Monomer, polymer, chemically amplified negative resist composition, and resist pattern forming method

Abstract

To provide a chemically amplified negative resist composition which improves resolution during pattern formation and can give a resist pattern improved in LER, pattern fidelity, and dose margin, and to provide a resist pattern forming method.SOLUTION: There are provided a monomer represented by the following formula (A1), a polymer containing a repeating unit derived from the monomer, and a chemically amplified negative resist composition containing a base polymer containing the polymer.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a monomer, a polymer, a chemically amplified negative resist composition, and a method of forming a resist pattern. [Background technology]

[0002] In recent years, pattern rules have become finer with the increasing integration and speed of LSI. Chemically amplified resist compositions using acids as catalysts are used exclusively for processing patterns of 0.2 μm or less. High-energy rays such as ultraviolet rays, far ultraviolet rays, and electron beams (EB) are used as exposure sources. In particular, EB lithography, which is used as an ultrafine processing technology, is also indispensable as a processing method for photomask blanks when producing photomasks for semiconductor manufacturing.

[0003] Polymers having a large amount of aromatic skeletons with acidic side chains, such as polyhydroxystyrene, are useful as materials for resist compositions for KrF lithography using KrF excimer lasers, but have not been used as materials for resist compositions for ArF lithography using ArF excimer lasers because they exhibit high absorption for light with wavelengths of around 200 nm. However, they are important materials for resist compositions for EB lithography, which is a powerful technique for forming patterns smaller than the processing limit of ArF excimer lasers, and resist compositions for extreme ultraviolet (EUV) lithography, because they provide high etching resistance.

[0004] Resist compositions used in photolithography include positive types that dissolve exposed areas to form a pattern, and negative types that leave exposed areas to form a pattern, and the one that is easier to use is selected depending on the type of resist pattern required. Chemically amplified negative resist compositions usually contain a polymer that dissolves in an aqueous alkaline developer, an acid generator that decomposes with exposure light to generate acid, and a crosslinking agent that uses acid as a catalyst to form crosslinks between the polymers to make the polymer insoluble in the developer (in some cases, the polymer and the crosslinking agent are integrated), and further usually contain a quencher to control the diffusion of the acid generated by exposure.

[0005] Examples of the alkali-soluble units constituting the polymer that dissolves in the aqueous alkaline developer include units derived from phenols. Conventionally, many negative resist compositions of this type have been developed, particularly for exposure with KrF excimer laser light. However, these have not been used for ArF excimer laser light because the units derived from phenols do not have light transmittance when the exposure light has a wavelength of 150 to 220 nm. However, in recent years, they have been attracting attention again as negative resist compositions for short-wavelength exposure light such as EB and EUV, which are exposure methods for obtaining finer patterns, and for example, Patent Documents 1, 2 and 3 have been reported.

[0006] In addition to the above, many materials have been developed as materials for chemically amplified negative resist compositions. For example, crosslinking agents as described in Patent Documents 4 and 5 are used as agents for insolubilizing an alkali-soluble polymer that provides a negative mechanism used in a resist composition by the action of an acid generated when the polymer is irradiated with high energy rays, and many crosslinking agents have been developed. On the other hand, many attempts have been made to impart the function of this crosslinking agent to a polymer, and methods such as a method of introducing a styrene unit substituted with an alkoxymethoxy group (Patent Document 6), a method of introducing a repeating unit having an alkoxymethylamino group (Patent Document 7), a method of introducing a repeating unit having an epoxy group (Patent Document 8), a method of introducing a styrene-based repeating unit having an acid-leaving group (Patent Document 9), a method of introducing an adamantyl-based repeating unit having an acid-leaving hydroxyl group (Patent Document 10), and a method of introducing an aliphatic hydrocarbon group and an alicyclic hydrocarbon-based repeating unit having an acid-leaving hydroxyl group (Patent Documents 9 to 15) have been proposed.

[0007] Although these methods have been confirmed to improve performance to a certain extent, satisfactory results have not yet been obtained. In order to meet the demand for further miniaturization, it is important to develop chemically amplified negative resist materials that are excellent in sensitivity, limit resolution, and high contrast. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 4396849 [Patent Document 2] Patent No. 4478589 [Patent Document 3] Patent No. 4678383 [Patent Document 4] Patent No. 4955732 [Patent Document 5] Patent No. 4801190 [Patent Document 6] Japanese Patent Application Publication No. 5-232702 [Patent Document 7] Japanese Patent Application Publication No. 8-202037 [Patent Document 8] Patent No. 3914363 [Patent Document 9] JP 2003-337414 A [Patent Document 10] Patent No. 4648526 [Patent Document 11] U.S. Patent No. 7,300,739 [Patent Document 12] U.S. Patent No. 7,393,624 [Patent Document 13] U.S. Patent No. 7,563,558 [Patent Document 14] JP 2013-164588 A [Patent Document 15] JP 2019-203103 A Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a chemically amplified negative resist composition that improves the resolution during pattern formation and that is capable of obtaining a resist pattern with improved LER, pattern fidelity, and dose margin, and a method of forming a resist pattern. [Means for solving the problem]

[0010] As a result of intensive research into achieving the above-mentioned object, the present inventors have found that when a polymer including a repeating unit derived from a monomer having a specific dehydrating functional group is introduced into a chemically amplified negative resist composition, good resolution and pattern shape are exhibited, and the LER, pattern fidelity and dose margin are improved, and a pattern having excellent etching resistance can be obtained, which has led to the completion of the present invention.

[0011] That is, the present invention provides the following monomer, polymer, chemically amplified negative resist composition, and method of forming a resist pattern. 1. A monomer represented by the following formula (A1): [ka] (In the formula, a1 is 1 or 2. a2 is 0, 1 or 2. R A each independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 1 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. R 2 and R 3 are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms, or an aryl group having 6 to 15 carbon atoms, the hydrocarbyl group may be substituted with a hydroxy group or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, and the aryl group may have a substituent. 2 and R 3 cannot be a hydrogen atom at the same time. 2 and R 3 may be bonded to each other to form a ring together with the carbon atom to which they are bonded, and a portion of -CH2- in the ring may be substituted with -O- or -S-. W 1 represents a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, an aliphatic hydrocarbylcarbonyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 15 carbon atoms, and the aryl group may have a substituent. 2. A monomer 1 represented by the following formula (A1-1): [ka] (In the formula, a2, R A , R 1 , R 2 , R 3 and W 1 is the same as above.) 3. A monomer 2 represented by the following formula (A1-2): [ka] (In the formula, a2, R A , R 1 , R 2 and R 3 is the same as above.) 4. A polymer containing a repeating unit derived from any one of the monomers 1 to 3. 5. The polymer of 4 further comprising a repeating unit represented by the following formula (A2): [ka] (In the formula, b1 is 0 or 1. b2 is 0, 1 or 2. b3 is an integer satisfying 0≦b3≦5+2(b2)−b4. b4 is 1, 2 or 3. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 11 represents a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. A 1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of -CH2- in the saturated hydrocarbylene group may be substituted with -O-. 6. The polymer of 4 or 5 further comprising at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (A3), a repeating unit represented by the following formula (A4) and a repeating unit represented by the following formula (A5). [ka] (In the formula, c and d each independently represent an integer of 0 to 4. e1 is 0 or 1. e2 is 0, 1 or 2. e3 is an integer of 0 to 5. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R21 and R 22 each independently represents a hydroxy group, a halogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. R 23 represents a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms, a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group, a cyano group, a saturated hydrocarbylsulfinyl group having 1 to 20 carbon atoms, or a saturated hydrocarbylsulfonyl group having 1 to 20 carbon atoms. A 2 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of -CH2- in the saturated hydrocarbylene group may be substituted with -O-. 7. The polymer according to any one of 4 to 6, further comprising a repeating unit represented by the following formula (A6): [ka] (In the formula, f1 is 0 or 1. f2 is 0, 1, or 2. f3 is an integer satisfying 0≦f3≦5+2(f2)−f4. f4 is 1, 2, or 3. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 31 represents a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. R 32 and R 33are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms, or an aryl group having 6 to 15 carbon atoms, the hydrocarbyl group may be substituted with a hydroxy group or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, and the aryl group may have a substituent. 32 and R 33 cannot be a hydrogen atom at the same time. 32 and R 33 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. A 3 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and -CH2- of the saturated hydrocarbylene group may be substituted with -O-. W 2 represents a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, an aliphatic hydrocarbylcarbonyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 15 carbon atoms, and the aryl group may have a substituent. 8. A polymer according to any one of 4 to 7, further comprising at least one repeating unit selected from those represented by the following formulae (A7) to (A14): [ka] (In the formula, R B are each independently a hydrogen atom or a methyl group. X 1 each independently represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these groups; -OX 11 -, -C(=O)-OX 11 - or -C(=O)-NH-X 11 - and X 11 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group obtained by combining these and having 7 to 18 carbon atoms, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. X 2 each independently represents a single bond or -X 21 -C(=O)-O-, X21 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. X 3 each independently represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -OX 31 -, -C(=O)-OX 31 - or -C(=O)-NH-X 31 - and X 31 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. X 4 each independently represents a single bond or a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. g1 and g2 are each independently 0 or 1, 4 When is a single bond, g1 and g2 are 0. R 41 ~R 58 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 41 and R 42 may be bonded to each other to form a ring together with the sulfur atom to which they are attached, R 43 and R 44 , R 46 and R 47 , or R 49 and R 50 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. R HF is a hydrogen atom or a trifluoromethyl group. Xa - is a non-nucleophilic counterion. 9. A chemically amplified negative resist composition comprising a base polymer containing any one of the polymers 4 to 8. 10. The chemically amplified negative resist composition of 9, wherein the content of repeating units having an aromatic ring skeleton among all repeating units of the polymer contained in the base polymer is 60 mol % or more. 11. The chemically amplified negative resist composition of 9 or 10, further comprising (B) an acid generator. 12. Any one of the chemically amplified negative resist compositions 9 to 11, further comprising (C) a crosslinking agent. 13. Any one of the chemically amplified negative resist compositions 9 to 11, which does not contain a crosslinking agent. 14. Any of the chemically amplified negative resist compositions 9 to 13, further comprising (D) a fluorine atom-containing polymer which contains at least one selected from the group consisting of a repeating unit represented by the following formula (D1), a repeating unit represented by the following formula (D2), a repeating unit represented by the following formula (D3), and a repeating unit represented by the following formula (D4), and which may further contain at least one selected from the group consisting of a repeating unit represented by the following formula (D5) and a repeating unit represented by the following formula (D6). [ka] (In the formula, x is 1, 2, or 3. y is an integer satisfying 0≦y≦5+2z−x. z is 0 or 1. k is 1, 2, or 3. R C each independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R D are each independently a hydrogen atom or a methyl group. R 101 , R 102 , R 104 and R 105 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. R 103 , R 106 , R 107 and R 108 each independently represents a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or an acid labile group; R 103 , R 106 , R 107 and R108 When is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be present between the carbon-carbon bonds. R 109 represents a hydrogen atom or a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a group containing a heteroatom interposed between the carbon-carbon bonds. R 110 is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a group containing a heteroatom interposed between the carbon-carbon bonds. R 111 represents a saturated hydrocarbyl group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, and a portion of the -CH2- in the saturated hydrocarbyl group may be substituted with an ester bond or an ether bond. Z 1 is a (k+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (k+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. Z 2 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. Z 3 is a single bond, -O-, *-C(=O)-OZ 31 -Z 32 - or -C(=O)-NH-Z 31 -Z 32 -It is. 31 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. 32 is a single bond, an ester bond, an ether bond or a sulfonamide bond. * is a bond to a carbon atom in the main chain.) 15. The negative resist composition according to any one of 9 to 14, further comprising (E) a quencher. 16. Any one of the chemically amplified negative resist compositions 9 to 15, further comprising (F) an organic solvent. 17. A method for forming a resist pattern, comprising the steps of: forming a resist film on a substrate using the chemically amplified negative resist composition according to any one of claims 9 to 16; irradiating the resist film with a pattern using high-energy rays; and developing the resist film irradiated with the pattern using an alkaline developer. 18. The method for forming a resist pattern according to claim 17, wherein the high energy radiation is EUV or EB. 19. The method for forming a resist pattern according to claim 17 or 18, wherein the outermost surface of the substrate is made of a material containing at least one selected from the group consisting of chromium, silicon, tantalum, molybdenum, cobalt, nickel, tungsten and tin. 20. The method for forming a resist pattern according to any one of 17 to 19, wherein the substrate is a transmission type or a reflection type mask blank. 21. A transmission or reflection mask blank coated with any one of the chemically amplified negative resist compositions 9 to 16. Effect of the Invention

[0012] When a pattern is formed using a chemically amplified negative resist composition containing as a base polymer a polymer obtained from the monomer of the present invention, a polarity change accompanied by a dehydration reaction proceeds with good sensitivity, and a pattern having high resolution and pattern fidelity, improved LER and dose margin, and excellent etching resistance can be formed. Therefore, the composition can be suitably used in microfabrication techniques, in particular EUV lithography and EB lithography. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present invention will be described in detail below, but the present invention is not limited thereto. In the following description, some structures represented by chemical formulas may have asymmetric carbons and may have enantiomers or diastereomers, and in such cases, one formula will be used to represent these isomers. These isomers may be used alone or as a mixture.

[0014] [monomer] The monomer of the present invention is represented by the following formula (A1). [ka]

[0015] In formula (A1), a1 is an integer of 1 or 2, and is preferably 1. a2 is an integer of 0, 1 or 2, and is preferably 0 or 1.

[0016] In formula (A1), R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Among these, a hydrogen atom or a methyl group is preferable.

[0017] In formula (A1), R 1 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom.

[0018] R 1 Specific examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0019] R 1 The hydrocarbyl group having 1 to 20 carbon atoms represented by the formula (I) may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a tert-pentyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, and an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, a tricyclo[5.2.1.0 2,6] cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as decyl group, adamantyl group, and adamantylmethyl group; aryl groups having 6 to 20 carbon atoms, such as phenyl group, naphthyl group, and anthryl group; and groups obtained by combining these. In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom, such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a 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 bond, a carbamate bond, an amide bond, an imide bond, a lactone ring, a sultone ring, a thiolactone ring, a lactam ring, a sultam ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0020] In formula (A1), R 2 and R 3 each independently represents a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms, or an aryl group having 6 to 15 carbon atoms, the hydrocarbyl group optionally being substituted with a hydroxy group or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, and the aryl group optionally having a substituent.

[0021] R 2 and R 3 The saturated hydrocarbyl group having 1 to 15 carbon atoms represented by the formula (I) may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 15 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, an n-hexyl group, a 2-ethylhexyl group, an n-octyl group, an n-nonyl group or an n-decyl group; and cyclic saturated hydrocarbyl groups having 3 to 15 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 or an adamantyl group.

[0022] R 2 and R 3 Specific examples of the aryl group having 6 to 15 carbon atoms represented by the formula (1) include a phenyl group, a naphthyl group, and an anthryl group, among which a phenyl group is preferred. The aryl group may have a substituent, and specific examples of the substituent include a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, and a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom.

[0023] Also, R 2 and R 3 cannot simultaneously be a hydrogen atom. 2 and R 3 When either of the groups is an optionally substituted aryl group, the other substituent is preferably a hydrogen atom.

[0024] R 2 and R 3 are preferably the same group, and more preferably both are methyl groups.

[0025] Also, R 2 and R 3 may be bonded to each other to form a ring together with the carbon atom to which they are bonded, and a part of -CH2- in the ring may be replaced by -O- or -S-. Examples of the ring include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, an adamantane ring, a tricyclo[5.2.1.0 2,6 ] Decane ring, tetracyclo[6.2.1.1 3,6 .0 2,7 ]dodecane ring, oxanorbornane ring, thianorbornane ring and the like, but are not limited to these.

[0026] In formula (A1), W 1represents a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, an aliphatic hydrocarbylcarbonyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 15 carbon atoms, and the aryl group may have a substituent.

[0027] W 1 The aliphatic hydrocarbyl group having 1 to 10 carbon atoms represented by the formula (1) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms, such as cyclopentyl and cyclohexyl; alkenyl groups having 2 to 10 carbon atoms, such as vinyl, 1-propenyl, 2-propenyl, butenyl, and hexenyl; and cyclic unsaturated hydrocarbyl groups having 3 to 10 carbon atoms, such as cyclohexenyl. W 1 The hydrocarbyl portion of the aliphatic hydrocarbyl carbonyl group having 2 to 10 carbon atoms represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include those having 1 to 9 carbon atoms among the specific examples of the aliphatic hydrocarbyl group having 1 to 10 carbon atoms described above. W 1 Specific examples of the aryl group having 6 to 15 carbon atoms represented by the formula (1) include a phenyl group, a naphthyl group, and an anthryl group, among which a phenyl group is preferred. The aryl group may have a substituent, and specific examples of the substituent include a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, and a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom.

[0028] W 1 is preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, still more preferably a hydrogen atom or a methyl group, and most preferably a hydrogen atom.

[0029] The monomer represented by formula (A1) is preferably one represented by the following formula (A1-1). [ka] (In the formula, a2, R A , R 1 , R 2 , R 3 and W 1 is the same as above.)

[0030] The monomer represented by formula (A1-1) is further preferably one represented by the following formula (A1-2). [ka] (In the formula, a2, R A , R 1 , R 2 and R 3 is the same as above.)

[0031] Specific examples of the monomer represented by formula (A1) include, but are not limited to, those shown below. In the following formula, R A is the same as above, Me is a methyl group, and Ac is an acetyl group. [ka]

[0032] [ka]

[0033] [ka]

[0034] [ka]

[0035] [ka]

[0036]

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[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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[0045]

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[0046]

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[0048]

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[0049]

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[0050]

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[0051]

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[0052]

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[0053]

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[0055]

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[0057] [ka]

[0058] [ka]

[0059] [ka]

[0060] [ka]

[0061] [ka]

[0062] [ka]

[0063] [ka]

[0064] The monomer of the present invention can be synthesized by a known method. For example, in the above formula (A1), R 2 and R 3 are the same group, and W 1 Although a monomer A1-ex in which is a hydrogen atom will be described, the synthesis method is not limited thereto. [ka] (In the formula, a2, R A , R 1 and R 2 is the same as above. R x is a hydrocarbyl group having 1 to 10 carbon atoms.hal is a chlorine atom, a bromine atom, or an iodine atom.

[0065] In the method, a Grignard reagent is reacted with an ester compound SM-1 or a ketone compound SM-2, which are commercially available or can be synthesized by a known synthesis method, to obtain the target monomer A1-ex.

[0066] The reaction can be carried out by a known organic synthesis method. Specifically, metallic magnesium is suspended in an ether solvent such as tetrahydrofuran (THF) or diethyl ether, and a halide diluted with the solvent used is dropped to prepare a Grignard reagent. When preparing a Grignard reagent, particularly when the halide is a chloride, the reaction can be efficiently started by adding a small amount of 1,2-dibromoethane or a small amount of iodine before starting the dropwise addition of the halide. An ester compound SM-1 or a ketone compound SM-2 diluted with the solvent used is dropped to the prepared Grignard reagent. The reaction temperature is from room temperature to the boiling point of the solvent used. The reaction time is usually about 30 minutes to 2 hours, although it is desirable to follow the reaction by gas chromatography (GC) or silica gel thin layer chromatography (TLC) to complete the reaction in terms of yield. The target monomer A1-ex can be obtained from the reaction mixture by a normal aqueous work-up. The resulting monomer A1-ex can be purified, if necessary, by a conventional method such as distillation, chromatography, or recrystallization.

[0067] The structural feature of the monomer of the present invention is that it has an acenaphthylene structure as a polymerizable group and has an acid dehydrating group (or acid leaving group) bonded thereto. The acid dehydrating group (acid leaving group) reacts with the acid generated from the acid generator to cause a dehydration reaction (elimination reaction) and generate a benzyl cation. The nearby hydrogen atom is released as a proton, resulting in an olefin structure conjugated with the acenaphthylene structure, which becomes hydrophobic. Alternatively, the hydrophobicity is improved by the nucleophilic attack of the phenolic hydroxy group in the copolymerized polymer chain on the generated benzyl cation. In addition, the acenaphthylene structure is a rigid structure, and exhibits good resistance in the etching process after the formation of the resist pattern. Due to these synergistic effects, the chemically amplified negative resist composition containing the polymer using the monomer of the present invention as a copolymerization unit has good contrast and resolution between exposed and unexposed areas, and can form a resist pattern with excellent developer resistance and etching resistance even in the formation of a fine pattern.

[0068] [polymer] The polymer of the present invention contains a repeating unit derived from the above-mentioned monomer (hereinafter referred to as repeating unit A1).

[0069] The polymer may further include a repeating unit represented by the following formula (A2) (hereinafter, also referred to as repeating unit A2): Repeating unit A2 is a repeating unit that imparts etching resistance, adhesion to a substrate, and solubility in an alkaline developer. [ka]

[0070] In formula (A2), b1 is 0 or 1. b2 is 0, 1 or 2, and when it is 0, it represents a benzene skeleton, when it is 1, it represents a naphthalene skeleton, and when it is 2, it represents an anthracene skeleton. b3 is an integer that satisfies 0≦b3≦5+2(b2)-b4. b4 is 1, 2 or 3. When b2 is 0, b3 is preferably an integer of 0 to 3, and b4 is 1, 2 or 3, and when b2 is 1 or 2, b3 is preferably an integer of 0 to 4, and b4 is 1, 2 or 3.

[0071] In formula (A2), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0072] In formula (A2), R 11 is a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. The saturated hydrocarbyl group, and the saturated hydrocarbyl part of the saturated hydrocarbyloxy group and the saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic, and specific examples thereof include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, butyl, pentyl, hexyl, and structural isomers thereof; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; and groups obtained by combining these groups. When the number of carbon atoms is equal to or less than the upper limit, the solubility in an alkaline developer is good. When b3 is 2 or more, each R 11 may be the same as or different from each other.

[0073] In formula (A2), A 1is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of -CH2- of the saturated hydrocarbylene group may be substituted with -O-. The saturated hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl groups having 1 to 10 carbon atoms, such as methylene, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, and structural isomers thereof; cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms, such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl; and groups obtained by combining these. When the saturated hydrocarbylene group contains an ether bond, when b1 in formula (A2) is 1, it may be located at any position except between the carbon atom at the α position and the carbon atom at the β position relative to the ester oxygen atom. When b1 is 0, the atom bonded to the main chain is an ether oxygen atom, and the second ether bond may be inserted at any position except between the carbon atom at the α-position and the carbon atom at the β-position with respect to the ether oxygen atom. If the number of carbon atoms in the saturated hydrocarbylene group is 10 or less, sufficient solubility in an alkaline developer can be obtained, which is preferable.

[0074] b1 is 0 and A 1 is a single bond, i.e., the aromatic ring is directly attached to the polymer backbone (i.e., the linker (-C(=O)-OA 1 In the case where the repeating unit A2 does not have -), preferred examples of the repeating unit A2 include units derived from 3-hydroxystyrene, 4-hydroxystyrene, 5-hydroxy-2-vinylnaphthalene, 6-hydroxy-2-vinylnaphthalene, etc. In particular, the repeating unit represented by the following formula (A2-1) is preferred. [ka] (In the formula, R A and b4 are the same as above.)

[0075] Also, b1 is 1 (i.e., -C(=O)-OA as a linker). 1-), preferred examples of the repeating unit A2 include, but are not limited to, those shown below. [ka] (In the formula, R A is the same as above.)

[0076] The repeating unit A2 may be used alone or in combination of two or more kinds.

[0077] For the purpose of improving etching resistance, the polymer may contain at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (A3) (hereinafter also referred to as repeating unit A3), a repeating unit represented by the following formula (A4) (hereinafter also referred to as repeating unit A4), and a repeating unit represented by the following formula (A5) (hereinafter also referred to as repeating unit A5). [ka]

[0078] In the formulae (A3) and (A4), c and d each independently represent an integer of 0 to 4.

[0079] In formulas (A3) and (A4), R 21 and R 22 are each independently a hydroxy group, a halogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic. When c is 2 or more, each R 21 may be the same or different. When d is 2 or more, each R 22 may be the same as or different from each other.

[0080] In formula (A5), e1 is 0 or 1. e2 is 0, 1, or 2, and when e2 is 0, it represents a benzene skeleton, when it is 1, it represents a naphthalene skeleton, and when it is 2, it represents an anthracene skeleton. e3 is an integer of 0 to 5. When e2 is 0, e3 is preferably an integer of 0 to 3, and when e2 is 1 or 2, e3 is preferably an integer of 0 to 4.

[0081] In formula (A5), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0082] In formula (A5), R 23 is a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms, a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group, a cyano group, a saturated hydrocarbylsulfinyl group having 1 to 20 carbon atoms, or a saturated hydrocarbylsulfonyl group having 1 to 20 carbon atoms. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, saturated hydrocarbyloxyhydrocarbyl group, saturated hydrocarbylthiohydrocarbyl group, saturated hydrocarbylsulfinyl group, and saturated hydrocarbylsulfonyl group may be linear, branched, or cyclic. When e3 is 2 or more, each R 23 may be the same as or different from each other.

[0083] R 23 Preferred are halogen atoms such as chlorine, bromine and iodine atoms, saturated hydrocarbyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclopentyl and cyclohexyl groups, and structural isomers thereof, and saturated hydrocarbyloxy groups such as methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, cyclopentyloxy, cyclohexyloxy, and structural isomers of the hydrocarbon moiety thereof. Of these, methoxy and ethoxy groups are particularly useful.

[0084] In addition, the saturated hydrocarbyl carbonyloxy group can be easily introduced by chemical modification even after polymerization of the polymer, and can be used to finely adjust the solubility of the base polymer in an alkaline developer. Examples of the saturated hydrocarbyl carbonyloxy group include methyl carbonyloxy group, ethyl carbonyloxy group, propyl carbonyloxy group, butyl carbonyloxy group, pentyl carbonyloxy group, hexyl carbonyloxy group, cyclopentyl carbonyloxy group, cyclohexyl carbonyloxy group, benzoyloxy group, and structural isomers of these hydrocarbon moieties. If the carbon number is 20 or less, the effect of controlling and adjusting (mainly the effect of reducing) the solubility of the base polymer in an alkaline developer can be made appropriate, and the occurrence of scum (development defects) can be suppressed.

[0085] Among the above-mentioned preferable substituents, examples of the substituents which are particularly easy to prepare as a monomer and are usefully used include a chlorine atom, a bromine atom, an iodine atom, a methyl group, an ethyl group, and a methoxy group.

[0086] In formula (A5), A 2is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of -CH2- of the saturated hydrocarbylene group may be replaced by -O-. The saturated hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl groups having 1 to 10 carbon atoms, such as methylene, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, and structural isomers thereof; cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms, such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl; and groups obtained by combining these. When the saturated hydrocarbylene group contains an ether bond, when e1 in formula (A5) is 1, it may be located at any position except between the carbon atom at the α position and the carbon atom at the β position relative to the ester oxygen atom. When e1 is 0, the atom bonded to the main chain is an etheric oxygen atom, and the second ether bond may be inserted at any position except between the carbon atom at the α-position and the carbon atom at the β-position relative to the etheric oxygen atom. If the number of carbon atoms in the saturated hydrocarbylene group is 10 or less, sufficient solubility in an alkaline developer can be obtained, which is preferable.

[0087] e1 is 0 and A 2 is a single bond, that is, the aromatic ring is directly attached to the polymer backbone (i.e., the linker (-C(=O)-OA 3 In the case where the repeating unit A5 does not have -), preferred examples of the repeating unit A5 include units derived from styrene, 4-chlorostyrene, 4-methylstyrene, 4-methoxystyrene, 4-bromostyrene, 4-acetoxystyrene, 2-hydroxypropylstyrene, 2-vinylnaphthalene, 3-vinylnaphthalene, etc.

[0088] Also, when e1 is 1 (i.e., -C(=O)-OA as a linker 2 Preferred examples of the repeating unit A5, when R A is the same as above. [ka]

[0089] [ka]

[0090] When at least one of the repeating units A3 to A5 is used as a structural unit of the polymer, the addition of a ring structure to the main chain provides an effect of improving the etching resistance of the aromatic ring as well as the EB irradiation resistance during pattern inspection.

[0091] The repeating units A3 to A5 may be used alone or in combination of two or more.

[0092] The polymer may further include a repeating unit represented by the following formula (A6) (hereinafter also referred to as repeating unit A6). [ka]

[0093] When the repeating unit A6 is irradiated with high energy rays, it converts to -OW by the action of the acid generated by the acid generator, like the repeating unit A1. 1 This repeating unit induces an elimination reaction, which makes the compound insoluble in an alkaline developer and induces a crosslinking reaction between polymers. The action of the repeating unit A6 can efficiently control the negative reaction, which can improve the resolution.

[0094] In formula (A6), f1 is 0 or 1. f2 is 0, 1, or 2. f3 is an integer satisfying 0≦f3≦5+2(f2)−f4. f4 is 1, 2, or 3.

[0095] In formula (A6), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0096] In formula (A6), R 31 is a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. The saturated hydrocarbyl group and the saturated hydrocarbyloxy group and the saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic, and specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, and structural isomers thereof; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; and groups obtained by combining these groups. When f3 is 2 or more, each R 31 may be the same as or different from each other.

[0097] In formula (A6), R 32 and R 33 are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms, or an aryl group having 6 to 15 carbon atoms, the hydrocarbyl group may be substituted with a hydroxy group or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, and the aryl group may have a substituent. 32 and R 33 cannot be a hydrogen atom at the same time. 32 and R 33 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. 13 and R 14 Preferred examples of the alkyl group include methyl, ethyl, propyl, butyl, and structural isomers of these alkyl groups, as well as those in which some of the hydrogen atoms have been substituted with hydroxy groups or saturated hydrocarbyloxy groups.

[0098] In formula (A6), A 3is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and -CH2- of the saturated hydrocarbylene group may be replaced by -O-. The saturated hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl groups such as methylene, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, and structural isomers thereof; cyclic saturated hydrocarbylene groups such as cyclopropanediyl, cyclobutanediyl, cyclopentanediyl, and cyclohexanediyl; and groups obtained by combining these. When the saturated hydrocarbylene group contains an ether bond, when f1 in formula (A6) is 1, it may be located at any position except between the carbon atom at the α position and the carbon atom at the β position relative to the ester oxygen atom. When f1 is 0, the atom bonding to the main chain is an ether oxygen atom, and a second ether bond may be inserted at any position except between the carbon atom at the α-position and the carbon atom at the β-position to the ether oxygen atom.

[0099] In formula (A6), W 2 is a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, an aliphatic hydrocarbylcarbonyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 15 carbon atoms, and the aryl group may have a substituent. 2 Specific examples of the group represented by the formula (A1) include W 1 Specific examples of the group represented by the formula:

[0100] The repeating unit A6 is preferably one represented by the following formula (A6-1) or (A6-2). [ka] (In the formula, f4, R A , R 32 and R 33 is the same as above.)

[0101] Preferred examples of the repeating unit A6 include, but are not limited to, those shown below. A is the same as above, Me is a methyl group, Et is an ethyl group, and Ac is an acetyl group. In addition, the group extending from the aromatic ring may be bonded to any position of the carbon atom forming the aromatic ring. [ka]

[0102] [ka]

[0103] [ka]

[0104] [ka]

[0105] [ka]

[0106] The repeating unit A6 may be used alone or in combination of two or more kinds.

[0107] The polymer may further include at least one selected from the repeating unit represented by the following formula (A7) (hereinafter also referred to as repeating unit A7), the repeating unit represented by the following formula (A8) (hereinafter also referred to as repeating unit A8), the repeating unit represented by the following formula (A9) (hereinafter also referred to as repeating unit A9), the repeating unit represented by the following formula (A10) (hereinafter also referred to as repeating unit A10), the repeating unit represented by the following formula (A11) (hereinafter also referred to as repeating unit A11), the repeating unit represented by the following formula (A12) (hereinafter also referred to as repeating unit A12), the repeating unit represented by the following formula (A13) (hereinafter also referred to as repeating unit A13), and the repeating unit represented by the following formula (A14) (hereinafter also referred to as repeating unit A14). In this case, acid diffusion can be effectively suppressed, and a pattern with improved resolution and reduced LER can be obtained. [ka]

[0108] In formulas (A7) to (A14), R B are each independently a hydrogen atom or a methyl group. 1 each independently represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these groups; -OX 11 -, -C(=O)-OX 11 - or -C(=O)-NH-X 11 - and X 11 X is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. 2 each independently represents a single bond or -X 21 -C(=O)-O-, X 21 X is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 3each independently represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -OX 31 -, -C(=O)-OX 31 - or -C(=O)-NH-X 31 - and X 31 X is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 4 Each of g1 and g2 is independently 0 or 1, but X 4 When is a single bond, g1 and g2 are 0.

[0109] In formulae (A7) and (A11), Xa - is a non-nucleophilic counterion. - Examples of non-nucleophilic counter ions represented by the formula (I) include those described in JP-A-2010-113209 and JP-A-2007-145797.

[0110] In formulas (A8) and (A12), X 2 -X 21 -C(=O)-O-, X 21 Examples of the hydrocarbylene group which may contain a heteroatom and is represented by the following formula (I) include, but are not limited to, the following groups: [ka] (In the formula, the dashed lines represent bonds.)

[0111] In formulas (A8) and (A12), R HF is a hydrogen atom or a trifluoromethyl group. HF Specific examples of when R is a hydrogen atom include those described in JP 2010-116550 A.HF Specific examples of the repeating units A8 and A12 when is a trifluoromethyl group include those described in JP-A-2010-77404. Examples of the repeating units A8 and A12 include those described in JP-A-2012-246265 and JP-A-2012-246426.

[0112] In formulae (A7) and (A11), Xa - is a non-nucleophilic counterion. - Examples of non-nucleophilic counter ions represented by the formula (I) include those described in JP-A-2010-113209 and JP-A-2007-145797.

[0113] Preferred examples of the anion of the monomer that provides the repeating units A10 and A14 include, but are not limited to, those shown below. [ka]

[0114] [ka]

[0115] In formulas (A7) to (A14), R 41 ~R 58 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 1Examples of the hydrocarbyl group include the same as those exemplified as the hydrocarbyl group represented by the formula: In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like.

[0116] Also, R 41 and R 42 may be bonded to each other to form a ring together with the sulfur atom to which they are attached, R 43 and R 44 , R 46 and R 47 , or R 49 and R 50 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. Examples of the ring formed in this case include those represented by the following formula: [ka] (In the formula, the dashed lines represent bonds.)

[0117] Specific examples of the sulfonium cations in the repeating units A8 to A10 include, but are not limited to, those shown below. [ka]

[0118] [ka]

[0119] [ka]

[0120]

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[0121]

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[0122]

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[0123]

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[0124]

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[0125]

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[0126]

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[0127]

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[0128]

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[0129]

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[0130]

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[0131]

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[0132]

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[0133]

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[0134]

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[0135]

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[0136]

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[0137]

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[0138]

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[0139]

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[0140]

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[0141] [ka]

[0142] [ka]

[0143] Specific examples of the iodonium cations in the repeating units A12 to A14 include, but are not limited to, those shown below. [ka]

[0144] [ka]

[0145] The repeating units A7 to A14 are units that generate acid by irradiation with high energy rays. It is considered that the inclusion of these units in the polymer appropriately suppresses acid diffusion, and a pattern with reduced LER can be obtained. In addition, the inclusion of these units in the polymer suppresses the phenomenon in which acid volatilizes from the exposed area and reattaches to the unexposed area during baking in a vacuum, and is therefore effective in reducing LER and reducing defects due to suppression of undesired negative reactions in the unexposed areas.

[0146] The repeating units A7 to A14 may be used alone or in combination of two or more.

[0147] The polymer may contain a (meth)acrylic acid ester unit having an adhesive group such as a lactone structure or a hydroxy group other than a phenolic hydroxy group, or other repeating unit, in order to finely adjust the properties of the resist film.

[0148] Examples of the (meth)acrylic acid ester unit having the adhesive group include a repeating unit represented by the following formula (A15) (hereinafter also referred to as repeating unit A15), a repeating unit represented by the following formula (A16) (hereinafter also referred to as repeating unit A16), and a repeating unit represented by the following formula (A17) (hereinafter also referred to as repeating unit A17). These units do not exhibit acidity and can be used auxiliary as units that impart adhesion to a substrate or units that adjust solubility. [ka]

[0149] In formulas (A15) to (A17), R A R are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 61 R is -O- or a methylene group. 62 is a hydrogen atom or a hydroxyl group. 63 represents a saturated hydrocarbyl group having 1 to 4 carbon atoms. h represents an integer of 0 to 3. The repeating units A15 to A17 may be used alone or in combination of two or more kinds.

[0150] In the polymer, the total content of the repeating units A1 and A6 is preferably 5 to 70 mol %, more preferably 10 to 60 mol %, in order to obtain the effect of promoting the negativation reaction. The content of the repeating unit A1 alone is preferably 5 to 70 mol %, more preferably 10 to 50 mol %, in order to develop good etching resistance. The content of the repeating unit A2 is preferably 30 to 95 mol %, more preferably 50 to 85 mol %, in order to obtain a high contrast between the part that is negated by high-energy ray irradiation and the part that is not irradiated (part that is not negated) for the purpose of obtaining high resolution. The content of the repeating units A3 to A5 is preferably 0 to 30 mol %, more preferably 0 to 20 mol %, in order to obtain the effect of improving etching resistance. It is to be noted that the polymer may contain other repeating units in an amount of 0 to 30 mol %, preferably 0 to 20 mol %.

[0151] When the polymer does not contain repeating units A7 to A14, the content of repeating unit A2 in the polymer is preferably 25 to 95 mol %, more preferably 40 to 85 mol %. The content of repeating units A3 to A5 is preferably 0 to 30 mol %, more preferably 3 to 20 mol %. The content of repeating unit A5 is preferably 5 to 70 mol %, more preferably 10 to 60 mol %. The polymer may contain other repeating units in an amount of 0 to 30 mol %, preferably 0 to 20 mol %.

[0152] When the polymer contains repeating units A7 to A14, the content of repeating unit A2 in the polymer is preferably 25 to 94.5 mol %, more preferably 36 to 85 mol %. The content of repeating units A3 to A5 is preferably 0 to 30 mol %, more preferably 3 to 20 mol %. The content of repeating unit A5 is preferably 5 to 70 mol %, more preferably 10 to 60 mol %. The total content of repeating units A1 to A5 is preferably 60 to 99.5 mol %. The content of repeating units A7 to A14 is preferably 0.5 to 20 mol %, more preferably 1 to 10 mol %. The polymer may contain other repeating units in an amount of 0 to 30 mol %, preferably 0 to 20 mol %.

[0153] The polymer can be synthesized by copolymerizing each monomer protected by a protecting group as necessary by a known method, and then carrying out a deprotection reaction as necessary. The copolymerization reaction is not particularly limited, but is preferably radical polymerization or anionic polymerization. For these methods, reference can be made to International Publication No. 2006 / 121096, JP-A No. 2008-102383, JP-A No. 2008-304590, and JP-A No. 2004-115630.

[0154] [Chemically amplified negative resist composition] The chemically amplified negative resist composition of the present invention contains (A) a base polymer containing the above-mentioned polymer.

[0155] In this case, the repeating units A1 to A6 preferably account for 60 mol % or more, more preferably 70 mol % or more, and even more preferably 80 mol % or more of the total repeating units in the polymer, which ensures that the properties required for the chemically amplified negative resist composition of the present invention are obtained.

[0156] The polymer preferably has a weight average molecular weight (Mw) of 1000 to 50000, more preferably 2000 to 20000. If Mw is 1000 or more, there is no risk of the phenomenon that the head of the pattern becomes rounded, the resolution decreases, and the LER deteriorates, as has been known in the past. On the other hand, if Mw is 50000 or less, there is no risk of the LER increasing, particularly when forming a pattern with a pattern line width of 100 nm or less. In the present invention, Mw is a value measured in terms of polystyrene by gel permeation chromatography (GPC).

[0157] The polymer preferably has a narrow molecular weight distribution (Mw / Mn) of 1.0 to 2.0, particularly 1.0 to 1.8, in which case the polymer is free from foreign matter on the pattern and from deterioration of the pattern shape after development.

[0158] The base polymer (A) may contain two or more polymers having different composition ratios, Mw, and Mw / Mn. In particular, a polymer not containing the repeating units A7 to A14 may be used in combination with a polymer containing the repeating units A7 to A14. In this case, the content of the polymer not containing the repeating units A7 to A14 in the chemically amplified negative resist composition of the present invention is preferably 2 to 5000 parts by mass, and more preferably 10 to 1000 parts by mass, per 100 parts by mass of the polymer not containing the repeating units A7 to A14.

[0159] When the chemically amplified negative resist composition is used for mask preparation, the coating film thickness in the most advanced generation is 150 nm or less, preferably 100 nm or less. The dissolution rate of the base polymer in an alkaline developer (e.g., 2.38% by mass tetramethylammonium hydroxide (TMAH) aqueous solution) is generally a strong development process in order to reduce defects caused by resist residues, and is preferably 80 nm / sec or less, more preferably 50 nm / sec or less, in order to form a fine pattern. In addition, for example, when preparing an LSI chip from a wafer, when the chemically amplified negative resist composition of the present invention is used in an EUV exposure process, it is necessary to pattern a fine line of 50 nm or less, so the coating film thickness is often 100 nm or less, and since the pattern is likely to deteriorate due to development due to the thin film, the dissolution rate of the polymer used is preferably 80 nm / sec or less, more preferably 50 nm / sec or less.

[0160] [(B) Acid generator] The chemically amplified negative resist composition of the present invention may contain an acid generator as component (B). Examples of such acid generators include compounds (photoacid generators) that generate acid in response to actinic rays or radiation. The photoacid generator is not particularly limited as long as it is a compound that generates acid when irradiated with high-energy rays. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate-type acid generators.

[0161] Specific examples of the photoacid generator include nonafluorobutanesulfonate, partially fluorinated sulfonates described in JP-A-2012-189977, paragraphs

[0247] to

[0251] , partially fluorinated sulfonates described in JP-A-2013-101271, paragraphs

[0261] to

[0265] , those described in JP-A-2008-111103, paragraphs

[0122] to

[0142] , and those described in JP-A-2010-215608, paragraphs

[0080] to

[0081] , etc. Among these, arylsulfonate-type or alkane sulfonate-type photoacid generators are preferred because they generate an acid of suitable strength for reacting the (C) crosslinking agent described later with the (A) base polymer.

[0162] In order to obtain the effect of improving LER by combining the photoacid generator with a quencher, component (E), which will be described later, the pKa of the acid generated from the photoacid generator is -3.0 or more, preferably in the range of -3.0 to 2.0, and more preferably in the range of -2.0 to 1.5.

[0163] Such an acid generator is preferably a compound having an anion of the structure shown below: Examples of the counter cation include those exemplified as specific examples of the sulfonium cations in the repeating units A8 to A10 and those exemplified as specific examples of the iodonium cations in the repeating units A12 to A14. [ka]

[0164] [ka]

[0165] [ka]

[0166] [ka]

[0167]

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[0168]

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[0169]

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[0170]

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[0171]

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[0172]

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[0173]

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[0174]

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[0175]

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[0176]

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[0177]

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[0178]

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[0179]

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[0180]

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[0181]

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[0182]

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[0183]

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[0184]

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[0185]

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[0186]

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[0187]

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[0188]

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[0189]

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[0190]

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[0191]

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[0192]

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[0193]

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[0194]

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[0195]

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[0196]

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[0197]

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[0198]

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[0199]

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[0200]

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[0201]

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[0202]

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[0203]

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[0204]

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[0205]

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[0206]

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[0207]

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[0224] When the chemically amplified negative resist composition of the present invention contains an acid generator (B), 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 base polymer (A). When the base polymer contains repeating units A7 to A14 (i.e., when it is a polymer-bound acid generator), the incorporation of the acid generator (B) may be omitted. The acid generator (B) may be used alone or in combination of two or more kinds.

[0225] [(C) Crosslinking agent] The chemically amplified negative resist composition of the present invention may contain a crosslinking agent as component (C). Specific examples of the crosslinking agent include epoxy compounds, melamine compounds, guanamine compounds, glycoluril compounds or urea compounds, isocyanate compounds, azide compounds, and compounds containing double bonds such as alkenyloxy groups, all of which are substituted with at least one group selected from a methylol group, an alkoxymethyl group, and an acyloxymethyl group. These may be used as additives or may be introduced as pendant groups into the polymer side chain. Compounds containing hydroxyl groups may also be used as crosslinking agents.

[0226] Examples of the epoxy compound include tris(2,3-epoxypropyl)isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

[0227] Examples of the melamine compound include compounds in which 1 to 6 methylol groups are methoxymethylated, such as hexamethylol melamine, hexamethoxymethyl melamine, and hexamethylol melamine, or mixtures thereof; and compounds in which 1 to 6 methylol groups are acyloxymethylated, such as hexamethoxyethyl melamine, hexaacyloxymethyl melamine, and hexamethylol melamine, or mixtures thereof.

[0228] Examples of the guanamine compound include compounds in which 1 to 4 methylol groups are methoxymethylated, such as tetramethylol guanamine, tetramethoxymethyl guanamine, and tetramethylol guanamine, and mixtures thereof; and compounds in which 1 to 4 methylol groups are acyloxymethylated, such as tetramethoxyethyl guanamine, tetraacyloxyguanamine, and tetramethylol guanamine, and mixtures thereof.

[0229] Examples of the glycoluril compound include compounds in which 1 to 4 methylol groups are methoxymethylated, such as tetramethylol glycoluril, tetramethoxymethyl glycoluril, and tetramethylol glycoluril, or mixtures thereof; and compounds in which 1 to 4 methylol groups are acyloxymethylated in tetramethylol glycoluril, or mixtures thereof.

[0230] Examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, tetramethylol urea, and other compounds in which 1 to 4 methylol groups are methoxymethylated, or mixtures thereof, and tetramethoxyethyl urea.

[0231] Examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

[0232] Examples of the azide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0233] Examples of the compound containing an alkenyloxy group include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, and trimethylolpropane trivinyl ether.

[0234] In the chemically amplified negative resist composition of the present invention, the content of the (C) crosslinking agent is preferably 0.1 to 50 parts by mass, more preferably 1 to 30 parts by mass, relative to 80 parts by mass of the (A) base polymer. Within the above range, there is little risk of patterns being connected together and the resolution being reduced. The (C) crosslinking agent may be used alone or in combination of two or more types.

[0235] [(D) Fluorine atom-containing polymer] The chemically amplified negative resist composition of the present invention, for the purposes of increasing contrast, suppressing chemical flare of acid upon irradiation with high-energy rays, shielding mixing of acid from the antistatic film in the process of applying an antistatic film material onto the resist film, and suppressing unexpected and unnecessary pattern degradation, may contain, as component (D), a fluorine-containing polymer that contains at least one selected from the group consisting of a repeating unit represented by formula (D1) below (hereinafter also referred to as repeating unit D1), a repeating unit represented by formula (D2) below (hereinafter also referred to as repeating unit D2), a repeating unit represented by formula (D3) below (hereinafter also referred to as repeating unit D3), and a repeating unit represented by formula (D4) below (hereinafter also referred to as repeating unit D4), and may further contain at least one selected from the group consisting of a repeating unit represented by formula (D5) below (hereinafter also referred to as repeating unit D5) and a repeating unit represented by formula (D6) below (hereinafter also referred to as repeating unit D6). The fluorine atom-containing polymer also functions as a surfactant, and is therefore effective against development defects since it can prevent insoluble matter from re-adhering to the substrate during the development process. [ka]

[0236] In the formulas (D1) to (D6), x is 1, 2, or 3. y is an integer satisfying 0≦y≦5+2z−x. z is 0 or 1. k is 1, 2, or 3. R C R are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. D R is each independently a hydrogen atom or a methyl group. 101 , R 102 , R 104 and R 105 R are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. 103 , R 106 , R 107 and R 108 each independently represents a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or an acid labile group; R103 , R 106 , R 107 and R 108 When R is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be present between the carbon-carbon bonds. 109 R is a hydrogen atom or a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a heteroatom-containing group interposed between the carbon-carbon bonds. 110 R is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a heteroatom-containing group between its carbon-carbon bonds. 111 Z is a saturated hydrocarbyl group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, and a part of the -CH2- in the saturated hydrocarbyl group may be substituted with an ester bond or an ether bond. 1 Z is a (k+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (k+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. 3 is a single bond, -O-, *-C(=O)-OZ 31 -Z 32 - or -C(=O)-NH-Z 31 -Z 32 -It is. 31 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. 32 is a single bond, an ester bond, an ether bond or a sulfonamide bond. * is a bond to a carbon atom of the main chain.

[0237] In formulas (D1) and (D2), R 101 , R 102 , R 104 and R 105The saturated hydrocarbyl group having 1 to 10 carbon atoms represented by the formula (I) may be linear, branched or cyclic, and specific examples thereof include alkyl groups having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group or an n-decyl group; and cyclic saturated hydrocarbyl groups having 3 to 10 carbon atoms, such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, an adamantyl group or a norbornyl group. Of these, saturated hydrocarbyl groups having 1 to 6 carbon atoms are preferred.

[0238] In formulas (D1) to (D4), R 103 , R 106 , R 107 and R 108 The hydrocarbyl group having 1 to 15 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include an alkyl group having 1 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms, and an alkynyl group having 2 to 15 carbon atoms, and an alkyl group having 1 to 15 carbon atoms is preferred. In addition to the above, examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, an n-tetradecyl group, and an n-pentadecyl group. Examples of the fluorinated hydrocarbyl group include a group in which some or all of the hydrogen atoms bonded to the carbon atoms of the above-mentioned hydrocarbyl group are substituted with fluorine atoms.

[0239] In formula (D4), Z 1 Examples of the (k+1)-valent hydrocarbon group having 1 to 20 carbon atoms and represented by the formula (1) include an alkyl group having 1 to 20 carbon atoms or a group in which k hydrogen atoms have been removed from a cyclic saturated hydrocarbyl group having 3 to 20 carbon atoms. 1Examples of the (k+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms represented by the following formula include groups in which at least one hydrogen atom of the above-mentioned (k+1)-valent hydrocarbon group has been substituted with a fluorine atom.

[0240] Specific examples of the repeating units D1 to D4 include, but are not limited to, those shown below. C is the same as above. [ka]

[0241] [ka]

[0242] [ka]

[0243] In formula (D5), R 109 and R 110 Examples of the hydrocarbyl group having 1 to 5 carbon atoms represented by the formula (1) include an alkyl group, an alkenyl group, and an alkynyl group, with an alkyl group being preferred. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and an n-pentyl group. In addition, a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom may be present between the carbon-carbon bonds of the hydrocarbyl group.

[0244] In formula (D5), -OR 109 is preferably a hydrophilic group. In this case, R 109 is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms and an oxygen atom intervening between the carbon-carbon bonds, or the like.

[0245] In formula (D5), Z 2 is preferably *-C(=O)-O- or *-C(=O)-NH-. Dis preferably a methyl group. 2 The presence of a carbonyl group in R improves the acid trapping ability of the antistatic film. D When the methyl group is used, the polymer becomes more rigid with a higher glass transition temperature (Tg), which suppresses the diffusion of acid. This improves the stability of the resist film over time, and the resolution and pattern shape do not deteriorate.

[0246] Examples of the repeating unit D5 include, but are not limited to, those shown below. In the following formula, R D is the same as above. [ka]

[0247] [ka]

[0248] In formula (D6), Z 3 The saturated hydrocarbylene group having 1 to 10 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include a methanediyl group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,1-diyl group, a propane-1,2-diyl group, a propane-1,3-diyl group, a propane-2,2-diyl group, a butane-1,1-diyl group, a butane-1,2-diyl group, a butane-1,3-diyl group, a butane-2,3-diyl group, a butane-1,4-diyl group, and a 1,1-dimethylethane-1,2-diyl group.

[0249] In formula (D6), R 111 The saturated hydrocarbyl group having 1 to 20 carbon atoms and at least one hydrogen atom of which is substituted with a fluorine atom, represented by the formula (I) may be linear, branched or cyclic, and specific examples thereof include an alkyl group having 1 to 20 carbon atoms or a cyclic saturated hydrocarbyl group having 3 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom.

[0250] Examples of the repeating unit D6 include, but are not limited to, those shown below. In the following formula, R D is the same as above. [ka]

[0251] [ka]

[0252] [ka]

[0253] [ka]

[0254] The content of the repeating units D1 to D4 is preferably 15 to 95 mol %, more preferably 20 to 85 mol %, based on all repeating units of the fluorine atom-containing polymer. The content of the repeating units D5 and / or D6 is preferably 5 to 85 mol %, more preferably 15 to 80 mol %, based on all repeating units of the fluorine atom-containing polymer. The repeating units D1 to D6 may be used alone or in combination of two or more.

[0255] The fluorine atom-containing polymer may contain other repeating units in addition to the repeating units described above. Examples of such repeating units include those described in paragraphs

[0046] to

[0078] of JP2014-177407A. When the fluorine atom-containing polymer contains other repeating units, the content of such other repeating units is preferably 50 mol% or less of the total repeating units of the fluorine atom-containing polymer.

[0256] The fluorine-containing polymer can be synthesized by copolymerizing each monomer protected by a protecting group as necessary by a known method, and then carrying out a deprotection reaction as necessary. The copolymerization reaction is not particularly limited, but is preferably radical polymerization or anionic polymerization. For these methods, JP-A-2004-115630 can be referred to.

[0257] The Mw of the fluorine atom-containing polymer is preferably 2000 to 50000, more preferably 3000 to 20000. If the Mw is less than 2000, the diffusion of the acid is promoted, which may result in deterioration of the resolution and deterioration of the stability over time. If the Mw is too large, the solubility in the solvent may decrease, which may cause coating defects. Furthermore, the Mw / Mn of the fluorine atom-containing polymer is preferably 1.0 to 2.2, more preferably 1.0 to 1.7.

[0258] When the chemically amplified negative resist composition of the present invention contains the fluorine atom-containing polymer (D), the content thereof is preferably 0.01 to 30 parts by mass, 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 (A). The fluorine atom-containing polymer (D) may be used alone or in combination of two or more kinds.

[0259] [(E) Quencher] The chemically amplified negative resist composition of the present invention preferably contains a quencher as component (E). In the present invention, the quencher refers to a material that traps the acid generated by the photoacid generator in the chemically amplified resist composition, thereby preventing the acid from diffusing into unexposed areas and forming a desired pattern.

[0260] The quencher may be a conventional basic compound. Examples of conventional basic compounds include primary, secondary, and tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxy group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, and carbamates. In particular, the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, particularly amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonic acid ester bond, or compounds having a carbamate group described in JP-A-3790649 are preferred. Preferable examples include tris[2-(methoxymethoxy)ethyl]amine, tris[2-(methoxymethoxy)ethyl]amine-N-oxide, dibutylaminobenzoic acid, morpholine derivatives, imidazole derivatives, etc. By adding such a basic compound, for example, it is possible to further suppress the diffusion rate of the acid in the resist film and correct the shape.

[0261] Further, the quencher may be an onium salt such as a sulfonium salt, an iodonium salt, or an ammonium salt of a carboxylic acid not fluorinated at the α-position, as described in JP-A-2008-158339. A sulfonic acid, an imide acid, or a methide acid fluorinated at the α-position is necessary for deprotecting an acid labile group, but a carboxylic acid not fluorinated at the α-position is released by salt exchange with an onium salt not fluorinated at the α-position. A carboxylic acid not fluorinated at the α-position hardly undergoes a deprotection reaction, and therefore functions as a quencher.

[0262] An example of an onium salt of a carboxylic acid not fluorinated at the α-position is one represented by the following formula (E1). [ka]

[0263] In formula (E1), R 201 represents a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hydrogen atom or a heteroatom, but excludes those in which the hydrogen atom bonded to the carbon atom at the α-position of the carboxy group is substituted with a fluorine atom or a fluoroalkyl group.

[0264] R 201 The hydrocarbyl group represented by the formula (1) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 40 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a tert-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, or an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, a tricyclo[5.2.1.0 2,6 ]Cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms, such as a decyl group, an adamantyl group, and an adamantylmethyl group; alkenyl groups having 2 to 40 carbon atoms, such as a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 40 carbon atoms, such as a cyclohexenyl group; 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, 5-butylphenyl group, 6-butylphenyl group, 7-butylphenyl group, 8-butylphenyl group, 9-butylphenyl group, 10-butylphenyl group, 11-butylphenyl group, 12-butylphenyl group, 13-butylphenyl group, 14-butylphenyl group, 15-butylphenyl group, 16-butylphenyl group, 17-butylphenyl group, 18-butylphenyl group, 19-butylphenyl group, 20-butylphenyl group, 21-butylphenyl group, 22-butylphenyl group, 23-butylphenyl group, 24-butylphenyl group, 25-butylphenyl group, 26-butylphenyl group, 27-butylphenyl group, 28-butylphenyl group, 29-butylphenyl group, 30-butylphenyl group, 31-butylphenyl group, 32-butylphenyl group, 33-butylphenyl group, 34-butylphenyl group, 35-butylphenyl group, 36-butylphenyl group, 37-butylphenyl group, 38-butylphenyl group, 39-butylphenyl group, 40-butylphenyl group, 41-butylphenyl group, 42-butylphenyl group, 43-butylphenyl group, 44-butylphenyl group, 45-butylphenyl group, 46-butylphenyl group, 4 Examples of such aryl groups include aryl groups having 6 to 40 carbon atoms, such as arylphenyl groups (e.g., 4-n-butylphenyl group, 4-n-butylphenyl group), di- or trialkylphenyl groups (e.g., 2,4-dimethylphenyl group, 2,4,6-triisopropylphenyl group), alkylnaphthyl groups (e.g., methylnaphthyl group, ethylnaphthyl group), dialkylnaphthyl groups (e.g., dimethylnaphthyl group, diethylnaphthyl group), and aralkyl groups having 7 to 40 carbon atoms, such as benzyl group, 1-phenylethyl group, and 2-phenylethyl group.

[0265] In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, a nitrogen atom or a halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom, and as a result, the hydrocarbyl group may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like. Examples of the hydrocarbyl group containing a heteroatom include heteroaryl groups such as a thienyl group; alkoxyphenyl groups such as a 4-hydroxyphenyl group, a 4-methoxyphenyl group, a 3-methoxyphenyl group, a 2-methoxyphenyl group, a 4-ethoxyphenyl group, a 4-tert-butoxyphenyl group, and a 3-tert-butoxyphenyl group; alkoxynaphthyl groups such as a methoxynaphthyl group, an ethoxynaphthyl group, an n-propoxynaphthyl group, and an n-butoxynaphthyl group; dialkoxynaphthyl groups such as a dimethoxynaphthyl group and a diethoxynaphthyl group; and aryloxoalkyl groups such as a 2-aryl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, and a 2-(2-naphthyl)-2-oxoethyl group.

[0266] In formula (E1), Mq A + is an onium cation. The onium cation is preferably a sulfonium cation, an iodonium cation, or an ammonium cation, and more preferably a sulfonium cation or an iodonium cation. Specific examples of the sulfonium cation include the same as those exemplified as the sulfonium cations of the repeating units A7 to A9. Specific examples of the iodonium cation include the same as those exemplified as the iodonium cations of the repeating units A11 to A13.

[0267] Examples of the anion of the onium salt represented by formula (E1) include, but are not limited to, those shown below. [ka]

[0268] [ka]

[0269] [ka]

[0270] As the quencher, a sulfonium salt of an iodized benzene ring-containing carboxylic acid represented by the following formula (E2) can also be suitably used. [ka]

[0271] In formula (E2), s is an integer of 1 to 5. t is an integer of 0 to 3, provided that 1≦s+t≦5. u is an integer of 1 to 3.

[0272] In formula (E2), R 211 represents a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms, in which some or all of the hydrogen atoms may be substituted with halogen atoms, or -N(R 211A )-C(=O)-R 211B Or -N(R 211A )-C(=O)-OR 211B R 211A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. 211B is a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms. When t and / or u is 2 or more, each R 211 may be the same or different from each other.

[0273] In formula (E2), L 1 is a single bond or a (u+1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxy group, and a carboxy group. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, and saturated hydrocarbylsulfonyloxy group may be linear, branched, or cyclic.

[0274] In formula (E2), R 212 , R 213 and R 214 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms. In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxy group, a carboxy group, a halogen atom, an oxo group, a cyano group, a nitro group, a sultone ring, a sulfo group, or a sulfonium salt-containing group, and some of the -CH2- of the hydrocarbyl group may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond, or a sulfonate ester bond. In addition, R 212 and R 213 may be bonded to each other to form a ring together with the sulfur atom to which they are attached.

[0275] Specific examples of the compound represented by formula (E2) include those described in JP 2017-219836 A. The compound represented by formula (E2) has high absorption, a high sensitizing effect, and a high acid diffusion control effect.

[0276] As the quencher, a nitrogen-containing carboxylate compound represented by the following formula (E3) can also be used. [ka]

[0277] In formula (E3), R 221 ~R 224 Each independently represents a hydrogen atom, -L 2 -CO2 - or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 221 and R 222 And, R 222 and R 223 and, or R 223 and R 224 and may be bonded to each other to form a ring together with the carbon atoms to which they are attached. 2 R is a single bond or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 225 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom.

[0278] In formula (E3), ring R r is a ring containing carbon atoms and nitrogen atoms and having 2 to 6 carbon atoms, and some or all of the hydrogen atoms bonded to the carbon atoms of the ring are hydrocarbyl groups having 1 to 20 carbon atoms, or -L 2 -CO2 - and a part of the carbon atoms of the ring may be substituted with a sulfur atom, an oxygen atom, or a nitrogen atom. The ring may be an alicyclic ring or an aromatic ring, and is preferably a 5-membered or 6-membered ring, and specific examples thereof include a pyridine ring, a pyrrole ring, a pyrrolidine ring, a piperidine ring, a pyrazole ring, an imidazoline ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, an imidazoline ring, an oxazole ring, a thiazole ring, a morpholine ring, a thiazine ring, and a triazole ring.

[0279] The carboxylic acid onium salt represented by formula (E3) has at least one -L 2 -CO2 - That is, R 221 ~R 224 At least one of the following is -L 2-CO2 - and / or at least one of the hydrogen atoms bonded to the carbon atom of the ring R is -L 2 -CO2 - is replaced by

[0280] In formula (E3), Mq B + is a sulfonium cation, an iodonium cation or an ammonium cation, preferably a sulfonium cation. Specific examples of the sulfonium cation include the same as those exemplified as the sulfonium cations of the repeating units A7 to A9.

[0281] Examples of the anion of the compound represented by formula (E3) include, but are not limited to, those shown below. [ka]

[0282] [ka]

[0283] [ka]

[0284] [ka]

[0285] [ka]

[0286] [ka]

[0287] Alternatively, a weak acid betaine type compound may be used as the quencher, specific examples of which include, but are not limited to, those shown below. [ka]

[0288] Further examples of the quencher include polymer-type quenchers described in JP 2008-239918 A. These improve the rectangularity of the resist pattern by being oriented on the surface of the resist film. Polymer-type quenchers also have the effect of preventing film loss of the pattern and rounding of the pattern top when a protective film for immersion exposure is applied.

[0289] When the chemically amplified negative resist composition of the present invention contains a quencher (E), the content thereof is preferably 0 to 50 parts by mass, and more preferably 0.1 to 40 parts by mass, relative to 80 parts by mass of the base polymer (A). The quencher (E) may be used alone or in combination of two or more kinds.

[0290] When the chemically amplified negative resist composition of the present invention contains both an acid generator, component (B), and a quencher, component (E), the content ratio of the acid generator to the quencher ((B) / (E)) is preferably less than 6, more preferably less than 5, and even more preferably less than 4. When the content ratio of the acid generator to the quencher contained in the chemically amplified negative resist composition is within the above range, acid diffusion can be sufficiently suppressed, and excellent resolution and dimensional uniformity can be obtained.

[0291] [(F) Organic solvent] The chemically amplified negative resist composition of the present invention may contain an organic solvent as component (F). The organic solvent is not particularly limited as long as it is capable of dissolving each component. Examples of such organic solvents include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] to

[0145] of JP-A-2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, and ethylene glycol monoethyl ether. Examples of suitable solvents include ethers such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, diethylene glycol dimethyl ether, etc.; esters such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, ethyl lactate (EL), ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol mono tert-butyl ether acetate, etc.; lactones such as γ-butyrolactone, etc.; and mixed solvents thereof.

[0292] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, PGME, cyclohexanone, EL, γ-butyrolactone, and mixed solvents thereof are preferable.

[0293] When the chemically amplified negative resist composition of the present invention contains an organic solvent (F), the content thereof is preferably 200 to 10,000 parts by mass, and more preferably 400 to 6,000 parts by mass, relative to 80 parts by mass of the base polymer (B). The organic solvent (F) may be used alone or in combination of two or more kinds.

[0294] [(G) Surfactant] The chemically amplified negative resist composition of the present invention may contain a commonly used surfactant in order to improve the coating property on the substrate. Examples of the surfactant include PF-636 (manufactured by OMNOVA SOLUTIONS), FC-4430 (manufactured by 3M), and the like. In addition, as many examples are described in JP-A-2004-115630, many of them are known, and the surfactant can be selected by referring to them. When the chemically amplified negative resist composition of the present invention contains the surfactant (G), the content thereof is preferably 0 to 5 parts by mass relative to 80 parts by mass of the base polymer (B). The surfactant (G) may be used alone or in combination of two or more kinds.

[0295] [Method of forming resist pattern] The method for forming a resist pattern of the present invention includes the steps of forming a resist film on a substrate using the above-mentioned chemically amplified negative resist composition, irradiating the resist film with a pattern using high-energy rays (i.e., exposing the resist film with high-energy rays), and developing the resist film irradiated with the pattern using an alkaline developer.

[0296] The substrate may be, for example, a substrate for manufacturing an integrated circuit (Si, SiO, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.), or a substrate for manufacturing a transmission or reflection mask circuit (Cr, CrO, CrON, MoSi2, Si, SiO, SiO2, SiON, SiONC, CoTa, NiTa, TaBN, SnO2, etc.). The chemically amplified negative resist composition is applied onto the substrate by a method such as spin coating so as to have a film thickness of 0.03 to 2 μm, and the composition 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.

[0297] Next, the resist film is exposed to a high-energy ray to irradiate a pattern. Examples of the high-energy ray include ultraviolet ray, far ultraviolet ray, excimer laser light (KrF, ArF, etc.), EUV, X-ray, γ-ray, synchrotron radiation, EB, etc. In the present invention, it is preferable to use EUV or EB for exposure.

[0298] When ultraviolet rays, far ultraviolet rays, excimer laser light, EUV, X-rays, gamma rays or synchrotron radiation is used as the high energy rays, a mask for forming a desired pattern is used and the exposure dose is preferably 1 to 500 mJ / cm. 2 , more preferably 10 to 400 mJ / cm 2 When EB is used, the exposure dose is preferably 1 to 500 μC / cm 2 directly to form the desired pattern. 2 , more preferably 10 to 400 μC / cm 2 Irradiate so that

[0299] The exposure may be performed by a conventional exposure method, or in some cases by an immersion method in which the space between the mask and the resist film is immersed in liquid. In this case, a water-insoluble protective film may be used.

[0300] Next, post-exposure baking (PEB) is performed on a hot plate, preferably at 60 to 150° C. for 1 to 20 minutes, more preferably at 80 to 140° C. for 1 to 10 minutes.

[0301] Thereafter, the substrate is developed using a developer of an alkaline aqueous solution of 0.1 to 5 mass %, preferably 2 to 3 mass %, TMAH or the like, for preferably 0.1 to 3 minutes, more preferably 0.5 to 2 minutes, by a conventional method such as a dip method, a puddle method or a spray method, to form a desired pattern on the substrate.

[0302] The chemically amplified negative resist composition of the present invention is useful because it can form a pattern with particularly good resolution and small LER. Also, the chemically amplified negative resist composition of the present invention is particularly useful for pattern formation on a substrate having a surface made of a material that is prone to pattern peeling or pattern collapse, since it is difficult to obtain adhesion of the resist pattern. Examples of such substrates include substrates having a sputtering film formed on the outermost surface of a chromium compound containing one or more light elements selected from metallic chromium, oxygen, nitrogen, and carbon, SiO, SiO x , a tantalum compound, a molybdenum compound, a cobalt compound, a nickel compound, a tungsten compound, or a tin compound in the outermost layer. The chemically amplified negative resist composition of the present invention is particularly useful for pattern formation using a photomask blank as the substrate. In this case, the photomask blank may be either a transmission type or a reflection type.

[0303] As a transmission type mask blank, a photomask blank having a light-shielding film made of a chromium-based material may be a photomask blank for a binary mask or a photomask blank for a phase shift mask. In the case of a photomask blank for a binary mask, the light-shielding film may have an antireflection layer and a light-shielding layer made of a chromium-based material, and the entire antireflection film on the surface layer side or only the surface layer side of the antireflection film on the surface layer side may be made of a chromium-based material, and the remaining part may be made of a silicon-based compound material that may contain a transition metal, for example. In the case of a photomask blank for a phase shift mask, a photomask blank for a phase shift mask having a chromium-based light-shielding film on a phase shift film may be the target.

[0304] The above-mentioned photomask blank having a chromium-based material in the outermost layer is very well known, as exemplified in JP2008-26500A and JP2007-302873A or as prior art therein, and detailed description will be omitted. For example, when forming a light-shielding film having an antireflection layer and a light-shielding layer using a chromium-based material, the following film configuration can be used.

[0305] When a light-shielding film having an anti-reflection layer and a light-shielding layer is formed using a chromium-based material, the layer structure may be such that the anti-reflection layer and the light-shielding layer are laminated in this order from the surface layer side, or the anti-reflection layer, the light-shielding layer, and the anti-reflection layer are laminated in this order. The anti-reflection layer and the light-shielding layer may each be multi-layered, and the composition between layers having different compositions may change discontinuously or may change continuously. As the chromium-based material to be used, a material containing light elements such as oxygen, nitrogen, and carbon in metal chromium is used. Specifically, metal chromium, chromium oxide, chromium nitride, chromium carbide, chromium oxide nitride, chromium carbide oxide, chromium nitride, chromium oxynitride, etc. may be used.

[0306] The reflective mask blank includes a substrate, a multilayer reflective film formed on one main surface (front surface) of the substrate, specifically, a multilayer reflective film that reflects exposure light such as EUV light, and an absorber film formed on the multilayer reflective film, specifically, an absorber film that absorbs exposure light such as EUV light and reduces reflectance. From the reflective mask blank (EUV reflective mask blank), a reflective mask (EUV reflective mask) having an absorber pattern (absorber film pattern) formed by patterning the absorber film is manufactured. The wavelength of EUV light used in EUV lithography is 13 to 14 nm, and is usually light with a wavelength of about 13.5 nm.

[0307] The multilayer reflective film is usually preferably provided in contact with one main surface of the substrate, but it is also possible to provide an undercoat film between the substrate and the multilayer reflective film, provided that the effect of the present invention is not lost. The absorber film may be formed in contact with the multilayer reflective film, but a protective film (protective film for the multilayer reflective film) may be provided between the multilayer reflective film and the absorber film, preferably in contact with the multilayer reflective film, more preferably in contact with the multilayer reflective film and the absorber film. The protective film is used to protect the multilayer reflective film during processing such as cleaning and correction. In addition, the protective film is preferably one that has the function of protecting the multilayer reflective film when the absorber film is patterned by etching, and preventing the oxidation of the multilayer reflective film. On the other hand, a conductive film used for electrostatic chucking the reflective mask to the exposure device may be provided under the other main surface (back surface) that is the surface opposite to the one main surface of the substrate, preferably in contact with the other main surface. In this embodiment, one main surface of the substrate is the front surface and the upper side, and the other main surface is the back surface and the lower side, but the front and back and the top and bottom of both are defined for convenience, and the one main surface and the other main surface are either of the two main surfaces (film formation surfaces) of the substrate, and the front and back and the top and bottom are interchangeable. More specifically, it can be formed by a method such as that exemplified in JP 2021-139970 A or the prior art therein.

[0308] According to the method for forming a resist pattern of the present invention, even when a substrate (e.g., a transmission type or reflection type mask blank) whose outermost surface is made of a material that is likely to affect the resist pattern shape, such as a material containing chromium, silicon or tantalum, is used, it is possible to obtain a pattern having extremely high resolution, small LER, excellent rectangularity, and excellent pattern fidelity. EXAMPLES

[0309] The present invention will be specifically described below with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples. The structures of the compounds were confirmed by measuring the molecular ion peaks using mass spectrometry (LC: Agilent 1100 model, MASS: Agilent LC / MSD model). The value of this molecular ion peak is indicated by "MASS".

[0310] [1] Synthesis of monomer [Example 1-1] Synthesis of Monomer A-1 [ka] (In the formula, Me is a methyl group.)

[0311] (1) Synthesis of Monomer A-1 Methyl magnesium chloride (3.0M THF solution, 160mL) and THF (160mL) were charged in a reaction vessel under a nitrogen atmosphere, and the temperature in the reaction vessel was heated to 50°C. A solution of methyl 3-acenaphthylenecarboxylate (42.0g) dissolved in THF (80mL) was added dropwise while maintaining the temperature in the reaction vessel at 60°C or less. After the dropwise addition, the temperature in the reaction vessel was set to 60°C and the reaction was aged for 3 hours. After aging, the reaction solution was cooled in an ice bath, and a solution consisting of ammonium chloride (48g), 20% by mass hydrochloric acid (48g) and water (240g) was added dropwise to stop the reaction. Ethyl acetate (400mL) was added to the reaction solution to extract the target product, which was subjected to a normal aqueous work-up, the solvent was distilled off, and the product was purified by silica gel chromatography to obtain Monomer A-1 as a colorless oil (yield 35.3g, yield 84%).

[0312] The results of mass spectrometry of Monomer A-1 are shown below. MASS:211.1[M+H] +

[0313] [Examples 1-2 to 1-9] Synthesis of Monomers A-2 to A-6 Using the corresponding raw materials, the following monomers A-2 to A-6 were synthesized. [ka] (In the formula, Ac is an acetyl group.)

[0314] [2] Polymer synthesis Among the monomers used in the synthesis of the polymer, those other than the monomers A-1 to A-6 are as follows. [ka]

[0315] [ka]

[0316] [ka]

[0317] [ka]

[0318] [ka]

[0319] [Example 2-1] Synthesis of polymer P-1 In a nitrogen atmosphere, 23.6 g of 4-acetoxystyrene, 16.4 g of Monomer A-1, 8.2 g of dimethyl-2,2'-azobis(2-methylpropionate) (manufactured by Wako Pure Chemical Industries, Ltd., trade name V601), and 112 g of methyl ethyl ketone as a solvent were added to a 200 mL dropping cylinder to prepare solution A. Furthermore, 38 g of methyl ethyl ketone was added to another 500 mL polymerization flask under a nitrogen atmosphere, heated to 80 ° C., and while maintaining the temperature, solution A was dropped over 4 hours. After the dropwise addition, stirring was continued for 18 hours while maintaining the polymerization temperature at 80 ° C., and then cooled to room temperature. The obtained polymerization liquid was dropped into 1400 g of hexane, and the precipitated solid was filtered off. The filtered solid was washed twice with 280 g of hexane. The obtained solid was dissolved in 160g of THF in a 1L flask under a nitrogen atmosphere, 17.7g of ethanolamine was added, and the mixture was stirred at 60°C for 3 hours. The reaction solution was concentrated under reduced pressure, and the resulting concentrate was dissolved in a mixed solvent of 225g of ethyl acetate and 100g of water, and the resulting solution was transferred to a separatory funnel, and 29g of acetic acid was added to perform a separation operation. The lower layer was distilled off, and 100g of water and 39g of pyridine were added to the obtained organic layer, and a separation operation was performed. The lower layer was distilled off, and 100g of water was further added to the obtained organic layer, and water washing and separation were performed. Water washing and separation were performed a total of 5 times. The organic layer after separation was concentrated and then dissolved in 150 g of acetone. The resulting acetone solution was dropped into 2000 g of water to obtain a crystallized precipitate, which was then filtered and washed with water. After suction filtration for 2 hours, the filtered product was again dissolved in 150 g of acetone. The resulting acetone solution was dropped into 2000 g of water to obtain a crystallized precipitate, which was then filtered, washed with water, and dried to obtain 26.5 g of the target polymer P-1 as a white solid. Polymer P-1 was 13 C-NMR, 1 Measurements by 1 H-NMR and GPC confirmed that the polymer was the one shown below. Note that Mw is a polystyrene-equivalent measurement by GPC using DMF as a solvent.

[0320] [ka]

[0321] [Examples 2-2 to 2-30, Comparative Examples 1-1 to 1-15] Synthesis of Polymers P-2 to P-30 and CP-1 to CP-15 The polymers shown in the following Tables 1 to 3 were synthesized in the same manner as in Example 2-1, except that the types and compounding ratios of each monomer were changed.

[0322] [Table 1]

[0323] [Table 2]

[0324] [Table 3]

[0325] [3] Preparation of chemically amplified negative resist composition [Examples 3-1 to 3-35, Comparative Examples 2-1 to 3-18] Chemically amplified negative resist compositions (R-1 to R-35, CR-1 to CR-18) were prepared by dissolving each component in an organic solvent according to the composition shown in Tables 4 to 6 below, and filtering each solution with a UPE filter and / or a nylon filter selected from 10 nm, 5 nm, 3 nm, and 1 nm sizes. The organic solvent used was a mixed solvent of 790 parts by mass of PGMEA, 1580 parts by mass of EL, and 1580 parts by mass of PGME. Some compositions contained fluorine atom-containing polymers (polymers FP-1 to FP-5) as additives, tetramethoxymethylglycoluril (TMGU) as a crosslinking agent, and PF-636 (manufactured by OMNOVA SOLUTIONS) as a surfactant.

[0326] [Table 4]

[0327] [Table 5]

[0328] [Table 6]

[0329] The structures of the photoacid generators PAG-A to PAG-E, the quenchers Q-1 to Q-5, and the fluorine atom-containing polymers FP-1 to FP-5 used in the resist compositions are as follows. [ka]

[0330] [ka]

[0331] [ka]

[0332] [2] EB lithography evaluation [Examples 4-1 to 4-35, Comparative Examples 3-1 to 3-18] Each chemically amplified negative resist composition (R-1 to R-35, CR-1 to CR-18) was spin-coated onto a 152 mm square mask blank, the outermost surface of which was a silicon oxide film, that had been treated with hexamethyldisilazane vapor prime using ACT-M (Tokyo Electron Ltd.), and pre-baked on a hot plate at 110°C for 600 seconds to produce a resist film with a thickness of 80 nm. The thickness of the resulting resist film was measured using an optical measuring device Nanospec (Nanometrics). Measurements were performed at 81 points within the plane of the blank substrate, excluding the outer edge portion from the outer periphery to the inside by 10 mm, and the average thickness and thickness range were calculated. The film was exposed using an electron beam exposure device (EBM-5000plus, manufactured by NuFlare Technology, Inc., acceleration voltage 50 kV), subjected to PEB at 120° C. for 600 seconds, and developed with a 2.38 mass % TMAH aqueous solution to obtain a negative pattern.

[0333] The obtained resist patterns were evaluated as follows. The prepared patterned mask blanks were observed with an overhead SEM (scanning electron microscope), and the exposure dose required to resolve a 200 nm 1:1 line and space (LS) pattern at 1:1 was determined as the optimal exposure dose (μC / cm 2 ), and the minimum dimension at the exposure dose at which a 200 nm LS pattern is resolved at 1:1 is taken as the resolution (limiting resolution). For the 200 nm LS pattern obtained by irradiating with the optimal exposure dose, 80 edge detection was performed on each of the 32 edges of the 200 nm LS pattern using an SEM, and the triple value (3σ) of the standard deviation (σ) was obtained and this was taken as the LER. The pattern shape was judged visually to be rectangular or not. For the pattern fidelity evaluation, the Area Loss value (%) of one corner of the dot pattern was calculated when a 120 nm square dot pattern was arranged at a density of 36%, and the smaller the value, the better the rectangularity of the dot shape can be judged. The results are shown in Tables 7 and 8.

[0334] [Table 7]

[0335] [Table 8]

[0336] [3] Dry etching resistance evaluation [Examples 5-1 to 5-30, Comparative Examples 4-1 to 4-18] 2 g of each of the polymers shown in Tables 1 and 2 (polymers P-1 to P-30, comparative polymers CP-1 to CP-18) was dissolved in 10 g of cyclohexanone and filtered through a 0.2 μm filter to form a polymer solution on a Si substrate by spin coating to form a film with a thickness of 300 nm. The film was then evaluated under the following conditions. Etching test with CHF3 / CF4 gas: The difference in thickness of the polymer film before and after etching was determined using a dry etching apparatus TE-8500P manufactured by Tokyo Electron Limited. The etching conditions are as follows: Chamber pressure 40Pa RF power 1000W Gap 9mm CHF3 gas flow rate: 30mL / min CF4 gas flow rate: 30mL / min Ar gas flow rate: 100mL / min Time 60sec In this evaluation, a film with a smaller difference in film thickness, that is, a film with a smaller reduction in film thickness, indicates high etching resistance. The dry etching resistance results are shown in Tables 9 and 10.

[0337] [Table 9]

[0338] [Table 10]

[0339] As described above, it has been shown that the use of the chemically amplified negative resist composition of the present invention makes it possible to form a pattern with extremely high resolution and excellent LER, shape and pattern fidelity. It has also been confirmed that the polymer of the present invention has excellent dry etching resistance against CHF3 / CF4-based gases. The method for forming a resist pattern using the chemically amplified negative resist composition of the present invention is useful for semiconductor device manufacturing, particularly photolithography in processing a transmission or reflection mask blank.

Claims

1. A monomer represented by the following formula (A1): 【Chemistry 1】 (In the formula, a1 is 1 or 2. a2 is 0, 1 or 2. R A each independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 1 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom or a heteroatom. R 2 and R 3 are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms, or an aryl group having 6 to 15 carbon atoms, the hydrocarbyl group may be substituted with a hydroxy group or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, and the aryl group may have a substituent. 2 and R 3 cannot be a hydrogen atom at the same time. 2 and R 3 may be bonded to each other to form a ring together with the carbon atom to which they are bonded, and the -CH 2 A part of - may be substituted with -O- or -S-. W 1 is a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, an aliphatic hydrocarbylcarbonyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 15 carbon atoms, and the aryl group may have a substituent.

2. The monomer according to claim 1, represented by the following formula (A1-1): 【Chemistry 2】 (In the formula, a2, R A , R 1 , R 2 , R 3 and W 1 is the same as above.)

3. The monomer according to claim 2, represented by the following formula (A1-2): 【Chemistry 3】 (In the formula, a2, R A , R 1 , R 2 and R 3 is the same as above.)

4. A polymer comprising repeating units derived from the monomer of claim 1.

5. The polymer according to claim 4, further comprising a repeating unit represented by the following formula (A2): 【Chemistry 4】 (In the formula, b1 is 0 or 1. b2 is 0, 1 or 2. b3 is an integer satisfying 0≦b3≦5+2(b2)−b4. b4 is 1, 2 or 3. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 11 represents a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. A 1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and the —CH 2 A part of - may be replaced by -O-.

6. The polymer according to claim 4, further comprising at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (A3), a repeating unit represented by the following formula (A4), and a repeating unit represented by the following formula (A5): 【Chemistry 5】 (In the formula, c and d are each independently an integer of 0 to 4. e1 is 0 or 1. e2 is 0, 1 or 2. e3 is an integer of 0 to 5. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 21 and R 22 each independently represents a hydroxy group, a halogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. R 23 is a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms, a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group, a cyano group, a saturated hydrocarbylsulfinyl group having 1 to 20 carbon atoms, or a saturated hydrocarbylsulfonyl group having 1 to 20 carbon atoms. A 2 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and the —CH 2 A part of - may be replaced by -O-.

7. The polymer according to claim 4 , further comprising a repeating unit represented by the following formula (A6): 【Chemistry 6】 (In the formula, f1 is 0 or 1. f2 is 0, 1, or 2. f3 is an integer satisfying 0≦f3≦5+2(f2)−f4. f4 is 1, 2, or 3. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 31 represents a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom. R 32 and R 33 are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms, or an aryl group having 6 to 15 carbon atoms, the hydrocarbyl group may be substituted with a hydroxy group or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, and the aryl group may have a substituent. 32 and R 33 cannot be a hydrogen atom at the same time. 32 and R 33 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. A 3 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and the —CH 2 - may be replaced by -O-. W 2 is a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, an aliphatic hydrocarbylcarbonyl group having 2 to 10 carbon atoms, or an aryl group having 6 to 15 carbon atoms, and the aryl group may have a substituent.

8. The polymer according to claim 4, further comprising at least one repeating unit selected from the repeating units represented by the following formulas (A7) to (A14): 【Chemistry 7】 (In the formula, R B are each independently a hydrogen atom or a methyl group. X 1 each independently represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these groups; —O—X 11 -, -C(=O)-O-X 11 - or -C(=O)-NH-X 11 - and X 11 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. X 2 each independently represents a single bond or -X 21 -C(=O)-O-, and X 21 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. X 3 each independently represents a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -O-X 31 -, -C(=O)-O-X 31 - or -C(=O)-NH-X 31 - and X 31 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a group having 7 to 20 carbon atoms obtained by combining these, which may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. X 4 each independently represents a single bond or a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. g1 and g2 are each independently 0 or 1, 4 When is a single bond, g1 and g2 are 0. R 41 ~R 58 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 41 and R 42 may be bonded to each other to form a ring together with the sulfur atom to which they are attached, R 43 and R 44 , R 46 and R 47 , or R 49 and R 50 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. R HF is a hydrogen atom or a trifluoromethyl group. Xa - is a non-nucleophilic counterion.)

9. A chemically amplified negative resist composition comprising a base polymer comprising the polymer according to any one of claims 4 to 8.

10. 10. The chemically amplified negative resist composition according to claim 9, wherein the content of repeating units having an aromatic ring skeleton in all repeating units of the polymer contained in the base polymer is 60 mol % or more.

11. 10. The chemically amplified negative resist composition according to claim 9, further comprising (B) an acid generator.

12. 10. The chemically amplified negative resist composition according to claim 9, further comprising (C) a crosslinking agent.

13. 10. The chemically amplified negative resist composition according to claim 9, which does not contain a crosslinking agent.

14. The chemically amplified negative resist composition according to claim 9, further comprising (D) a fluorine atom-containing polymer which contains at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (D1), a repeating unit represented by the following formula (D2), a repeating unit represented by the following formula (D3), and a repeating unit represented by the following formula (D4), and which may further contain at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (D5) and a repeating unit represented by the following formula (D6): 【Chemistry 8】 (In the formula, x is 1, 2, or 3. y is an integer satisfying 0≦y≦5+2z−x. z is 0 or 1. k is 1, 2, or 3. R C each independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R D are each independently a hydrogen atom or a methyl group. R 101 , R 102 , R 104 and R 105 are each independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. R 103 , R 106 , R 107 and R 108 are each independently a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or an acid labile group; R 103 , R 106 , R 107 and R 108 When is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be present between the carbon-carbon bonds. R 109 is a hydrogen atom or a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a heteroatom-containing group interposed between the carbon-carbon bonds. R 110 is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a heteroatom-containing group between its carbon-carbon bonds. R 111 is a saturated hydrocarbyl group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, and the —CH 2 A part of the - may be substituted with an ester bond or an ether bond. Z 1 is a (k+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (k+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. Z 2 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. Z 3 is a single bond, -O-, *-C(=O)-O-Z 31 -Z 32 - or -C(=O)-NH-Z 31 -Z 32 - is. 31 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. 32 is a single bond, an ester bond, an ether bond or a sulfonamide bond. * indicates a bond to a carbon atom in the main chain.)

15. 10. The negative resist composition according to claim 9, further comprising (E) a quencher.

16. 10. The chemically amplified negative resist composition according to claim 9, further comprising (F) an organic solvent.

17. 10. A method for forming a resist pattern, comprising the steps of: forming a resist film on a substrate using the chemically amplified negative resist composition according to claim 9; irradiating the resist film with a pattern using high-energy rays; and developing the resist film irradiated with the pattern using an alkaline developer.

18. 18. The method for forming a resist pattern according to claim 17, wherein the high-energy radiation is extreme ultraviolet radiation or an electron beam.

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

20. 18. The method of forming a resist pattern according to claim 17, wherein the substrate is a transmission type or a reflection type mask blank.

21. A transmission or reflection mask blank coated with the chemically amplified negative resist composition according to claim 9.

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