examples thereof can be listed as follows: alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, 2-ethylhexyl, n-octyl, and the like; alicyclic saturated hydrocarbon groups having 3 to 10 carbon atoms such as cyclopentyl, cyclohexyl, norbornyl, tricyclodecyl, adamantyl, and the like.

[0179] R B R C may be bonded to each other and form a ring together with the carbon atom to which they are bonded. Examples of the aforementioned ring include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, and the like. Among these, a cyclopentane ring and a cyclohexane ring are preferable.

[0180] R 7 each independently is a fluorine atom, a fluorinated alkyl group having a carbon number of 1 to 5, or a fluorinated alkoxy group having a carbon number of 1 to 5. Examples of the aforementioned fluorinated alkyl group include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a pentafluoroethyl group, a pentafluoropropyl group, a 1,1,1,3,3,3-hexafluoro-2-propyl group, a nonafluorobutyl group, and the like. Examples of the aforementioned fluorinated alkoxy group include a fluoromethoxy group, a difluoromethoxy group, a trifluoromethoxy group, a 2,2,2-trifluoroethoxy group, a pentafluoroethoxy group, a pentafluoropropoxy group, a 1,1,1,3,3,3-hexafluoro-2-propoxy group, a nonafluorobutoxy group, and the like. Among these, a fluorine atom, a fluorinated alkyl group having a carbon number of 1 to 5, or a fluorinated alkoxy group having a carbon number of 1 to 5 is preferable, and a fluorine atom is more preferable. 7 A fluorine atom or a fluorinated alkyl group having a carbon number of 1 to 5 is preferable, and a fluorine atom is more preferable.

[0181] R 8 each independently is a hydrocarbon group having a carbon number of 1 to 10, which can also contain a hetero atom. The aforementioned hydrocarbon group can be either saturated or unsaturated, and can be either linear, branched, or cyclic. Specific examples thereof include the same groups as those exemplified for R B and R C represent the same groups.

[0182] In formula (A3-2), n1 is 1 or 2. n2 is an integer of 0 to 5, but is preferably 0 or 1. n3 is an integer of 0 to 2. When n3 is 0, it is a benzene ring, when n3 is 1, it is a naphthalene ring, and when n3 is 2, it is an anthracene ring, but from the viewpoint of solubility in a solvent, a benzene ring in which n3 is 0 is preferable.

[0183] The repeating unit represented by formula (A3-2) is preferably a repeating unit represented by the following formula (A3-3).

[0184] [Chemical Formula 25]

[0185]

[0186] In the formula, R A , R B , R C , X 3 , R 7 , R 8 , n1 and n2 are the same as described above.

[0187] The repeating unit represented by formula (A3-2) can be exemplified as follows but is not limited thereto. In the following formula, R AAs described above.

[0188] [Chem. 26]

[0189]

[0190] [Chem. 27]

[0191]

[0192] [Chem. 28]

[0193]

[0194] [Chem. 29]

[0195]

[0196] [Chem. 30]

[0197]

[0198] [Chem. 31]

[0199]

[0200] [Chem. 32]

[0201]

[0202] [Chem. 33]

[0203]

[0204] [Chem. 34]

[0205]

[0206] [Chem. 35]

[0207]

[0208] [Chem. 36]

[0209]

[0210] [Chem. 37]

[0211]

[0212] [Chem. 38]

[0213]

[0214] [Chem. 39]

[0215]

[0216] [Chemical Formula 40]

[0217]

[0218] [Chemical Formula 41]

[0219]

[0220] [Chemical Formula 42]

[0221]

[0222] [Chemical Formula 43]

[0223]

[0224] [Chemical Formula 44]

[0225]

[0226] [Chemical Formula 45]

[0227]

[0228] [Chemical Formula 46]

[0229]

[0230] [Chemical Formula 47]

[0231]

[0232] [Chemical Formula 48]

[0233]

[0234] [Chemical Formula 49]

[0235]

[0236] [Chemical Formula 50]

[0237]

[0238] [Chemical Formula 51]

[0239]

[0240] [Chemical Formula 52]

[0241]

[0242] [Chemical Formula 53]

[0243]

[0244] [Chemical Formula 54]

[0245]

[0246] [Chem. 55]

[0247]

[0248] [Chem. 56]

[0249]

[0250] [Chem. 57]

[0251]

[0252] The acid-labile group of the carboxylic acid is protected by the benzyl alcohol of the 3rd order, and the activation energy of the deprotection reaction by the acid catalyst is very low, and the deprotection reaction proceeds even at a temperature of about 50°C. When a polymer having an acid-labile group with a very low activation energy of the deprotection reaction is used as a base polymer, the post-exposure bake (PEB) temperature is too low and the uniformity of the temperature is difficult to control, or the control of the acid diffusion becomes difficult. When the acid diffusion distance cannot be controlled, the size uniformity of the pattern after development, the limit resolution are reduced. In order to control the acid diffusion, the PEB temperature needs to be appropriate, and a range of about 80 to 100°C is appropriate.

[0253] Another problem when using a low-activation energy protecting group is that the protecting group is detached during polymerization, for example, when a polymer in which a photoacid generator (PAG) is copolymerized. The PAG of the onium salt is essentially neutral, but when a part of the onium salt is dissociated due to heating during polymerization, or a repeating unit having a phenolic hydroxyl group is also copolymerized, a proton exchange reaction of the phenolic hydroxyl group and the cation of the PAG occurs, resulting in the generation of an acid and causing the deprotection of the protecting group. Especially when a low-activation energy protecting group is used, the deprotection during polymerization is significant.

[0254] As described above, the acid-labile group of the carboxylic acid protected by the benzyl alcohol of the 3rd order has a benzene ring, and thus has the advantage of excellent etching resistance, but when a PAG is copolymerized, detachment occurs during polymerization. If an electron-attracting group is attached to the benzene ring, the activation energy of the deprotection increases. It is believed that this is because the stability of the benzyl cation of the intermediate of the deprotection decreases due to the electron-attracting group. It is possible to optimize by attaching an electron-attracting group to a very easily deprotected protecting group to reduce the reactivity of the deprotection reaction.

[0255] By introducing a fluorine atom to the protecting group, resolution improvement is expected due to swelling inhibition during alkali development. However, if a fluorine atom is introduced to the acid-labile group of the tertiary alkyl group, the stability of the intermediate cation of the deprotection reaction becomes very low due to the electron-attracting effect of the fluorine atom, and thus the generation of an olefin does not occur, and the deprotection reaction does not occur. However, the tertiary acid-labile group having an aromatic group containing a fluorine atom is most suitable for the stability of the intermediate cation, and will exhibit moderate deprotection reactivity, and will also achieve an etching resistance improvement effect.

[0256] From the above, in order to suppress acid diffusion and improve the dissolution contrast and etching resistance, by using the aforementioned polymer as a base polymer of a positive resist composition, particularly as a base polymer of a chemically amplified positive resist composition, the contrast of the alkali dissolution rate before and after exposure will be greatly improved, the effect of suppressing acid diffusion is high and has high resolution, and the pattern shape and LER after exposure are good, and will exhibit more excellent etching resistance.

[0257] The repeating unit A2 is preferably introduced in a range of 2 to 40 mol% of the total repeating units of the polymer contained in the base polymer, the repeating unit A3 is preferably introduced in a range of 2 to 40 mol% of the total repeating units of the polymer contained in the base polymer, and the total of the repeating units A2 and A3 is preferably introduced in a range of 8 to 60 mol%, more preferably 10 to 40 mol% of the total repeating units of the polymer contained in the base polymer.

[0258] With respect to the design of the aforementioned base polymer, by being designed to mix the two types of acid-labile groups in which the phenolic hydroxyl group and the carboxyl group are protected, the dissolution rate of the exposed portion will be increased using the carboxylate skeleton while maintaining the pattern rigidity due to the phenol skeleton, and thus the resolution of the exposed portion will be maintained and the dissolution contrast between the exposed portion and the unexposed portion will be optimized. Thereby, a pattern with little influence of development load and little size difference regardless of pattern density can be obtained. Since the development conditions are stronger than the conditions for processing a wafer substrate when making a photomask, a pattern with good resolution and little size difference in which the influence of development load is suppressed is required, and thus the chemically amplified positive resist composition of the present application is particularly suitable for photomask substrate processing.

[0259] The polymer contained in the aforementioned base polymer preferably further contains at least one selected from the repeating unit represented by the following formula (B1) (hereinafter also referred to as repeating unit B1.), the repeating unit represented by the following formula (B2) (hereinafter also referred to as repeating unit B2.), and the repeating unit represented by the following formula (B3) (hereinafter also referred to as repeating unit B3.).

[0260] [Chemical Formula 58]

[0261]

[0262] In formulae (Bl) and (B2), g and h are each independently an integer of 0 to 4.

[0263] In formulae (Bl) and (B2), R 11 and R 12 are each independently a hydroxyl group, a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which can also be substituted with a halogen atom, a saturated hydrocarbon group having 1 to 8 carbon atoms which can also be substituted with a halogen atom, or a saturated hydrocarbon oxy group having 1 to 8 carbon atoms which can also be substituted with a halogen atom. The aforementioned saturated hydrocarbon group, saturated hydrocarbon oxy group and saturated hydrocarbon carbonyloxy group can be linear, branched or cyclic. When g is 2 or more, each R 11 may be the same or different. When h is 2 or more, each R 12 may be the same or different.

[0264] In formula (B3), R A are the same as described above. i is an integer of 0 to 5. j is an integer of 0 to 2.

[0265] In formula (B3), R 13 is an acetyl group, a saturated hydrocarbon group having 1 to 20 carbon atoms, a saturated hydrocarbon oxy group having 1 to 20 carbon atoms, a saturated hydrocarbon carbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbon oxyhydrocarbon group having 2 to 20 carbon atoms, a saturated hydrocarbon thiohydrocarbon 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 can also be a hydroxyl group. The aforementioned saturated hydrocarbon group, saturated hydrocarbon oxy group, saturated hydrocarbon carbonyloxy group, saturated hydrocarbon oxyhydrocarbon group and saturated hydrocarbon thiohydrocarbon group can be linear, branched or cyclic. When i is 2 or more, each R 13 may be the same or different.

[0266] In formula (B3), X 4 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. * is an atomic bond between the carbon atom of the main chain.

[0267] In formula (B3), 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 can also be substituted with -O-. The aforementioned saturated hydrocarbylene group can be linear, branched or cyclic, and specific examples thereof can be exemplified by the groups described in the explanation of A 1 are the same groups as described in the explanation of A

[0268] When repeating units Bl to B3 are used, the effect of improving the EB irradiation resistance during etching and pattern inspection, in addition to the etching resistance of the aromatic ring, can be obtained due to the ring structure added to the main chain.

[0269] As for the repeating units B1 to B3, it is preferable that the total repeating units of the polymer contained in the base polymer have 5 mol% or more of the repeating units introduced therein in order to obtain the effect of improving the etching resistance. Also, it is preferable that the repeating units B1 to B3 be introduced in the total repeating units constituting the base polymer in an amount of 30 mol% or less, and more preferably 25 mol% or less. When the functional group is not a hydroxyl group or is a hydroxyl group other than the one described above, the amount of the repeating units introduced is desirably 30 mol% or less, because there is no risk of developing defects. One of the repeating units B1 to B3 can be used alone or two or more of them can be used in combination.

[0270] It is desirable that the total repeating units of the polymer contained in the base polymer have 50 mol% or more of the repeating units A1 and at least one repeating unit selected from the repeating units B1 to B3, more desirably 60 mol% or more, and even more desirably 70 mol% or more.

[0271] It is desirable that the total repeating units of the polymer contained in the base polymer have 65 mol% or more of the repeating units having an aromatic ring skeleton, more desirably 85 mol% or more, and even more desirably all the units be the repeating units having an aromatic ring skeleton.

[0272] It is desirable that the total repeating units of the polymer contained in the base polymer have 80 mol% or more of the repeating units A1, the repeating units A2, the repeating units A3, and at least one repeating unit selected from the repeating units B1 to B3, and more desirably 90 mol% or more.

[0273] It is desirable that the polymer contained in the base polymer not contain a repeating unit that generates an acid upon exposure. That is, it is desirable that the polymer contained in the base polymer not be a so-called PAG-binding polymer. In the design of the present application, a repeating unit that generates an acid upon exposure causes swelling in alkali development and has a risk of degrading the resolution.

[0274] The aforementioned polymer can also contain a (meth)acrylate unit protected by an acid-labile group, a (meth)acrylate unit having a lactone structure, a hydroxyl group other than a phenolic hydroxyl group, or the like, which is an adhesion-imparting group. These repeating units can be used to adjust the properties of the resist film, but the polymer can also not contain these units.

[0275] The aforementioned (meth)acrylate unit having an adhesion-imparting group is, for example, a repeating unit represented by the following formula (B4) (hereinafter also referred to as repeating unit B4), a repeating unit represented by the following formula (B5) (hereinafter also referred to as repeating unit B5), and a repeating unit represented by the following formula (B6) (hereinafter also referred to as repeating unit B6). These units do not exhibit acidity and can be used as units that impart adhesion to a substrate and adjust the solubility.

[0276] [Chemical Formula 59]

[0277]

[0278] In formulae (B4) to (B6), R A is the same as described above. R 14 is -O- or methylene. R 15 is a hydrogen atom or a hydroxyl group. R 16 is a saturated hydrocarbon group having 1 to 4 carbon atoms. k is an integer of 0 to 3.

[0279] When the repeating units B4 to B6 are contained, the content thereof is preferably 0 to 20 mol% and more preferably 0 to 10 mol% in the total repeating units of the polymer contained in the base polymer described above. One kind of the repeating units B4 to B6 can be used alone or two or more kinds thereof can be used in combination.

[0280] The polymer described above can be synthesized by copolymerizing each monomer protected with a protecting group as necessary by a publicly known method, followed by a deprotection reaction as necessary. The copolymerization reaction is not particularly limited and is preferably radical polymerization, anionic polymerization. These methods can be referred to Japanese Patent Application Publication No. 2004-115630.

[0281] The polymer described above preferably has a weight average molecular weight (Mw) of 1,000 to 50,000 and more preferably 2,000 to 20,000. If the Mw is 1,000 or more, there is no risk of the resolution being reduced and the LER being deteriorated due to the top of the pattern being rounded as conventionally known. On the other hand, if the Mw is 50,000 or less, there is no risk of the LER being deteriorated when a pattern having a line width of 100 nm or less is formed, in particular. In the present application, the Mw is a polystyrene conversion value measured by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

[0282] The polymer described above preferably has a molecular weight distribution (Mw / Mn) of 1.0 to 2.0, more preferably 1.0 to 1.9, and still more preferably 1.0 to 1.8. In this case, when the molecular weight distribution is narrow, there is no risk of foreign matter appearing on the pattern after development or the shape of the pattern being deteriorated.

[0283] Further, in the aforementioned base polymer, it is desirable that the dissolution rate in an alkali developer be 10 nm / min or less, more desirable 7 nm / min or less, and even more desirable 5 nm / min or less. In the advanced era, when the coated film on a substrate is in the thin film region (100 nm or less), the influence of the loss of the pattern film due to alkali development increases, and when the alkali dissolution rate of the polymer is greater than 10 nm / min, the pattern collapses and a fine pattern cannot be formed. In particular, in the production of a photomask in which no defects are required, development is strongly desired, and thus this is particularly significant. Further, in the present application, the alkali dissolution rate of the base polymer is calculated from the amount of film loss when a film having a thickness of 1,000 nm is formed by spin coating a polymer solution (polymer concentration: 16.7 mass%, solvent: propylene glycol monomethyl ether acetate (PGMEA)) on an 8-inch silicon wafer at 100°C for 90 seconds, and then developing the film with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH) at 23°C for 100 seconds.

[0284] [Polymer containing fluorine atom]

[0285] The chemically amplified positive resist composition of the present application can also contain a polymer containing a fluorine atom containing at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (C1), a repeating unit represented by the following formula (C2), a repeating unit represented by the following formula (C3), and a repeating unit represented by the following formula (C4) (hereinafter, each also referred to as repeating unit C1, C2, C3, and C4), and can further contain at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (C5) and a repeating unit represented by the following formula (C6) (hereinafter, each also referred to as repeating unit C5 and C6). The aforementioned polymer containing a fluorine atom also has the effect of a surfactant, and thus can prevent the reattachment of insolubles to the substrate that can occur during development, and also exerts an effect against development defects.

[0286] [Chemical 60]

[0287]

[0288] In the formulas (C1) to (C6), R D each independently is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R E each independently is a hydrogen atom or a methyl group. R 101 , R 102 , R 104 , and R 105 each independently is a hydrogen atom or a saturated hydrocarbon group having a carbon number of 1 to 10. R 103 , R106 , R 107 , and R 108 each independently is a hydrogen atom, a hydrocarbon group having a carbon number of 1 to 15, a fluorinated hydrocarbon group having a carbon number of 1 to 15, or an acid-labile group, R 103 , R 106 , R 107 , and R 108 when a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group can also be inserted between carbon-carbon bonds. R 109 is a hydrogen atom, or a linear or branched hydrocarbon group having a carbon number of 1 to 5, in which a heteroatom-containing group can also be inserted between carbon-carbon bonds. R 110 is a linear or branched hydrocarbon group having a carbon number of 1 to 5, in which a heteroatom-containing group can also be inserted between carbon-carbon bonds. R 111 is a saturated hydrocarbon group having a carbon number of 1 to 20, in which at least one hydrogen atom is replaced with a fluorine atom, and a part of -CH2- constituting the aforementioned saturated hydrocarbon group can also be replaced with an ester bond or an ether bond. 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 (m + 1)-valent hydrocarbon group having a carbon number of 1 to 20, or a (m + 1)-valent fluorinated hydrocarbon group having a carbon number of 1 to 20. Z 2 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * is an atomic bond between a carbon atom of the main chain. Z 3 is a single bond, -O-, *-C(=O)-O-Z 31 -Z 32 -, or *-C(=O)-NH-Z 31 -Z 32 -. Z 31 is a single bond or a saturated hydrocarbylene group having a carbon number of 1 to 10. Z 32 is a single bond, an ester bond, an ether bond, or a sulfonamide bond. * is an atomic bond between a carbon atom of the main chain.

[0289] In formulae (C1) and (C2), R 101 , R 102 , R 104 , and R 105 represent a saturated hydrocarbon group having a carbon number of 1 to 10, which can be exemplified by alkyl groups having a carbon number of 1 to 10 such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, and an n-decyl group; and cyclic saturated hydrocarbon groups having a carbon number of 3 to 10 such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and an adamantyl group. Among these, a saturated hydrocarbon group having a carbon number of 1 to 6 is preferable.

[0290] In formulae (C1) to (C4), R 103 , R 106 , R 107 , and R108 Examples of hydrocarbon groups with 1 to 15 carbon atoms include alkyl groups with 1 to 15 carbon atoms, alkenyl groups with 2 to 15 carbon atoms, and alkynyl groups with 2 to 15 carbon atoms, but alkyl groups with 1 to 15 carbon atoms are preferred. Further examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, and n-pentadecayl. Furthermore, fluorinated hydrocarbon groups can be groups in which some or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbon groups are replaced by fluorine atoms.

[0291] In equation (C4), Z 1 The hydrocarbon groups with a valence of (m+1) carbon atoms, representing 1 to 20 carbon atoms, can be alkyl groups with 1 to 20 carbon atoms or cyclic saturated hydrocarbon groups with 3 to 20 carbon atoms that have removed m hydrogen atoms. Also, Z 1 The fluorinated hydrocarbon groups with a carbon number of 1 to 20 and a valence of (m+1) can be listed as groups in which at least one hydrogen atom of the aforementioned hydrocarbon group with a valence of (m+1) is replaced by a fluorine atom.

[0292] Specific examples of repeated units C1 to C4 can be listed below, but are not limited to these. Also, in the following formula, R... D Same as above.

[0293] [Chemistry 61]

[0294]

[0295] [Chemistry 62]

[0296]

[0297] [Chemistry 63]

[0298]

[0299] In equation (C5), R 109 and R 110 Examples of hydrocarbon groups with 1 to 5 carbon atoms include alkyl, alkenyl, and ynyl groups, but alkyl is preferred. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and n-pentyl. Furthermore, heteroatoms such as oxygen, sulfur, and nitrogen atoms may be inserted between the carbon-carbon bonds of these groups.

[0300] In equation (C5), -OR 109 It is preferable to have a hydrophilic group. In this case, R 109 It is preferable to have hydrogen atoms or alkyl groups with 1 to 5 carbon atoms that have oxygen atoms inserted between carbon-carbon bonds.

[0301] In equation (C5), Z 2-C(=O)-O- or *-C(=O)-NH- is preferable. Further, R E is preferably a methyl group. By Z 2 The presence of a carbonyl group in R E If it is a methyl group, it becomes a rigid polymer having a higher glass transition temperature (Tg), and thus diffusion of the acid is inhibited. Thus, the temporal stability of the resist film becomes good, and resolution and pattern shape are not deteriorated.

[0302] The repeating unit C5 can be exemplified as follows, but is not limited to these. Further, in the following formula, R E The same as described above.

[0303] [Chemical Formula 64]

[0304]

[0305] [Chemical Formula 65]

[0306]

[0307] In formula (C6), Z 3 The saturated hydrocarbylene group having 1 to 10 carbons represented by Z

[0308] In formula (C6), R 111 The saturated hydrocarbyl group having 1 to 20 carbons in which at least one hydrogen atom is substituted with a fluorine atom represented by R

[0309] The repeating unit C6 can be exemplified as follows, but is not limited to these. Further, in the following formula, R E The same as described above.

[0310] [Chemical Formula 66]

[0311]

[0312] [Chemical Formula 67]

[0313]

[0314] [Chemical Formula 68]

[0315]

[0316] [Chemical 69]

[0317]

[0318] The content of the repeating units C1 to C4 is preferably 15 to 95 mol% and more preferably 20 to 85 mol% of the total repeating units of the aforementioned fluorine atom-containing polymer. The content of the repeating units C5 and / or C6 is preferably 5 to 85 mol% and more preferably 15 to 80 mol% of the total repeating units of the aforementioned fluorine atom-containing polymer. The repeating units C1 to C6 can be used alone or in combination of two or more.

[0319] The aforementioned fluorine atom-containing polymer can contain other repeating units in addition to the aforementioned repeating units. Such repeating units can include the repeating units described in paragraphs

[0046] to

[0078] of Japanese Patent Application Publication No. 2014-177407, and the like. When the aforementioned fluorine atom-containing polymer contains other repeating units, the content of the other repeating units is preferably 50 mol% or less of the total repeating units of the aforementioned fluorine atom-containing polymer.

[0320] The aforementioned fluorine atom-containing polymer can be synthesized by copolymerizing each monomer, which is optionally protected with a protecting group, by a known method, and then performing a deprotection reaction as necessary. The copolymerization reaction is not particularly limited, and is preferably radical polymerization, anionic polymerization. For these methods, reference can be made to Japanese Patent Application Publication No. 2004-115630.

[0321] The aforementioned fluorine atom-containing polymer preferably has a Mw of 2,000 to 50,000 and more preferably 3,000 to 20,000. If the Mw is less than 2,000, acid diffusion is promoted, and there is a possibility of resolution degradation and deterioration of the temporal stability. If the Mw is too large, the solubility in a solvent decreases, and there is a possibility of defects in coating. Also, the aforementioned fluorine atom-containing polymer preferably has a Mw / Mn of 1.0 to 2.2 and more preferably 1.0 to 1.7.

[0322] When the chemical amplification positive resist composition of the present application contains the aforementioned fluorine atom-containing polymer, the content thereof is preferably 0.01 to 30 parts by mass and more preferably 0.1 to 20 parts by mass and even more preferably 0.5 to 10 parts by mass relative to 80 parts by mass of the base polymer.

[0323] [Organic solvent]

[0324] The chemical amplification positive resist composition of the present application can also contain an organic solvent. The aforementioned organic solvent is not particularly limited as long as each component is soluble in the organic solvent. Examples of such an organic solvent include ketones such as cyclohexanone, methyl-2-n-pentyl ketone, and the like described in paragraphs

[0144] to

[0145] of Japanese Patent Application Publication No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, diacetone alcohol, and the like; ethers such as propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, and the like; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate (EL), ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, t-butyl acetate, t-butyl propionate, propylene glycol mono-t-butyl ether acetate, and the like; lactones such as γ-butyrolactone; and mixed solvents of these. When an acetal-based acid-labile group is used, a high-boiling alcohol-based solvent can also be added in order to accelerate the deprotection reaction of the acetal, and specifically, diethylene glycol, propylene glycol, glycerol, 1,4-butanediol, 1,3-butanediol, and the like can also be added.

[0325] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, PGME, cyclohexanone, EL, γ-butyrolactone, and mixed solvents of these are preferable.

[0326] When the chemical amplification positive resist composition of the present application contains the aforementioned organic solvent, the content is preferably 200 to 10,000 parts by mass and more preferably 400 to 5,000 parts by mass relative to 80 parts by mass of the base polymer. One kind of organic solvent can be used alone or two or more kinds of organic solvents can be used in combination.

[0327] [Photoacid Generator]

[0328] The chemical amplification positive resist composition of the present application can also contain a photoacid generator. The aforementioned photoacid generator is not particularly limited as long as it is a compound that generates an acid upon irradiation of high-energy rays, and examples include sulfonium salts, iodonium salts, sulfonyl diazomethane, N-sulfonyloxy imides, oxime-O-sulfonic acid ester type acid generators, and the like.

[0329] Specific examples of the aforementioned photoacid generator can include nonafluorobutanesulfonate, partially fluorinated sulfonate salts described in paragraphs

[0247] to

[0251] of Japanese Patent Application Publication No. 2012-189977, partially fluorinated sulfonate salts described in paragraphs

[0261] to

[0265] of Japanese Patent Application Publication No. 2013-101271, photoacid generators described in paragraphs

[0122] to

[0142] of Japanese Patent Application Publication No. 2008-111103, paragraphs

[0080] to

[0081] of Japanese Patent Application Publication No. 2010-215608, and the like. Among the aforementioned specific examples, photoacid generators of the arylsulfonate type or the alkanesulfonate type generate an acid of moderate strength that serves to deprotect the acid-labile group of the repeating unit represented by formula (A2) or (A3), and thus are desirable.

[0330] Such a photoacid generator is preferably a compound having an anion of the structure shown below.

[0331] [Chem. 70]

[0332]

[0333] [Chem. 71]

[0334]

[0335] [Chem. 72]

[0336]

[0337] [Chem. 73]

[0338]

[0339] [Chem. 74]

[0340]

[0341] [Chem. 75]

[0342]

[0343] [Chem. 76]

[0344]

[0345] As a cation paired with the aforementioned anion, a sulfonium cation represented by the following formula (D) or a sulfoxonium cation represented by the following formula (E) is preferable.

[0346] [Chem. 77]

[0347]

[0348] In formulae (D) and (E), R 201 ~ R205 each independently is a halogen atom or a hydrocarbon group having 1 to 20 carbon atoms which can also contain a hetero atom.

[0349] The aforementioned halogen atom can include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like.

[0350] The aforementioned hydrocarbon group having 1 to 20 carbon atoms can be either saturated or unsaturated, and can be either linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a t-butyl group, a t-amyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, an n-decyl group, and the like; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms such as a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, a tricyclo[5.2.1.02,6]decyl group, an adamantyl group, an adamantylmethyl group, and the like; aryl groups having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, an anthryl group, and the like. Also, a part or all of the hydrogen atoms of the aforementioned hydrocarbon group can be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, and the like, and a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, and the like can also be inserted between carbon-carbon bonds of the aforementioned hydrocarbon group, as a result of which a hydroxyl 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 sulfonate ester bond, a carbonate ester bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, and the like can also be contained.

[0351] Also, R 201 and R 202 may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. Examples of the ring formed at this time include the following.

[0352] [Chemical Formula 78]

[0353]

[0354] in the formula, the dotted line is a bond to the atom of R 203 .

[0355] Specific examples of the sulfonium cation represented by formula (D) include the following, but are not limited thereto.

[0356] [Chemical Formula 79]

[0357]

[0358] [Chemical Formula 80]

[0359]

[0360] [Chemical Formula 81]

[0361]

[0362] [Chemical Formula 82]

[0363]

[0364] [Chemical Formula 83]

[0365]

[0366] [Chemical Formula 84]

[0367]

[0368] [Chemical Formula 85]

[0369]

[0370] [Chemical Formula 86]

[0371]

[0372] [Chemical Formula 87]

[0373]

[0374] [Chemical Formula 88]

[0375]

[0376] [Chemical Formula 89]

[0377]

[0378] [Chemical Formula 90]

[0379]

[0380] [Chemical Formula 91]

[0381]

[0382] [Chemical Formula 92]

[0383]

[0384] [Chemical Formula 93]

[0385]

[0386] [Chemical Formula 94]

[0387]

[0388] [Chemical Formula 95]

[0389]

[0390] [Chemical Formula 96]

[0391]

[0392] [Chem. 97]

[0393]

[0394] [Chem. 98]

[0395]

[0396] [Chem. 99]

[0397]

[0398] [Chem. 100]

[0399]

[0400] Specific examples of the mesityl cation represented by formula (E) can be listed as follows, but are not limited to these.

[0401] [Chem. 101]

[0402]

[0403] [Chem. 102]

[0404]

[0405] The acid generated by the aforementioned photoacid generator is preferably an acid having a pKa of 2.0 or more, more preferably. Also, the upper limit of the pKa is preferably 2.0. Also, the pKa value is calculated using the pKa database in ACD / Chemsketch ver: 9.04 manufactured by Advanced Chemistry Development, Inc.

[0406] When the chemically amplified positive resist composition of the present application contains a photoacid generator, the content thereof is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, relative to 80 parts by mass of the aforementioned base polymer. The aforementioned photoacid generator can be used alone or in combination of two or more.

[0407] [Quencher]

[0408] The chemical amplification positive resist composition of the present application preferably contains a quencher. The aforementioned quencher can include known types of basic compounds. The known types of basic compounds can include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl 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 Japanese Patent Application Publication No. 2008-111103, and in particular, amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group, a sulfonate bond, or the like, or the compounds having a carbamate group described in Japanese Patent No. 3790649, and the like are preferable. Examples of the aforementioned quencher 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 diffusion rate of the acid in the resist film can be more suppressed, or the shape can be corrected.

[0409] Further, the aforementioned quencher can include sulfonium salts, phosphonium salts, ammonium salts, and the like of carboxylic acids having no fluorine at the α-position, as described in Japanese Patent Application Publication No. 2008-158339. The sulfonic acid, imide acid, or methylated acid having fluorine at the α-position is necessary for deprotection of the acid-labile group, but by salt exchange with the salt of the carboxylic acid having no fluorine at the α-position, the carboxylic acid having no fluorine at the α-position is released. The carboxylic acid having no fluorine at the α-position hardly undergoes a deprotection reaction, and thus functions as a quencher.

[0410] The phosphonium salt of the carboxylic acid having no fluorine at the α-position is, for example, a phosphonium salt represented by the following formula (F1).

[0411] [Chemical Formula 103]

[0412] R 301 -CO2 - Mq + (F1)

[0413] In formula (F1), R 301 is a hydrogen atom or a hydrocarbon group having 1 to 40 carbon atoms which can also contain a heteroatom, but the hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is replaced with a fluorine atom or a fluoroalkyl group.

[0414] The aforementioned hydrocarbon group can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples thereof can include alkyl groups having 1 to 40 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, t-butyl, n-pentyl, t-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, and the like; cyclic alkyl groups such as cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, tricyclo[5.2.1.02,6 alkenyl group having a carbon number of 2 to 40; a cyclohexenyl group and the like aliphatic unsaturated cyclic hydrocarbon group having a carbon number of 3 to 40; a phenyl group, a naphthyl group, an alkylphenyl group (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-n-butylphenyl group and the like), a dialkylphenyl group (2,4-dimethylphenyl group, 2,4,6-triisopropylphenyl group and the like), an alkylnaphthyl group (methylnaphthyl group, ethylnaphthyl group and the like), a dialkylnaphthyl group (dimethylnaphthyl group, diethylnaphthyl group and the like) and the like aryl group having a carbon number of 6 to 40; a benzyl group, a 1-phenylethyl group, a 2-phenylethyl group and the like aralkyl group having a carbon number of 7 to 40 and the like.

[0415] Further, a part of the hydrogen atoms of these groups can be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom and the like, a part of the carbon atoms of these groups can be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom and the like, as a result of which a hydroxyl group, a cyano group, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=0)-0-C(=0)-), a haloalkyl group and the like can be contained. The hydrocarbon group containing a hetero atom can be exemplified by a heteroaryl group such as a thienyl group; an alkoxyphenyl group such as a 4-hydroxyphenyl group, a 4-methoxyphenyl group, a 3-methoxyphenyl group, a 2-methoxyphenyl group, a 4-ethoxyphenyl group, a 4-tert-butoxyphenyl group, a 3-tert-butoxyphenyl group and the like; an alkylnaphthyl group such as a methoxynaphthyl group, an ethoxynaphthyl group, an n-propyloxynaphthyl group, an n-butyloxynaphthyl group and the like; a dialkylnaphthyl group such as a dimethoxynaphthyl group, a diethoxynaphthyl group and the like; an aryloxoalkyl group such as a 2-aryl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, a 2-(2-naphthyl)-2-oxoethyl group and the like.

[0416] In formula (F1), Mq + is an onium cation. The aforementioned onium cation is preferably a sulfonium cation, a sulfoxonium cation or an ammonium cation, more preferably a sulfonium cation or a sulfoxonium cation. The aforementioned sulfonium cation can be exemplified by the same examples as exemplified for the sulfonium cation represented by formula (D). The aforementioned sulfoxonium cation can be exemplified by the same examples as exemplified for the sulfoxonium cation represented by formula (E).

[0417] The anion of the salt represented by formula (F1) can be exemplified by the following but is not limited to these.

[0418] [Chemical Formula 104]

[0419]

[0420] [Chemical Formula 105]

[0421]

[0422] [Chemical Formula 106]

[0423]

[0424] The aforementioned quencher is also preferably a sulfonium salt of a carboxylic acid containing an iodinated benzene ring represented by the following formula (F2).

[0425] [Chemical Formula 107]

[0426]

[0427] In formula (F2), R 401 one or more of a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or a hydrogen atom can be substituted with a halogen atom, a saturated hydrocarbon group having 1 to 6 carbons, a saturated hydrocarbonoxy group having 1 to 6 carbons, a saturated hydrocarbonyloxy group having 2 to 6 carbons, or a saturated hydrocarbonylsulfonyloxy group having 1 to 4 carbons, or -N(R 401A )-C(=O)-R 401B or -N(R 401A )-C(=O)-O-R 401B R 401A is a hydrogen atom or a saturated hydrocarbon group having 1 to 6 carbons. R 401B is a saturated hydrocarbon group having 1 to 6 carbons or an unsaturated aliphatic hydrocarbon group having 2 to 8 carbons.

[0428] In formula (F2), p is an integer of 1 to 5. q is an integer of 0 to 3. r is an integer of 1 to 3. L 1 is a single bond or a (r+1)-valent linking group having 1 to 20 carbons, and can also contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxyl group, and a carboxyl group. The aforementioned saturated hydrocarbon group, saturated hydrocarbonoxy group, saturated hydrocarbonyloxy group, and saturated hydrocarbonylsulfonyloxy group can be linear, branched, or cyclic. When q and / or r is 2 or more, each R 401 may be the same or different.

[0429] In formula (F2), R 402 , R 403 , and R 404each independently is a halogen atom, or a hydrocarbon group having a carbon number of 1 to 20 which can also contain a hetero atom. The aforementioned hydrocarbon group can be either saturated or unsaturated, and can be either linear, branched, or cyclic. Specific examples thereof include an alkyl group having a carbon number of 1 to 20, an alkenyl group having a carbon number of 2 to 20, an aryl group having a carbon number of 6 to 20, an aralkyl group having a carbon number of 7 to 20, and the like. Also, part or all of the hydrogen atoms of these groups can be substituted with a hydroxyl group, a carboxyl group, a halogen atom, an oxo group, a cyano group, a nitro group, a sultine group, a sulfone group, or a group containing a sulfonium salt, and part of the carbon atoms of these groups can be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond, or a sulfonate bond. Also, R 402 and R 403 may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded.

[0430] Specific examples of the compound represented by formula (F2) include those described in Japanese Patent Application Publication No. 2017-219836. The compound represented by formula (F2) has high absorption and high sensitization effect, and also has high acid diffusion control effect.

[0431] The aforementioned quencher can also use a carboxylate-type compound containing a nitrogen atom represented by the following formula (F3).

[0432] [Chemical Formula 108]

[0433]

[0434] In formula (F3), R 501 to R 504 each independently is a hydrogen atom, -L 2 -CO2 - , or a hydrocarbon group having a carbon number of 1 to 20 which can also contain a hetero atom. R 501 and R 502 , R 502 and R 503 , or R 503 and R 504 may also be bonded to each other and form a ring together with the carbon atom to which they are bonded. L 2 is a single bond or a hydrocarbylene group having a carbon number of 1 to 20 which can also contain a hetero atom. R 505 is a hydrogen atom or a hydrocarbon group having a carbon number of 1 to 20 which can also contain a hetero atom.

[0435] In formula (F3), the ring R is a ring having a carbon number of 2 to 6 which contains the carbon atom and the nitrogen atom in the formula, and part or all of the hydrogen atoms bonded to the carbon atoms of the ring can also be substituted with a hydrocarbon group having a carbon number of 1 to 20, or -L 2 -CO2 -Alternatively, a part of the carbon atoms of the ring can be substituted with a sulfur atom, an oxygen atom, or a nitrogen atom. The aforementioned ring can be an alicyclic ring or an aromatic ring, and further, a 5-membered ring or a 6-membered ring is preferable, and specific examples thereof can include a pyridine ring, a pyrrole ring, a pyrrolidine ring, a piperidine ring, a pyrazole ring, an imidazolidine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, an imidazolidine ring, an oxazole ring, a thiazole ring, a morpholine ring, a thiazine ring, a triazole ring, and the like.

[0436] The onium salt of the carboxylic acid represented by formula (F3) has at least one -L 2 -CO2 - group. That is, at least one of R 501 ~R 504 is -L 2 -CO2 - , and / or at least one of the hydrogen atoms bonded to the carbon atoms of the ring R is substituted with -L 2 -CO2 - .

[0437] In formula (F3), Q + is a sulfonium cation, a sulfoxonium cation, or an ammonium cation, but a sulfonium cation is preferable. The aforementioned sulfonium cation can include the same examples as those exemplified for the sulfonium cation represented by formula (D).

[0438] The anion of the compound represented by formula (F3) can include the following, but is not limited thereto.

[0439] [Chemical Formula 109]

[0440]

[0441] [Chemical Formula 110]

[0442]

[0443] [Chemical Formula 111]

[0444]

[0445] [Chemical Formula 112]

[0446]

[0447] [Chemical Formula 113]

[0448]

[0449] [Chemical Formula 114]

[0450]

[0451] Further, a betaine-type compound of a weak acid can also be used as the aforementioned quencher. Specific examples thereof can include the following, but are not limited thereto.

[0452] [Patent Literature 1]

[0453]

[0454] As the aforementioned quencher, a polymer-type quencher described in Japanese Patent Application Publication No. 2008-239918 can be further exemplified. It improves the rectangularity of a resist pattern by aligning on the surface of a resist film. The polymer-type quencher also has an effect of preventing film loss of a pattern and rounding of a top of a pattern when a protective film for immersion exposure is used.

[0455] When the chemical amplification positive resist composition of the present application contains a quencher, the content thereof is preferably 0 to 50 parts by mass, more preferably 0.1 to 40 parts by mass, relative to 80 parts by mass of the base polymer. The aforementioned quencher can be used alone or in combination of two or more.

[0456] [Surfactant]

[0457] In order to improve the coating properties on a substrate, the chemical amplification positive resist composition of the present application can also contain a conventional surfactant. When a surfactant is used, there are many examples as described in Japanese Patent Application Publication No. 2004-115630, and many surfactants are known, and they can be selected by reference. The content of the aforementioned surfactant is preferably 0 to 5 parts by mass, relative to 80 parts by mass of the aforementioned base polymer. Also, when the aforementioned fluorine atom-containing polymer is contained in the chemical amplification positive resist composition of the present application, the aforementioned fluorine atom-containing polymer also functions as a surfactant, and therefore the aforementioned surfactant can also not be contained.

[0458] In terms of the design of the chemical amplification positive resist composition of the present application, the dissolution rate of the overexposed portion of the obtained resist film to an alkali developer is preferably 50 nm / sec or more, more preferably 100 nm / sec or more, and still more preferably 200 nm / sec or more, from the viewpoint of improving the development load. By being 50 nm / sec or more, even if there is a difference in the pattern layout in a dense pattern, the alkali developer can be dissolved uniformly, and the line width variation can be reduced. Also, in the present application, the dissolution rate of the overexposed portion is a value calculated from the amount of energy at which the deprotection reaction of a polymer is completed, and is a value obtained by performing exposure with a KrF excimer laser after spin coating the chemical amplification positive resist composition of the present application on an 8-inch silicon wafer, baking at 110°C for 60 seconds to form a resist film having a thickness of 90 nm, and baking at 110°C for 60 seconds, and then developing with a 2.38 mass% TMAH aqueous solution at 23°C using a resist development analyzer.

[0459] Also, the dissolution rate of the unexposed portion of the resist film obtained from the chemical amplification positive resist composition of the present application with respect to the alkali developer is preferably 10 nm / min or less, more preferably 8 nm / min or less, and even more preferably 6 nm / min or less. When the aforementioned resist film belongs to the thin film region (100 nm or less), the effect of pattern film loss with respect to the alkali developer increases, and when the dissolution rate of the unexposed portion is greater than 10 nm / min, the pattern collapses and it becomes impossible to form a fine pattern. In particular, when defect-free photomask production is required, the development process has a strong tendency, and thus it is significant. Also, the dissolution rate of the unexposed portion is a value calculated from the amount of film loss at the time when a 6-inch silicon wafer is spin-coated with the chemical amplification positive resist composition of the present application, baked at 110°C for 240 seconds to form a resist film having a thickness of 80 nm, and then developed with a 2.38 mass% TMAH aqueous solution at 23°C for 80 seconds.

[0460] [Resist pattern forming method]

[0461] The resist pattern forming method of the present application includes the following steps: forming a resist film on a substrate using the aforementioned chemical amplification positive resist composition; exposing the aforementioned resist film to a pattern using a high-energy ray (i.e., exposing the aforementioned resist film to light using a high-energy ray), and developing the aforementioned resist film that has been exposed to the pattern using an alkali developer.

[0462] The aforementioned substrate can be, for example, a substrate for integrated circuit production (Si, SiO, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflection film, etc.), or a substrate for mask circuit production (Cr, CrO, CrON, MoSi2, Si, SiO, SiO2, SiON, SiONC, CoTa, NiTa, TaBN, SnO2, etc.), etc. The aforementioned chemical amplification positive resist composition is applied to the aforementioned substrate by spin coating or the like so that the film thickness becomes 0.03 to 2 μm, and it 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.

[0463] Next, the aforementioned resist film is exposed to light and exposed to a pattern using a high-energy ray. The aforementioned high-energy ray can be, for example, ultraviolet light, far ultraviolet light, excimer laser light (KrF, ArF, etc.), EUV, X-ray, γ-ray, synchrotron radiation, EB, etc. In the present application, exposure using EUV or EB is preferable.

[0464] When ultraviolet light, far ultraviolet light, excimer laser light, EUV, X-ray, γ-ray, or synchrotron radiation is used as the aforementioned high-energy ray, exposure is performed using a mask for forming the desired pattern, and the exposure dose is preferably 1 to 500 mJ / cm 2More preferably 10 to 400 mJ / cm 2 When EB is used, in order to form the desired pattern, irradiation is performed directly, and the exposure amount is preferably 1 to 500 μC / cm 2 More preferably 10 to 400 μC / cm 2 .

[0465] In addition to the usual exposure method, the immersion method in which the mask and the resist are immersed can be used as appropriate. In this case, a protective film that is not soluble in water can be used.

[0466] Then, PEB is preferably performed at 60 to 150°C for 1 to 20 minutes, and more preferably at 80 to 140°C for 1 to 10 minutes.

[0467] After that, development is performed using an aqueous alkali solution such as 0.1 to 5 mass%, and more preferably 2 to 3 mass% of TMAH, for 0.1 to 3 minutes, and more preferably 0.5 to 2 minutes, by the usual method such as the dip method, the puddle method, the spray method, and the like, to form the desired pattern on the substrate.

[0468] Further, the chemically amplified positive resist composition of the present application is particularly useful for pattern formation on a substrate having a surface on which it is difficult to achieve adhesion of the resist pattern and thus pattern peeling and pattern collapse are likely to occur. Such a substrate can be exemplified by a substrate on the surface of which metal chromium is sputter-deposited, a substrate on the surface of which a chromium compound containing one or more light elements selected from the group consisting of oxygen, nitrogen, and carbon is deposited, a substrate on the surface of which SiO, SiO x , a tantalum compound, a molybdenum compound, a cobalt compound, a nickel compound, a tungsten compound, a tin compound, and the like. The chemically amplified positive resist composition of the present application is particularly useful when pattern formation is performed using a blank photomask as a substrate. The blank photomask can be of the transmission type or the reflection type.

[0469] According to the resist pattern formation method of the present application, even when a substrate composed of a material such as chromium, silicon, or tantalum on the surface of which the shape of the resist pattern is likely to be affected (for example, a blank photomask) is used, a pattern having high resolution and a small size difference independent of pattern density, in which the influence of development load is suppressed, can be obtained.

[0470] [Examples]

[0471] The following describes synthesis examples, examples, and comparative examples to specifically illustrate the present application, but the present application is not limited to the following examples. The copolymerization composition ratio is a molar ratio, and Mw is the polystyrene-conversion weight average molecular weight determined by GPC.

[0472] [1] Synthesis of polymers

[0473] [Synthesis Example 1-1] Synthesis of polymer P-1

[0474] Under a nitrogen atmosphere, 4-acetyloxy styrene 49.3 g, 4-(l-methyl-l- cyclopentyloxy)styrene 18.9 g, l-methylcyclopentyl methacrylate 11.8 g, dimethyl- 2,2'-azobis(2-methylpropionate) (Fuji Photo Film Co., Ltd. and Wako Pure Chemical Industries, Ltd., trade name V601) 8.6 g, and methyl ethyl ketone 124 g as a solvent were added to a 300 mL dropping cylinder to prepare a solution. Then, in another 500 mL polymerization flask under a nitrogen atmosphere, methyl ethyl ketone 62 g was added, and the above solution was added dropwise over 4 hours while heating to 80°C. After the completion of the dropwise addition, the polymerization temperature was maintained at 80°C, and stirring was continued for 18 hours, and then the temperature was allowed to cool to room temperature. The obtained polymerization solution was added dropwise to 1,300 g of hexane, and the copolymer was separated by filtration. The separated copolymer was washed twice with hexane 500 g. The obtained copolymer was dissolved in a mixed solvent of tetrahydrofuran 144 g and methanol 48 g in a IL flask under a nitrogen atmosphere, and ethanolamine 22.3 g was added, and stirring was performed at 60°C for 3 hours. This reaction solution was concentrated under reduced pressure, and the obtained concentrate was dissolved in a mixed solvent of ethyl acetate 240 g and water 60 g, and the obtained solution was transferred to a separatory funnel, and acetic acid 11.1 g was added, and liquid-liquid separation was performed. The lower layer was removed, and water 60 g and pyridine 14.8 g were added to the obtained organic layer, and liquid-liquid separation was performed. The lower layer was removed, and water 60 g was further added to the obtained organic layer, and water washing liquid-liquid separation was performed a total of 5 times. The organic layer after the liquid-liquid separation was concentrated, and dissolved in acetone 130 g, and the obtained acetone solution was added dropwise to water 1,200 g, and the obtained crystallization precipitate was filtered, washed with water, and suction filtered for 2 hours, and the obtained filtrate was dissolved in acetone 130 g, and the obtained acetone solution was added dropwise to water 1,200 g, and the obtained crystallization precipitate was filtered, washed with water, and dried, and 50.3 g of the target polymer P-1 as a white polymer was obtained. The polymer P-1 was analyzed by 13 C-NMR, 1 H-NMR and GPC, and the following analysis results were obtained.

[0475] [Synthesis Example 1-1] Synthesis of polymer P-1

[0476]

[0477] [Synthesis Examples 1-2 to 1-44, Comparative Synthesis Examples 1-1, 1-2] Synthesis of polymers P-2 to P-44, comparative polymers cP-1, cP-2

[0478] The polymers P-2 to P-44 and comparative polymers cP-1 and cP-2 shown in Tables 1 to 3 below were synthesized in the same manner as in Synthesis Example 1-1, except that the kind and blending ratio of each monomer were changed. In Tables 1 to 3 below, the introduction ratio represents the molar ratio.

[0479] [Table 1]

[0480]

[0481] [Table 2]

[0482]

[0483] [Table 3]

[0484]

[0485] The structure of the repeating unit introduced in the polymer is shown below.

[0486] [Chemical Formula 117]

[0487]

[0488] [Chemical Formula 118]

[0489]

[0490] [Chemical Formula 119]

[0491]

[0492] [Chemical Formula 120]

[0493]

[0494] [Chemical Formula 121]

[0495]

[0496] The dissolution rate of the aforementioned polymers to an alkali developer was determined as follows. After an 8-inch silicon wafer was spin-coated with a polymer solution (polymer concentration: 16.7 mass%, solvent: PGME) and baked at 100°C for 90 seconds to form a film having a thickness of 1,000 nm, the film was developed with a 2.38 mass% aqueous TMAH solution at 23°C for 100 seconds, and the amount of film loss was measured to calculate the dissolution rate. As a result, the dissolution rates of the polymers P-1 to P-44 and comparative polymer cP-2 were 10 nm / min or less, and the dissolution rate of comparative polymer cP-1 was 20 nm / min.

[0497] [Synthesis Examples 2-1 to 2-6, Comparative Synthesis Example 1-3] Synthesis of Polymers AP-1 to AP-6 and Polymer cP-3

[0498] Using the starting compounds shown below, polymers AP-1 to AP-6 and comparative polymer cP-3 were synthesized in the same manner as in Synthesis Example 1-1, except that the starting compounds were changed.

[0499] [Chemical 122]

[0500]

[0501] [Chemical 123]

[0502]

[0503] [Chemical 124]

[0504]

[0505] The dissolution rates of polymers AP-1 to AP-6 and comparative polymer cP-3 were 10 nm / min or less.

[0506] [2] Preparation of a chemically amplified positive resist composition

[0507] [Examples 1-1 to 1-58, Comparative Examples 1-1 to 1-5]

[0508] Each component was dissolved in an organic solvent in accordance with the composition shown in Tables 4 to 7 below, and the obtained solution was filtered with a UPE filter of 0.02 μm size to prepare a chemically amplified positive resist composition. Also, the aforementioned organic solvent was a mixed solvent of PGMEA 340 parts by mass, EL 1,700 parts by mass, and PGME 1,360 parts by mass.

[0509] [Table 4]

[0510]

[0511]

[0512] [Table 5]

[0513]

[0514] [Table 6]

[0515]

[0516] [Table 7]

[0517]

[0518] Also, in Tables 4 to 7, the structures of the quenchers Q-1 to Q-3, the photo acid generators PAG-A to PAG-C, and the polymers D-1 to D-5 are shown below.

[0519] [Chemical 125]

[0520]

[0521] [Chemical 126]

[0522]

[0523] [Chemical 127]

[0524]

[0525] [3] EB lithography evaluation

[0526] [Examples 2-1 to 2-57, Comparative Examples 2-1 to 2-4]

[0527] Each of the chemical amplification positive resist compositions (R-1 to R-57, CR-1 to CR-4) was spin-coated on a 152 mm square blank photomask having a chromium top surface using ACT-M (Tokyo Ohka Kogyo Co., Ltd.) on a hot plate at 110°C for 600 seconds prebake to form a resist film having a thickness of 80 nm. The film thickness of the obtained resist film was measured using an optical film thickness meter, NANOSPEC (NANOMETRICS Corporation). The measurement was performed at 81 points in the plane of the blank substrate excluding the outer edge portion from the outer periphery to 10 mm inside thereof, and the average film thickness and the film thickness range were calculated.

[0528] Further, exposure was performed using an electron beam exposure device (EBM-5000plus, Nuflare Technology, Inc., accelerating voltage 50 kV), 600 seconds PEB was performed at 110°C, and development was performed using a 2.38 mass% TMAH aqueous solution to obtain a positive pattern.

[0529] The obtained resist pattern was evaluated in the following manner. The blank mask on which the pattern was formed was observed with an SEM (scanning electron microscope), the exposure amount at which a 1 : 1 line and space (LS) of 200 nm was resolved at a 1 : 1 ratio was defined as the optimum exposure amount (pC / cm 2 ), the minimum size in the exposure amount at which a 1 : 1 line and space (LS) of 200 nm was resolved at a 1 : 1 ratio was defined as the resolution (limit resolution), and the edge roughness (LER) of a 200 nm LS was measured with an SEM. With respect to the development load evaluation, the exposure amount (pC / cm 2The pitch size of the 200 nm LS pattern formed and the 200 nm LS pattern of which the virtual pattern of 15%, 25%, 33%, 45%, 50%, 55%, 66%, 75%, 85%, 95% density is arranged around the periphery of the pattern was compared, and the difference in the size of the dense and sparse patterns was compared. As for the pattern shape, it was visually determined whether it was rectangular or not.

[0530] The dissolution rate of the overexposed portion was calculated from the thickness of the resist film after the resist solution was spin-coated on an 8-inch silicon wafer, baked at 110°C for 60 seconds to form a resist film having a thickness of 90 nm, and exposed at a line-and-space (LS) of 200 nm at a 1:1 resolution with an exposure amount (mJ / cm 2 After exposure with a KrF excimer laser and baking at 110°C for 60 seconds, the development was performed at 23°C using a 2.38 mass% TMAH aqueous solution using a resist development analyzer (RDA-800 manufactured by LITHO TECH JAPAN (K.K.)) to calculate the dissolution rate. The results are shown in Tables 8 to 10.

[0531] [Table 8]

[0532]

[0533] [Table 9]

[0534]

[0535] [Table 10]

[0536]

[0537] [4] Etch Resistance Evaluation

[0538] [Examples 3-1 to 3-3, Comparative Example 3-1]

[0539] Each of the chemically amplified positive resist compositions (R-9, R-22, R-58, CR-5) was spin-coated on a 152 mm square blank photomask having a chromium surface using ACT-M (manufactured by Tokyo Ohka Kogyo, K.K.) and prebaked at 110°C for 600 seconds on a hot plate to form a resist film having a thickness of 120 nm. The thickness of the obtained resist film was measured using an optical thickness meter, NANOSPEC (manufactured by NANOMETRICS). The measurement was performed at 81 points in the plane of the blank substrate except for the outer edge portion from the outer periphery to 10 mm inside thereof, and the average thickness and the thickness range were calculated. The obtained coated substrate was dry-etched using a dry etching device (UNAXIS G4) under the following conditions, and the film loss rate (A / sec) derived from the residual film after etching was calculated. The results are shown in Table 11.

[0540] RF1 (RIE): pulse 700 V

[0541] RF2(ICP): CW 400W

[0542] Pressure: 6 mTorr

[0543] Cl2: 185 seem

[0544] O2: 55 seem

[0545] He: 9.25 seem

[0546] Etching time: 75 sec

[0547] [Table 11]

[0548]

[0549] The chemical amplification positive resist compositions (R-1 to R-57) of the present application all showed good resolution, LER, and pattern rectangularity, and showed values in which development load was suppressed. On the other hand, in the resist compositions (CR-1 to CR-4) of the comparative examples, the unexposed portion dissolution rate of the polymer of CR-1 was high, the top portion became a circular shape, and the resolution deteriorated. CR-2 had a too small overexposed portion dissolution rate, so development load was not sufficiently suppressed, and CR-3 and CR-4 had insufficient design of the base polymer, so although development load was good, resolution, LER, and pattern rectangularity could not be balanced. It is believed that the design of the base polymer of the present application, specifically, that the PAG-attached polymer skeleton was not possessed, and a phenolic acid-labile group and an acrylate acid-labile group were combined, thereby successfully achieving optimization of the pattern shape using the phenolic unit and optimization of the overexposed portion dissolution rate using the acrylate, and resolution, LER, pattern rectangularity, and development load suppression were achieved. Also, in the dry etching evaluation using R-9, R-22, and R-58, etching resistance was better than that of CR-5, and it was suggested that when the base polymer contains 65 mol% or more of an aromatic ring skeleton, mask processing is effective.

[0550] The resist pattern forming method using the chemical amplification positive resist composition of the present application is useful in optical lithography in semiconductor device manufacturing, particularly in mask processing of transmissive and reflective blank masks.

Claims

1. A chemically amplified positive resist composition comprising a base polymer protected with an acid-labile group, which becomes alkali-soluble by action of an acid, the base polymer including a polymer containing a unit containing a phenolic hydroxyl group, a unit in which a phenolic hydroxyl group is protected with an acid-labile group, and a unit in which a carboxyl group is protected with an acid-labile group, or a polymer containing a unit containing a phenolic hydroxyl group and a unit in which a phenolic hydroxyl group is protected with an acid-labile group, and a polymer containing a unit containing a phenolic hydroxyl group and a unit in which a carboxyl group is protected with an acid-labile group, the polymer contained in the base polymer not containing a repeating unit that generates an acid by exposure, the unit containing a phenolic hydroxyl group being a repeating unit represented by the following formula (Al), the unit in which a phenolic hydroxyl group is protected with an acid-labile group being a repeating unit represented by the following formula (A2), and the unit in which a carboxyl group is protected with an acid-labile group being a repeating unit represented by the following formula (A3), of all the repeating units of the polymer contained in the base polymer, the repeating unit having an aromatic ring skeleton being 65 mol% or more, in the formula, a is an integer satisfying 0 < a < 5 + 2c - b, b is an integer of 1 to 3, and c is an integer of 0 to 2, R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, X 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * is an atomic bond between the carbon atom of the main chain, A 1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon numbers, a part of -CH2- constituting the saturated hydrocarbylene group can also be replaced by -O-, R 1 a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which can be substituted with a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which can be substituted with a halogen atom, or a saturated hydrocarbon oxy group having 1 to 6 carbon atoms which can be substituted with a halogen atom, In the formula, R A As mentioned previously, d is an integer satisfying 0 < d < 5 + 2f - e, e is an integer of 1 to 3, and f is an integer of 0 to 2, X 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * is an atomic bond between the carbon atom of the main chain and A 2 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon numbers, a part of -CH2- constituting the saturated hydrocarbylene group can also be replaced by -O-, R 2 a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbon atoms which can be substituted with a halogen atom, a saturated hydrocarbon group having 1 to 6 carbon atoms which can be substituted with a halogen atom, or a saturated hydrocarbon oxy group having 1 to 6 carbon atoms which can be substituted with a halogen atom, R 3 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 of them is an acid labile group, In the formula, R A As mentioned previously, X 3 is a single bond, phenylene, naphthylene or *-C(=O)-O-X 3A -, X 3A is a saturated hydrocarbylene group having a carbon number of 1 to 20 which can also contain a hydroxyl group, an ether bond, an ester bond or a lactone ring, or phenylene or naphthylene, * is an atomic bond between the carbon atom of the main chain, R 4 is an acid labile group.

2. The chemically amplified positive resist composition according to claim 1, wherein, the unit containing a phenolic hydroxyl group being a repeating unit represented by the following formula (Al-1), wherein R A and b are as previously described.

3. The chemically amplified positive resist composition according to claim 1 or 2, wherein, the unit in which a phenolic hydroxyl group is protected with an acid-labile group being a repeating unit represented by the following formula (A2-1), wherein R A As described above, R 5 is an acid-labile group having an aromatic hydrocarbon group having a carbon number of 6 to 20 and / or an alicyclic hydrocarbon group having a carbon number of 5 to 20.

4. The chemically amplified positive resist composition according to claim 1 or 2, wherein, the unit in which a carboxyl group is protected with an acid-labile group being a repeating unit represented by the following formula (A3-1), wherein R A and X 3 are the same as described above, R 6 is an acid-labile group having an aromatic hydrocarbon group having a carbon number of 6 to 20 and / or an alicyclic hydrocarbon group having a carbon number of 5 to 20.

5. The chemically amplified positive resist composition according to claim 1 or 2, wherein, the unit in which a carboxyl group is protected with an acid-labile group being a repeating unit represented by the following formula (A3-2), wherein R A and X 3 as described above, R B and R C each independently is a hydrocarbon group of 1 to 10 carbon numbers which can also contain heteroatoms, R B and R C may also be bonded to each other and, together with the carbon atom to which they are bonded, form a ring, R 7 each independently a fluorine atom, a fluorinated alkyl group having a carbon number of 1 to 5, or a fluorinated alkoxy group having a carbon number of 1 to 5, R 8 each independently is a hydrocarbon group having a carbon number of 1 to 10 which can also contain heteroatoms, n1 is 1 or 2, n2 is an integer of 0 to 5, and n3 is an integer of 0 to 2.

6. The chemically amplified positive resist composition according to claim 5, wherein, the repeating unit represented by the formula (A3-2) is represented by the following formula (A3-3), wherein R A , R B , R C , X 3 , R 7 , R 8 , n1 and n2 are as previously described.

7. The chemically amplified positive resist composition according to claim 5, wherein R 7 is a fluorine atom, a trifluoromethyl group or a trifluoromethoxy group.

8. The chemically amplified positive resist composition according to claim 1 or 2, wherein, the polymer contained in the base polymer further containing a repeating unit represented by any one of the following formulas (Bl) to (B3), In the formula, R A As mentioned previously, g and h are each independently an integer of 0 to 4, i is an integer of 0 to 5, and j is an integer of 0 to 2, R 11 and R 12 each independently is a hydroxyl group, a halogen atom, a saturated hydrocarbon carbonyloxy group having 2 to 8 carbons which can be substituted with a halogen atom, a saturated hydrocarbon group having 1 to 8 carbons which can be substituted with a halogen atom, or a saturated hydrocarbon oxy group having 1 to 8 carbons which can be substituted with a halogen atom, R 13 R1is hydrogen, a halogen atom, a nitro group, a cyano group, an acetyl group, a saturated hydrocarbon group having 1 to 20 carbon atoms, a saturated hydrocarbonoxy group having 1 to 20 carbon atoms, a saturated hydrocarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbonoxylalkyl group having 2 to 20 carbon atoms, a saturated hydrocarbonsulfinylalkyl group having 2 to 20 carbon atoms, a hydroxyl group when j is 1 or 2, X 4 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * is an atomic bond between the carbon atom of the main chain, A 3 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon number, and a part of -CH2- constituting the saturated hydrocarbylene group can also be replaced by -O-.

9. The chemically amplified positive resist composition according to claim 8, wherein, the total of the repeating unit represented by the formula (Al) and the repeating unit represented by any one of the formulas (Bl) to (B3) being 50 mol% or more of all the repeating units of the polymer contained in the base polymer.

10. The chemically amplified positive resist composition according to claim 1 or 2, further comprising a polymer containing a fluorine atom, the polymer containing at least one kind selected from the group consisting of a repeating unit represented by the following formula (Cl), a repeating unit represented by the following formula (C2), a repeating unit represented by the following formula (C3), and a repeating unit represented by the following formula (C4), wherein R D each independently is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group, R 101 , R 102 , R 104 and R 105 are each independently a hydrogen atom or a saturated hydrocarbon group having a carbon number of 1 to 10, R 103 , R 106 , R 107 and R 108 are each independently a hydrogen atom, a hydrocarbon group having a carbon number of 1 to 15, a fluorinated hydrocarbon group having a carbon number of 1 to 15 or an acid labile group, R 103 , R 106 , R 107 and R 108 are each independently a hydrocarbon group or a fluorinated hydrocarbon group, an ether bond or a carbonyl group can also be inserted between carbon-carbon bonds, m is an integer of 1 to 3, Z 1 R1is a hydrocarbon group having a carbon number of 1 to 20 or a fluorinated hydrocarbon group having a carbon number of 1 to 20.

11. The chemically amplified positive resist composition according to claim 10, the polymer containing a fluorine atom further containing at least one kind selected from the group consisting of a repeating unit represented by the following formula (C5) and a repeating unit represented by the following formula (C6), wherein R E each independently is a hydrogen atom or a methyl group, R 109 a straight-chain or branched hydrocarbon group having 1 to 5 carbon atoms into which a heteroatom-containing group can also be inserted, R 110 linear or branched hydrocarbon group having 1 to 5 carbons into which a heteroatom-containing group has been inserted, R 111 a saturated hydrocarbon group having 1 to 20 carbon atoms of which at least one hydrogen atom is replaced with a fluorine atom, a part of -CH2- constituting the saturated hydrocarbon group can also be replaced with an ester bond or an ether bond, x is an integer of 1 to 3, y is an integer satisfying 0 < y < 5 + 2z - x, and z is 0 or 1, Z 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, * is an atomic bond between the carbon atom of the main chain, Z 3 is a single bond, -O-, -C(=O)-O-Z 31 -Z 32 - or -C(=O)-NH-Z 31 -Z 32 -, Z 31 is a single bond or a saturated hydrocarbylene group having a carbon number of 1 to 10, Z 32 is a single bond, an ester bond, an ether bond or a sulfonamide bond, and * is an atomic bond between a carbon atom of the main chain.

12. The chemically amplified positive resist composition according to claim 1 or 2, further comprising an organic solvent.

13. The chemically amplified positive resist composition according to claim 1 or 2, further comprising a photo-acid generator.

14. The chemically amplified positive resist composition according to claim 13, wherein, The acid strength (pKa) of the anion of the photo-acid generator is -2.0 or more.

15. The chemically amplified positive resist composition according to claim 1 or 2, 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.

16. A resist pattern forming method comprising the steps of: forming a resist film on a substrate using the chemically amplified positive resist composition according to any one of claims 1 to 15; irradiating a pattern to the resist film using a high-energy ray; and developing the resist film of the irradiated pattern using an alkali developer.

17. The resist pattern forming method according to claim 16, wherein The high-energy ray is an extreme ultraviolet ray or an electron beam.

18. The resist pattern forming method according to claim 16 or 17, wherein, The topmost surface of the substrate is composed of a material containing at least one selected from the group consisting of chromium, silicon, tantalum, molybdenum, cobalt, nickel, tungsten, and tin.

19. The resist pattern forming process according to claim 16 or 17, wherein, The substrate is a blank photomask.

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

Images