Chemically amplified negative resist composition and resist pattern forming method

Abstract

To provide a chemically amplified negative resist composition which improves rectangularity during pattern formation and can give a resist pattern improved in LER, resolution, pattern fidelity and dose margin, and to provide a resist pattern forming method.SOLUTION: The chemically amplified negative resist composition contains: (A) a quencher containing an onium salt represented by the following formula (A); and (B) a base polymer containing a polymer which contains an aromatic ring-containing specific repeating unit having a hydroxyl group in a side chain.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to 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 photolithography, various improvements have been made to control sensitivity and pattern profile by changing the selection and combination of materials used in resist compositions, process conditions, etc. One of the focuses of these improvements is the problem of acid diffusion, which has a significant effect on the resolution of chemically amplified resist compositions.

[0007] The quencher suppresses acid diffusion and is a virtually essential component for improving the performance of the resist composition, particularly the resolution. Various studies have been conducted on the quencher, and amines and weak acid onium salts are generally used. As an example of a weak acid onium salt, Patent Document 4 describes that the addition of triphenylsulfonium acetate can form a good resist pattern without the formation of a T-top, the difference in line width between an isolated pattern and a dense pattern, and standing waves. Patent Document 5 describes that the addition of an ammonium sulfonate salt or an ammonium carboxylate salt improves the sensitivity, resolution, and exposure margin. Patent Document 6 describes that a resist composition for KrF lithography and EB lithography, which is a combination containing a photoacid generator that generates a fluorine atom-containing carboxylic acid, has excellent resolution and improved process tolerance such as exposure margin and depth of focus. Furthermore, Patent Document 7 also describes that a resist composition for F2 lithography using an F2 laser, which contains a photoacid generator that generates a fluorine atom-containing carboxylic acid, is excellent in line edge roughness (LER) and has an improved bottoming problem. These are used in KrF lithography, EB lithography, or F2 lithography.

[0008] Patent Document 8 describes a positive-type photosensitive composition for ArF lithography that contains a carboxylate onium salt. These compositions suppress the acid decomposition reaction of acid labile groups by replacing a strong acid (sulfonic acid) with a weak acid (carboxylic acid) by forming a weak acid and a strong acid onium salt, which replaces a strong acid (sulfonic acid) with a weak acid (carboxylic acid) by exposure to light, thereby reducing (controlling) the acid diffusion distance, and apparently functioning as a quencher.

[0009] Patent documents 9 to 11 describe nitrogen-containing heterocyclic compounds such as indole and indoline, and carboxylic acid onium salts having a piperidine carboxylic acid structure, Patent document 12 describes carboxylic acid onium salts having an aminobenzoic acid structure, and Patent document 13 describes carboxylic acid onium salts having an amide bond. Although these also act as quenchers, aromatic amines and amide bonds are not highly basic, so that the acid diffusion control ability is insufficient, and piperidine carboxylic acid is extremely water-soluble, so that there are many problems in industrial production. In addition, as for their role, they are mainly handled as quenchers for additive-type fluorinated alkanesulfonic acids, and in particular, they have not been sufficiently examined as quenchers to be used in negative resist compositions having polyhydroxystyrene as a base polymer used in the EB writing process in mask blank processing.

[0010] However, when patterning is performed using a resist composition containing the above-mentioned onium carboxylate or onium fluorocarboxylate, LER and resolution are still insufficient in recent years, despite the progress in miniaturization. Therefore, there has been a demand for the development of a quencher that can further reduce LER and improve resolution, rectangularity, pattern fidelity, and dose margin. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] JP 2006-201532 A [Patent Document 2] JP 2006-215180 A [Patent Document 3] JP 2008-249762 A [Patent Document 4] Patent No. 3955384 [Patent Document 5] Japanese Patent Application Publication No. 11-327143 [Patent Document 6] Patent No. 4231622 [Patent Document 7] Patent No. 4116340 [Patent Document 8] Patent No. 4226803 [Patent Document 9] Patent No. 6217561 [Patent Document 10] Patent No. 6874738 [Patent Document 11] Patent No. 6512049 [Patent Document 12] Patent No. 6323302 [Patent Document 13] International Publication No. 2019 / 087626 Summary of the Invention [Problem to be solved by the invention]

[0012] 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 is capable of improving rectangularity during pattern formation, and of obtaining a resist pattern that has improved LER, resolution, pattern fidelity and dose margin, and a method of forming a resist pattern. [Means for solving the problem]

[0013] Means for Solving the Problems The present inventors have conducted intensive research in order to achieve the above-mentioned object and have found that when a quencher composed of an onium salt containing an anion having a specific nitrogen-containing aliphatic heterocycle and a fluorocarboxylic acid structure is introduced into a resist composition, it is possible to obtain a pattern that exhibits good resolution and pattern shape as well as improved LER, pattern fidelity and dose margin, which has led to the completion of the present invention.

[0014] That is, the present invention provides the following chemically amplified negative resist composition and method of forming a resist pattern. 1. A chemically amplified negative resist composition comprising: (A) a quencher comprising an onium salt represented by the following formula (A); and (B) a base polymer comprising a polymer comprising a repeating unit represented by the following formula (B1). [ka] (In the formula, n1 is an integer of 0 to 6, n2 is an integer of 0 to 3, and n3 is an integer of 1 to 4. W is a nitrogen atom-containing aliphatic heterocycle having 2 to 20 carbon atoms which may contain a heteroatom. L A and L B are each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a carbonate bond or a carbamate bond. X L is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. R 1 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. When n1≧2, multiple R 1 may be bonded to each other to form a ring together with the carbon atom on W to which they are attached. Q 1 ~Q 4 are each independently a hydrogen atom, a fluorine atom, a hydrocarbyl group having 1 to 6 carbon atoms, or a fluorinated hydrocarbyl group having 1 to 6 carbon atoms, provided that Q 1 ~Q 4 At least one of Q is a fluorine atom or a fluorinated hydrocarbyl group having 1 to 6 carbon atoms. 3 and Q 4 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R AL is an acid labile group. Z + is an onium cation. [ka] (In the formula, a1 is 0 or 1. a2 is an integer of 0 to 2. a3 is an integer that satisfies 0≦a3≦5+2(a2)−a4. a4 is an integer of 1 to 3. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 11represents 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 -CH2- of the saturated hydrocarbylene group may be substituted with -O-. 2.R AL is a group represented by the following formula (AL-1) or (AL-2): [ka] (In the formula, L C is -O- or -S-. R 2 , R 3 and R 4 are each independently a hydrocarbyl group having 1 to 10 carbon atoms. 2 , R 3 and R 4 Any two of may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R 5 and R 6 R are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. 7 is a hydrocarbyl group having 1 to 20 carbon atoms, and -CH2- in the hydrocarbyl group may be substituted with -O- or -S-. 6 and R 7 and are bonded to each other and the carbon atom and L C may form a heterocyclic group having 3 to 20 carbon atoms together, and -CH2- of the heterocyclic group may be substituted with -O- or -S-. m1 and m2 each independently represent 0 or 1. * represents a bond to the adjacent -O-.) 3.Z +is a sulfonium cation represented by the following formula (cation-1), an iodonium cation represented by the following formula (cation-2), or an ammonium cation represented by the following formula (cation-3). [ka] (In the formula, R c1 ~R c9 are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. c1 and R c2 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 4. The chemically amplified negative resist composition according to any one of 1 to 3, wherein the onium salt is represented by the following formula (A1): [ka] (In the formula, n1~n3, W, L A , X L , R 1 , Q 1 ~Q 4 , R AL and Z + is the same as above.) 5. The chemically amplified negative resist composition according to 4, wherein the onium salt is represented by the following formula (A2): [ka] (In the formula, n1, W, L A , X L , R 1 , Q 1 ~Q 3 , R AL and Z + is the same as above.) 6. The chemically amplified negative resist composition according to any one of 1 to 5, wherein the polymer further contains a repeating unit represented by the following formula (B2): [ka] (In the formula, b1 is 0 or 1. b2 is an integer of 0 to 2. b3 is an integer satisfying 0≦b3≦5+2(b2)−b4. b4 is an integer of 1 to 3. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 12 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 13 and R 14 are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms which may be substituted with a hydroxy group or a saturated hydrocarbyloxy group, or an aryl group which may have a substituent. 13 and R 14 cannot be a hydrogen atom at the same time. 13 and R 14 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. A 2 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 1 is a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, or an aryl group which may have a substituent. 7. The chemically amplified negative resist composition according to any one of 1 to 6, wherein the polymer further comprises at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (B3), a repeating unit represented by the following formula (B4), and a repeating unit represented by the following formula (B5): [ka] (In the formula, c and d each independently represent an integer of 0 to 4. e1 is 0 or 1. e2 is an integer of 0 to 2. e3 is an integer of 0 to 5.) R Ais 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 halogen atom, 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 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-. 8. The chemically amplified negative resist composition of 6, wherein the polymer further comprises at least one repeating unit selected from the group consisting of a repeating unit represented by formula (B6), a repeating unit represented by formula (B7), a repeating unit represented by formula (B8), a repeating unit represented by formula (B9), a repeating unit represented by formula (B10), a repeating unit represented by formula (B11), a repeating unit represented by formula (B12), and a repeating unit represented by formula (B13). [ka] (In the formula, R B are each independently a hydrogen atom or a methyl group. Y 1 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, or *-OY 11 -, *-C(=O)-OY11 - or *-C(=O)-NH-Y 11 - and Y 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. Y 2 is a single bond or **-Y 21 -C(=O)-O-, and Y 21 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. Y 3 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, *-OY 31 -, *-C(=O)-OY 31 - or -C(=O)-NH-Y 31 -It is. Y 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. * represents a bond to a carbon atom in the main chain, and ** represents a bond to an oxygen atom in the formula. Y 4 represents a single bond or a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. f1 and f2 are each independently 0 or 1, but Y 4 When is a single bond, f1 and f2 are 0. R 31 ~R 48 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 31 and R 32 may be bonded to each other to form a ring together with the sulfur atom to which they are attached, R 33 and R 34 , R 36 and R 37, or R 39 and R 40 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. The chemically amplified negative resist composition of 8, wherein the polymer comprises a repeating unit represented by the following formula (B1-1), a repeating unit represented by the following formula (B2-1) or a repeating unit represented by the following formula (B2-2), and a repeating unit represented by the following formula (B7). [ka] (In the formula, a4, b4, R A , R B , Y 2 , R 13 , R 14 , R 33 , R 34 , R 35 and R HF is the same as above.) 10. The chemically amplified negative resist composition of 8 or 9, further comprising a polymer in which the base polymer (B) further comprises a repeating unit represented by formula (B1) and a repeating unit represented by formula (B2), and does not contain any of the repeating units represented by formulas (B6) to (B13). 11. The chemically amplified negative resist composition according to any one of 1 to 10, 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. 12. Any one of the chemically amplified negative resist compositions 1 to 11, further comprising (C) a crosslinking agent. 13. The chemically amplified negative resist composition of 6 which does not contain a crosslinking agent. 14. Any of the chemically amplified negative resist compositions according to 1 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 an integer of 1 to 3. y is an integer that satisfies 0≦y≦5+2z−x. z is 0 or 1. g is an integer of 1 to 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 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 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 110is 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 (g+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (g+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. Z 2 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * is a bond to a carbon atom in the main chain. 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. Any one of the chemically amplified negative resist compositions according to 1 to 14, further comprising (E) an acid generator. 16. The chemically amplified negative resist composition of 15, wherein the acid strength (pKa) of the anion of the acid generator is −3.0 or more. 17. The chemically amplified negative resist composition of 15 or 16, wherein the content ratio of the acid generator (E) to the quencher (A) is less than 6 by mass ratio. 18. Any one of the chemically amplified negative resist compositions according to 1 to 17, further comprising (F) an organic solvent. 19. 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 1 to 18; irradiating the resist film with a pattern using high-energy rays; and developing the resist film irradiated with the pattern using an alkaline developer. 20. The method for forming a resist pattern according to claim 19, wherein the high energy radiation is EUV or EB. 21. The method for forming a resist pattern according to claim 19 or 20, 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. 22. The method for forming a resist pattern according to any one of 19 to 21, wherein the substrate is a transmission type or a reflection type mask blank. 23. A transmission or reflection mask blank coated with any one of the chemically amplified negative resist compositions 1 to 18. Effect of the Invention

[0015] The chemically amplified negative resist composition of the present invention can effectively control acid diffusion caused by exposure during pattern formation due to the action of the onium salt represented by formula (A), and when a resist film is formed using this to form a pattern, a pattern having extremely high resolution, high pattern fidelity, and improved LER and dose margin can be obtained. In addition, due to the action of the repeating unit represented by formula (B1), the composition exhibits good solubility in an alkaline developer, and can improve adhesion to a substrate when forming a resist film.

[0016] The method of forming a resist pattern using the chemically amplified negative resist composition of the present invention is capable of forming a pattern that has high resolution and pattern fidelity while improving LER and dose margin, and therefore can be suitably used in microfabrication techniques, in particular EUV lithography and EB lithography. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The present invention will be described in detail below. In the following description, some structures represented by chemical formulas may have asymmetric carbons and may have enantiomers or diastereomers, but in such cases, one formula will be used to represent these isomers. These isomers may be used alone or as a mixture.

[0018] [Chemically amplified negative resist composition] The chemically amplified negative resist composition of the present invention is characterized by comprising (A) a quencher containing an onium salt having a specified nitrogen-containing heterocycle and a fluorocarboxylic acid structure, and (B) a base polymer containing a specified polymer.

[0019] [(A) Quencher] The quencher of the component (A) contains an onium salt represented by the following formula (A). [ka]

[0020] In formula (A), n1 is an integer of 0 to 6. n2 is an integer of 0 to 3, preferably 0 or 1. n3 is an integer of 1 to 4, preferably 1 or 2, and more preferably 1.

[0021] In formula (A), W is a nitrogen atom-containing aliphatic heterocycle having 2 to 20 carbon atoms which may contain a heteroatom. Specific examples of the structure of W include, but are not limited to, those shown below. In the following formula, * represents L A represents a bond with R, and ** represents R AL Represents a bond with -OC(=O)-. [ka]

[0022] In formula (A), L A and L B are each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate ester bond, a carbonate bond, or a carbamate bond. Among these, a single bond, an ether bond, an ester bond, or an amide bond is preferred, and a single bond, an ester bond, or an amide bond is more preferred.

[0023] In formula (A), X Lis a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbylene group may be linear, branched or cyclic, and specific examples thereof include an alkanediyl group, a cyclic saturated hydrocarbylene group, etc. Specific examples of the heteroatom include an oxygen atom, a nitrogen atom, a sulfur atom, etc.

[0024] X L Specific examples of the hydrocarbylene group having 1 to 40 carbon atoms and optionally containing a heteroatom, represented by the following formula, include, but are not limited to, those shown below. In the following formula, * represents L A and L B Represents a bond with . [ka]

[0025] [ka]

[0026] [ka]

[0027] Of these, X L -0~X L -22 and X L -47~X L -49 is preferred, X L -0~X L -17 is more preferred.

[0028] In formula (A), R 1is 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 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, an n-pentyl group, a tert-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, and 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.

[0029] Also, when n1 ≧ 2, multiple R 1may be bonded to each other to form a ring together with the carbon atom on W to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring. In addition, some or all of the hydrogen atoms in the ring 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- in the ring 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 ring may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like. In addition, two R bonded to the same atom forming W may be bonded to the same atom. 1 may be bonded to each other to form a ring, forming a spiro ring.

[0030] In formula (A), Q 1 ~Q 4 are each independently a hydrogen atom, a fluorine atom, a hydrocarbyl group having 1 to 6 carbon atoms, or a fluorinated hydrocarbyl group having 1 to 6 carbon atoms, provided that Q 1 ~Q 4 At least one of the hydrocarbyl groups is a fluorine atom or a fluorinated hydrocarbyl group having 1 to 6 carbon atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 1 Among the examples of the hydrocarbyl group having 1 to 20 carbon atoms represented by the following formula, those having 1 to 6 carbon atoms can be mentioned. As the fluorinated hydrocarbyl group having 1 to 6 carbon atoms, a trifluoromethyl group is preferable. 3 and Q 4 may be bonded to each other to form a ring together with the carbon atom to which they are bonded. Specific examples of the ring formed in this case include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a norbornane ring, and an adamantane ring.

[0031] In formula (A), R ALis an acid labile group. AL is preferably a group represented by the following formula (AL-1) or (AL-2). [ka] (In the formula, * represents a bond to the adjacent -O-.)

[0032] In formula (AL-1), R 2 , R 3 and R 4 are each independently a hydrocarbyl group having 1 to 10 carbon atoms. 2 , R 3 and R 4 Any two of may be bonded to each other to form a ring together with the carbon atoms to which they are attached. m1 is 0 or 1.

[0033] In formula (AL-2), L C is -O- or -S-. 5 and R 6 R are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. 7 is a hydrocarbyl group having 1 to 20 carbon atoms, and -CH2- in the hydrocarbyl group may be substituted with -O- or -S-. 6 and R 7 and are bonded to each other and the carbon atom and L C may form a heterocyclic group having 3 to 20 carbon atoms together, and -CH2- of the heterocyclic group may be substituted with -O- or -S-. m2 is 0 or 1.

[0034] Specific examples of the acid labile group represented by formula (AL-1) include, but are not limited to, those shown below: In the following formula, * represents a bond to the adjacent --O--. [ka]

[0035] [ka]

[0036] [ka]

[0037] [ka]

[0038] [ka]

[0039] [ka]

[0040] [ka]

[0041] [ka]

[0042] [ka]

[0043] [ka]

[0044] [ka]

[0045] Specific examples of the acid labile group represented by formula (AL-2) include, but are not limited to, those shown below: In the following formula, * represents a bond to the adjacent --O--. [ka]

[0046] [ka]

[0047] The onium salt represented by formula (A) is preferably one represented by the following formula (A1). [ka] (In the formula, n1~n3, W, L A , X L , R 1 , Q 1 ~Q 4 , R AL and Z + is the same as above.)

[0048] The onium salt represented by formula (A1) is preferably one represented by the following formula (A2). [ka] (In the formula, n1, W, L A , X L , R 1 , Q 1 ~Q 3 , R AL and Z + is the same as above.)

[0049] Specific examples of the anion of the onium salt represented by formula (A) include, but are not limited to, those shown below. [ka]

[0050] [ka]

[0051] [ka]

[0052]

change

[0053]

change

[0054]

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[0055]

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[0056]

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[0057]

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[0058]

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[0059]

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[0060]

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[0061]

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[0062]

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[0063]

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[0064]

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[0065]

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[0066]

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[0067]

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[0068]

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[0069]

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[0070]

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[0071]

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[0072]

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[0073] In formula (A), Z + is an onium cation. The onium cation is preferably a sulfonium cation represented by the following formula (cation-1), an iodonium cation represented by the following formula (cation-2), or an ammonium cation represented by the following formula (cation-3). [ka]

[0074] In formulas (cation-1)~(cation-3), R c1 ~R c9 are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom.

[0075] R c1 ~R c9 Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0076] R c1 ~R c9The hydrocarbyl group 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 30 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, and a tert-butyl group; cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, and an adamantyl group; alkenyl groups having 2 to 30 carbon atoms, such as a vinyl group, an allyl group, a propenyl group, a butenyl group, and a hexenyl group; cyclic unsaturated hydrocarbyl groups having 3 to 30 carbon atoms, such as a cyclohexenyl group; aryl groups having 6 to 30 carbon atoms, such as a phenyl group, a naphthyl group, and a thienyl group; aralkyl groups having 7 to 30 carbon atoms, such as a benzyl group, a 1-phenylethyl group, and a 2-phenylethyl group; and groups obtained by combining these, with an aryl group being preferred. 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.

[0077] Also, R c1 and R c2 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, specific examples of the sulfonium cation represented by formula (cation-1) include those represented by the following formula. [ka] (In the formula, the dashed line represents R c3 It is a bond with .)

[0078] Specific examples of the cation of the sulfonium salt represented by formula (cation-1) include, but are not limited to, those shown below. [ka]

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] [ka]

[0083] [ka]

[0084] [ka]

[0085] [ka]

[0086] [ka]

[0087] [ka]

[0088]

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[0089]

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[0090]

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[0091]

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[0092]

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[0093]

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[0094]

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[0095]

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[0096]

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[0097]

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[0098]

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[0099] [ka]

[0100] [ka]

[0101] [ka]

[0102] [ka]

[0103] [ka]

[0104] Specific examples of the iodonium cation represented by formula (cation-2) include, but are not limited to, those shown below. [ka]

[0105] [ka]

[0106] Specific examples of the ammonium cation represented by formula (cation-3) include, but are not limited to, those shown below. [ka]

[0107] Specific examples of the onium salt represented by formula (A) include any combination of the above-mentioned anions and cations.

[0108] The onium salt represented by formula (A) can be produced by a known method. As an example, a method for producing an onium salt represented by the following formula (Q-1-ex) will be described. [ka] (In the formula, n1~n3, W, L A , X L , R 1 , Q 1 ~Q 4 , R AL and Z + is the same as above. R X is a group that forms a primary or secondary ester together with the adjacent -CO2-. + is the counter cation. X - is the counter anion.)

[0109] The first step is a step of obtaining intermediate In-1-ex by reacting raw materials SM-1 and SM-2, which are commercially available or can be synthesized by a known synthesis method. When directly forming an ester bond from the carboxy group of raw material SM-1 and the hydroxy group of raw material SM-2, various condensation agents can be used. Examples of the condensation agent to be used include N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. From the viewpoint of ease of removal of the urea compound generated as a by-product after the reaction, it is preferable to use 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride. The reaction is carried out by dissolving raw materials SM-1 and SM-2 in a halogen-based solvent such as methylene chloride and adding a condensation agent. The reaction rate can be improved by adding 4-dimethylaminopyridine as a catalyst. The reaction time is usually about 12 to 24 hours, although it is desirable to follow the reaction by silica gel thin layer chromatography (TLC) to complete the reaction in terms of yield. After the reaction is stopped, the by-product urea compound is removed by filtration or washing with water as necessary, and the reaction solution is subjected to a conventional aqueous work-up to obtain intermediate In-1-ex. The obtained intermediate In-1-ex can be purified, if necessary, by conventional methods such as distillation, chromatography, and recrystallization.

[0110] The second step is a step of obtaining intermediate In-2-ex by alkaline hydrolysis of intermediate In-1-ex. Specifically, the carboxylate in intermediate In-1-ex is subjected to alkaline hydrolysis using an alkali metal hydroxide salt or a hydroxide salt of an organic cation to obtain intermediate In-2-ex, which is a carboxylate salt. Examples of the alkali metal hydroxide salt used include lithium hydroxide, sodium hydroxide, and potassium hydroxide. Examples of the hydroxide salt of an organic cation include tetramethylammonium hydroxide and benzyltrimethylammonium hydroxide. The reaction is carried out by dissolving intermediate In-1-ex in an ether solvent such as tetrahydrofuran or 1,4-dioxane, and adding an aqueous solution of various hydroxide salts. The reaction time is usually about 12 to 24 hours, although it is desirable to complete the reaction by tracking the reaction by TLC in terms of yield. The intermediate In-2-ex can be obtained by performing a normal aqueous work-up from the reaction mixture. The obtained intermediate In-2-ex can be purified according to a normal method such as chromatography or recrystallization, if necessary.

[0111] In the third step, the obtained intermediate In-2-ex is converted to Z + X - This is a process for obtaining an onium salt Q-1-ex by salt exchange with an onium salt represented by the formula: - As the anion, chloride ion, bromide ion, iodide ion, or methyl sulfate anion is preferable because the exchange reaction easily proceeds quantitatively. It is preferable to confirm the progress of the reaction by TLC in terms of yield. The onium salt Q-1-ex can be obtained by carrying out a normal aqueous work-up from the reaction mixture. If necessary, it can be purified by a normal method such as chromatography or recrystallization.

[0112] In the above scheme, the ion exchange in the third step can be easily carried out by a known method, for example, see JP-A-2007-145797.

[0113] The above-mentioned production method is merely one example, and the production method of the onium salt represented by formula (A) is not limited thereto.

[0114] The onium salt containing an anion having a nitrogen-containing aliphatic heterocycle and a fluorocarboxylic acid structure represented by formula (A) acts as a quencher, effectively trapping the strong acid generated by the acid generator in the exposed area at the aromatic carboxylate anion site, and the acid labile group protecting the nitrogen-containing aliphatic heterocycle site is deprotected by the strong acid to produce a highly basic nitrogen-containing aliphatic heterocyclic compound. The highly basic nitrogen-containing aliphatic heterocycle site suppresses excessive diffusion of acid to the unexposed area, and the carboxylate anion site continuously repeats proton exchange with the strong acid. It is believed that the synergistic effect of these improves the dissolution contrast between the exposed area and the unexposed area, and the acid diffusion of the strong acid is appropriately controlled, thereby achieving good lithography performance even in fine pattern formation. Furthermore, since the fluorocarboxylic acid structure and the acid labile group protecting the nitrogen-containing aliphatic heterocyclic moiety have an appropriate number of carbon atoms, the solubility in organic solvents is improved, and therefore penetration of an alkaline developer into exposed areas and the associated cracking of the resist pattern (top loss) can be effectively suppressed. Therefore, when applied to the chemically amplified negative resist composition of the present invention, the compound functions extremely effectively as a quencher.

[0115] In the chemically amplified negative resist composition of the present invention, the content of the quencher is preferably 0.1 to 100 parts by mass, more preferably 1 to 50 parts by mass, even more preferably 1 to 20 parts by mass, and most preferably 1 to 15 parts by mass, relative to 80 parts by mass of the (B) base polymer described below. If the content of the quencher is within the above range, the quencher functions sufficiently as a quencher, and there is no risk of performance deterioration such as a decrease in sensitivity or generation of foreign matter due to insufficient solubility. The quencher may be used alone or in combination of two or more types.

[0116] [(B) Base polymer] The base polymer of component (B) contains a polymer (hereinafter also referred to as polymer B) that contains a repeating unit represented by the following formula (B1) (hereinafter also referred to as repeating unit B1). The repeating unit B1 is a repeating unit that imparts etching resistance, adhesion to a substrate, and solubility in an alkaline developer. [ka]

[0117] In formula (B1), a1 is 0 or 1. a2 is an integer of 0 to 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. a3 is an integer that satisfies 0≦a3≦5+2(a2)-a4. a4 is an integer of 1 to 3. When a2 is 0, a3 is preferably an integer of 0 to 3 and a4 is an integer of 1 to 3, and when a2 is 1 or 2, a3 is preferably an integer of 0 to 4 and a4 is an integer of 1 to 3.

[0118] In formula (B1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0119] In formula (B1), R 11is 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 a3 is 2 or more, each R 11 may be the same as or different from each other.

[0120] In formula (B1), 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 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 a1 in formula (B1) 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 a1 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 with respect 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.

[0121] a1 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 B1 does not have -), preferred examples of the repeating unit B1 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 (B1-1) is preferred. [ka] (In the formula, R A and a4 are the same as above.)

[0122] a1 is 1 (i.e., -C(=O)-OA as a linker 1In the case where R A is the same as above. [ka]

[0123] The repeating unit B1 may be used alone or in combination of two or more kinds.

[0124] Polymer B may contain a repeating unit represented by the following formula (B2) (hereinafter, also referred to as repeating unit B2) (hereinafter, among polymers B, one further containing repeating unit B2 will also be referred to as polymer B'). [ka]

[0125] When the repeating unit B2 is irradiated with high energy rays, it converts to -OW by the action of the acid generated by the acid generator. 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 effect of the repeating unit B2 is to make the negative reaction proceed more efficiently, thereby improving the resolution.

[0126] In formula (B2), b1 is 0 or 1. b2 is an integer of 0 to 2. b3 is an integer that satisfies 0≦b3≦5+2(b2)−b4. b4 is an integer of 1 to 3.

[0127] In formula (B2), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0128] In formula (B2), R 12is 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. When b3 is 2 or more, each R 12 may be the same as or different from each other.

[0129] In formula (B2), R 13 and R 14 are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms which may be substituted with a hydroxy group or a saturated hydrocarbyloxy group, or an aryl group which may have a substituent. 13 and R 14 cannot be a hydrogen atom at the same time. 13 and R 14 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 alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, and structural isomers thereof, as well as alkyl groups in which a portion of the hydrogen atoms has been substituted with a hydroxy group or a saturated hydrocarbyloxy group.

[0130] In formula (B2), A 2is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and -CH2- of the saturated hydrocarbylene group may be replaced with -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 b1 in formula (B2) 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 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.

[0131] In formula (B2), W 1 is a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, or an aryl group which may have a substituent. The aliphatic hydrocarbyl group may be linear, branched, or cyclic, and specific examples thereof include alkyl groups such as methyl, ethyl, propyl, and isopropyl; and cyclic aliphatic hydrocarbyl groups such as cyclopentyl, cyclohexyl, and adamantyl. The aryl group may be a phenyl group. In addition, -CH2- of the aliphatic hydrocarbyl group may be substituted with -O-, -C(=O)-, -OC(=O)-, or -C(=O)-O-. The -CH2- of the hydrocarbyl group may be bonded to an oxygen atom in formula (B2). Examples of such substituted groups include a methylcarbonyl group.

[0132] The repeating unit B2 is preferably one represented by the following formula (B2-1) or (B2-2). [ka] (In the formula, b4, R A , R 13 and R 14 is the same as above.)

[0133] Preferred examples of the repeating unit B2 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]

[0134] [ka]

[0135] [ka]

[0136] [ka]

[0137] [ka]

[0138] The repeating unit B2 may be used alone or in combination of two or more kinds.

[0139] For the purpose of improving etching resistance, polymers B and B' may contain at least one repeating unit selected from the group consisting of a repeating unit represented by formula (B3) below (hereinafter also referred to as repeating unit B3), a repeating unit represented by formula (B4) below (hereinafter also referred to as repeating unit B4), and a repeating unit represented by formula (B5) below (hereinafter also referred to as repeating unit B5). [ka]

[0140] In the formulae (B3) and (B4), c and d each independently represent an integer of 0 to 4.

[0141] In formulas (B3) and (B4), 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.

[0142] In formula (B5), e1 is 0 or 1. e2 is an integer of 0 to 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.

[0143] In formula (B5), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0144] In formula (B5), R 23is a halogen atom, 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.

[0145] R 23 Preferred are halogen atoms such as fluorine, 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, methyl, ethyl, methoxy and ethoxy groups are particularly useful.

[0146] 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.

[0147] Among the above-mentioned preferable substituents, examples of useful substituents which are particularly easy to prepare as a monomer include a chlorine atom, a bromine atom, an iodine atom, a methyl group, an ethyl group, and a methoxy group.

[0148] In formula (B5), A 3is 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 f1 in formula (B5) 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 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.

[0149] e1 is 0 and A 3 is a single bond, that is, the aromatic ring is directly attached to the polymer backbone (i.e., the linker (-C(=O)-OA 3 When the repeating unit B5 does not have -), preferred examples of the repeating unit B5 include units derived from styrene, 4-chlorostyrene, 4-methylstyrene, 4-methoxystyrene, 4-bromostyrene, 4-acetoxystyrene, 2-hydroxypropylstyrene, 2-vinylnaphthalene, 3-vinylnaphthalene, etc.

[0150] Also, when e1 is 1 (i.e., -C(=O)-OA as a linker 3 Preferred examples of the repeating unit B5, when R A is the same as above. [ka]

[0151] [ka]

[0152] When at least one of the repeating units B3 to B5 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.

[0153] The repeating units B3 to B5 may be used alone or in combination of two or more.

[0154] The polymer B' may further include at least one selected from the repeating unit represented by the following formula (B6) (hereinafter also referred to as repeating unit B6), the repeating unit represented by the following formula (B7) (hereinafter also referred to as repeating unit B7), the repeating unit represented by the following formula (B8) (hereinafter also referred to as repeating unit B8), the repeating unit represented by the following formula (B9) (hereinafter also referred to as repeating unit B9), the repeating unit represented by the following formula (B10) (hereinafter also referred to as repeating unit B10), the repeating unit represented by the following formula (B11) (hereinafter also referred to as repeating unit B11), the repeating unit represented by the following formula (B12) (hereinafter also referred to as repeating unit B12), and the repeating unit represented by the following formula (B13) (hereinafter also referred to as repeating unit B13). In this case, acid diffusion can be effectively suppressed, resolution is improved, and a pattern with reduced LER can be obtained. [ka]

[0155] In formulas (B6) to (B13), R B Each of Y is independently a hydrogen atom or a methyl group. 1represents a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or *-OY 11 -, *-C(=O)-OY 11 - or *-C(=O)-NH-Y 11 - and Y 11 Y 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 is a single bond or **-Y 21 -C(=O)-O-, and Y 21 Y is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 3 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, *-OY 31 -, *-C(=O)-OY 31 - or -C(=O)-NH-Y 31 -It is. Y 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 hydroxyl group. * represents a bond to a carbon atom in the main chain, and ** represents a bond to an oxygen atom in the formula. Y 4 is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. f1 and f2 each independently represent 0 or 1, but Y 4 When is a single bond, f1 and f2 are 0.

[0156] In formulae (B6) and (B10), 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.

[0157] In formulas (B7) and (B11), Y 2 Ga-Y 21 -C(=O)-O-, Y 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.)

[0158] In formulas (B7) and (B11), R HF is a hydrogen atom or a trifluoromethyl group. In the repeating units B7 and B11, R 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 B8 and B12 when is a trifluoromethyl group include those described in JP-A-2010-77404. Examples of the repeating units B8 and B12 include those described in JP-A-2012-246265 and JP-A-2012-246426.

[0159] Preferred examples of the anion of the monomer that provides the repeating unit B9 or B13 include, but are not limited to, those shown below. [ka]

[0160] [ka]

[0161] In formulas (B6) to (B13), R 31 ~R 48are 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 of the halogen atom and hydrocarbyl group include R c1 ~R c9 Examples of the halogen atom and hydrocarbyl group represented by the formula (I) include the same as those exemplified above. 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.

[0162] Also, R 31 and R 32 may be bonded to each other to form a ring together with the sulfur atom to which they are attached, R 33 and R 34 , R 36 and R 37 , or R 39 and R 40 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, the ring formed is as described in the explanation of formula (cation-1) as R c1 and R c2 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded, similar to those exemplified above.

[0163] Specific examples of the sulfonium cations of the repeating units B7 to B9 include the same as those exemplified as the sulfonium cations represented by formula (cation-1).Specific examples of the iodonium cations of the repeating units B11 to B13 include the same as those exemplified as the iodonium cations represented by formula (cation-2).

[0164] The repeating units B6 to B13 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 thus 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.

[0165] The repeating units B6 to B13 may be used alone or in combination of two or more.

[0166] Polymers B and B' may contain a (meth)acrylic 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.

[0167] Examples of the (meth)acrylic acid ester unit having the adhesive group include a repeating unit represented by the following formula (B14) (hereinafter also referred to as repeating unit B14), a repeating unit represented by the following formula (B15) (hereinafter also referred to as repeating unit B15), and a repeating unit represented by the following formula (B16) (hereinafter also referred to as repeating unit B16). 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]

[0168] In formulas (B14) to (B16), R A R are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. 51 is -O- or a methylene group. 52 is a hydrogen atom or a hydroxyl group. 53 is a saturated hydrocarbyl group having 1 to 4 carbon atoms. k is an integer of 0 to 3. The repeating units B14 to B16 may be used alone or in combination of two or more kinds.

[0169] In the polymer B, the content of the repeating unit B1 is preferably 30 to 95 mol %, more preferably 50 to 85 mol %, in order to bring out a high contrast between the part that is negatively irradiated by high-energy radiation and the part that is not irradiated (the part that is not negatively irradiated) for the purpose of obtaining high resolution. The content of the repeating unit B2 is preferably 5 to 70 mol %, more preferably 10 to 60 mol %, in order to obtain the effect of promoting the negative reaction. The content of the repeating units B3 to B5 is preferably 0 to 30 mol %, more preferably 3 to 20 mol %, in order to obtain the effect of improving the etching resistance. Note that the polymer B may contain other repeating units in an amount of 0 to 30 mol %, preferably 0 to 20 mol %.

[0170] When polymer B' does not contain repeating units B6 to B13, the content of repeating unit B1 in polymer B' is preferably 25 to 95 mol%, more preferably 40 to 85 mol%. The content of repeating units B3 to B5 is preferably 0 to 30 mol%, more preferably 3 to 20 mol%. The content of repeating unit B5 is preferably 5 to 70 mol%, more preferably 10 to 60 mol%. Other repeating units may be contained in an amount of 0 to 30 mol%, preferably 0 to 20 mol%.

[0171] When the polymer B' contains repeating units B6 to B13, the content of the repeating unit B1 in the polymer B' is preferably 25 to 94.5 mol %, more preferably 36 to 85 mol %. The content of the repeating units B3 to B5 is preferably 0 to 30 mol %, more preferably 3 to 20 mol %. The content of the repeating unit B5 is preferably 5 to 70 mol %, more preferably 10 to 60 mol %. The total content of the repeating units B1 to B5 is preferably 60 to 99.5 mol %. The content of the repeating units B6 to B13 is preferably 0.5 to 20 mol %, more preferably 1 to 10 mol %. The polymer B' may contain other repeating units in an amount of 0 to 30 mol %, preferably 0 to 20 mol %.

[0172] Of all the repeating units constituting the polymer, the repeating units B1 to B5 preferably account for 60 mol % or more, more preferably 70 mol % or more, and even more preferably 80 mol % or more, which ensures that the properties required for the chemically amplified negative resist composition of the present invention are obtained.

[0173] In this case, polymer B' preferably contains a repeating unit represented by formula (B1-1) below, a repeating unit represented by formula (B2-1) or (B2-2) below, and a repeating unit represented by formula (B7) below. [ka] (In the formula, a4, b4, R A , R B , Y 2 , R 13 , R 14 , R 33 , R 34 , R 35 and R HF is the same as above.)

[0174] When polymer B' is used as the (B) base polymer, one not containing repeating units B6 to B13 may be used in combination with one containing repeating units B6 to B13. In this case, in the chemically amplified negative resist composition of the present invention, the content of the polymer not containing repeating units B6 to B13 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 containing repeating units B6 to B13.

[0175] When the chemically amplified negative resist composition is used to prepare a mask, the coating thickness in the most advanced generation is 150 nm or less, preferably 100 nm or less. The dissolution rate of the base polymer constituting the chemically amplified negative resist composition in an alkaline developer (e.g., a 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 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.

[0176] 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.

[0177] 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, especially 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) using tetrahydrofuran (THF) or dimethylformamide (DMF) as a solvent.

[0178] 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 has a narrow molecular weight distribution, and thus the polymer does not produce foreign matter on the pattern after development, and the pattern shape does not deteriorate.

[0179] [(C) Crosslinking agent] When the (B) base polymer does not contain polymer B', the chemically amplified negative resist composition of the present invention preferably contains a crosslinking agent as component (C). On the other hand, when the (B) base polymer contains polymer B', it does not have to contain a crosslinking agent.

[0180] Specific examples of crosslinking agents that can be used in the present invention 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.

[0181] Examples of the epoxy compound include tris(2,3-epoxypropyl)isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, and triethylolethane triglycidyl ether.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] Examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and cyclohexane diisocyanate.

[0187] Examples of the azide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0188] 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.

[0189] When the chemically amplified negative resist composition of the present invention contains a crosslinking agent (C), the content is preferably 0.1 to 50 parts by mass, more preferably 1 to 10 parts by mass, relative to 80 parts by mass of the base polymer (B). Within the above range, there is little risk of patterns being connected together and resolution decreasing. The crosslinking agent (C) may be used alone or in combination of two or more kinds.

[0190] [(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]

[0191] In the formulas (D1) to (D6), x is an integer of 1 to 3. y is an integer satisfying 0≦y≦5+2z−x. z is 0 or 1. g is an integer of 1 to 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 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 (g+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (g+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. 2 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * is a bond to a carbon atom in the main chain. 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 of the main chain.

[0192] 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.

[0193] 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.

[0194] In formula (D4), Z 1 Examples of the (g+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 g hydrogen atoms have been removed from a cyclic saturated hydrocarbyl group having 3 to 20 carbon atoms. 1Examples of the (g+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms and represented by the following formula include groups in which at least one hydrogen atom of the above-mentioned (g+1)-valent hydrocarbon group has been substituted with a fluorine atom.

[0195] 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]

[0196] [ka]

[0197] [ka]

[0198] 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.

[0199] 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.

[0200] 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.

[0201] 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]

[0202] [ka]

[0203] 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.

[0204] 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.

[0205] 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]

[0206] [ka]

[0207] [ka]

[0208] [ka]

[0209] 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.

[0210] 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.

[0211] 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.

[0212] 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.

[0213] 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 (B). The fluorine atom-containing polymer (D) may be used alone or in combination of two or more kinds.

[0214] [(E) Photoacid generator] The chemically amplified negative resist composition of the present invention may contain an acid generator as component (E). 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 upon exposure to high-energy rays. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate-type acid generators.

[0215] 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 with the (B) base polymer.

[0216] In order to obtain the effect of improving LER by combining the acid generator with a quencher of the component (A), the pKa of the acid generated from the acid 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.

[0217] As the acid generator, a salt compound having the anion shown below is preferable. [ka]

[0218] [ka]

[0219] [ka]

[0220] [ka]

[0221] [ka]

[0222] [ka]

[0223] [ka]

[0224] [ka]

[0225] Examples of the cation paired with the anion include the sulfonium cations represented by formula (cation-1) and the iodonium cations represented by formula (cation-2).

[0226] When the chemically amplified negative resist composition of the present invention contains an acid generator (E), the content 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 (B). When the base polymer contains repeating units B6 to B13 (i.e., when it is a polymer-bound acid generator), the incorporation of the acid generator (E) may be omitted. The acid generator (E) may be used alone or in combination of two or more kinds.

[0227] When the chemically amplified positive resist composition of the present invention contains a quencher, component (A), and an acid generator, component (E), the content ratio of the acid generator to the quencher ((E) / (A)) 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 positive resist composition is within the above range, acid diffusion can be sufficiently suppressed, and excellent resolution and dimensional uniformity can be obtained.

[0228] [(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, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, ethyl lactate (EL), ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol mono tert-butyl ether acetate; lactones such as γ-butyrolactone; and mixed solvents thereof.

[0229] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, PGME, cyclohexanone, EL, γ-butyrolactone, diacetone alcohol, and mixed solvents thereof are preferred.

[0230] 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.

[0231] [(G) Basic compounds] The chemically amplified negative resist composition of the present invention may contain (G) a basic compound as a quencher other than the component (A) for the purpose of correcting the shape of a pattern, etc. By adding a basic compound, acid diffusion can be effectively controlled, and even when a substrate is used whose outermost surface is made of a material containing chromium, the effect of the acid generated within the resist film on the material containing chromium can be suppressed.

[0232] Many basic compounds are known, including primary, secondary, or tertiary aliphatic amines, mixed amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, carbamates, and ammonium salts. Many specific examples of these compounds are given in Patent Document 9, but basically all of these compounds can be used. Particularly preferred compounds include tris[2-(methoxymethoxy)ethyl]amine, tris[2-(methoxymethoxy)ethyl]amine-N-oxide, dibutylaminobenzoic acid, morpholine derivatives, and imidazole derivatives.

[0233] When the chemically amplified negative resist composition of the present invention contains a basic compound (G), the content thereof is preferably 0 to 20 parts by mass, and more preferably 0 to 10 parts by mass, relative to 80 parts by mass of the base polymer (B). The basic compound (G) may be used alone or in combination of two or more kinds.

[0234] [(H) 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.

[0235] [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.

[0236] 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.

[0237] Next, the resist film is exposed to a high-energy ray to irradiate a pattern. Examples of the high-energy ray include ultraviolet rays, far ultraviolet rays, excimer laser light (KrF, ArF, etc.), EUV, X-rays, γ-rays, synchrotron radiation, EB, etc. In the present invention, it is preferable to use KrF excimer laser light, EUV, or EB for exposure.

[0238] 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 , and more preferably 100 to 400 μC / cm 2 Irradiate so that

[0239] 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.

[0240] 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.

[0241] Thereafter, the substrate is developed using a developer such as an alkaline aqueous solution of 0.1 to 5 mass %, preferably a 2 to 3 mass % TMAH aqueous solution, 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.

[0242] 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.

[0243] 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.

[0244] 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.

[0245] 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.

[0246] 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.

[0247] 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.

[0248] According to the method of forming a resist pattern of the present invention, even when a substrate (e.g., a photomask blank) is used whose outermost surface is made of a material that is likely to affect the resist pattern shape, such as a material containing chromium or silicon, the chemically amplified negative resist composition of the present invention efficiently controls acid diffusion at the substrate interface, making it possible to form a pattern that has high resolution, rectangularity, and pattern fidelity, as well as improved LER and dose margin. EXAMPLES

[0249] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0250] [1] Preparation of chemically amplified negative resist composition [Examples 1-1 to 1-50, Comparative Examples 1-1 to 1-4] Each component was dissolved in an organic solvent according to the composition shown in Tables 1 to 3 below, and each solution obtained was filtered through a UPE filter and / or a nylon filter selected from 10 nm, 5 nm, 3 nm, and 1 nm sizes to prepare chemically amplified negative resist compositions (R-1 to R-63, CR-1 to CR-8). The organic solvent was a mixed solvent of 790 parts by mass of PGMEA, 1580 parts by mass of EL, and 1580 parts by mass of PGME. In Tables 1 to 3, the crosslinker TMGU is tetramethoxymethylglycoluril, and PF-636 is a surfactant PolyFox PF-636 manufactured by OMNOVA SOLUTIONS.

[0251] [Table 1]

[0252] [Table 2]

[0253] [Table 3]

[0254] In Tables 1 to 3, polymers P-1 to P-30 are those shown in Tables 4 and 5. The Mw is a value measured in terms of polystyrene by GPC using THF or DMF as a solvent.

[0255] [Table 4]

[0256] [Table 5]

[0257] In Tables 4 and 5, the structure of each unit is as follows: [ka]

[0258] [ka]

[0259] [ka]

[0260] [ka]

[0261] [ka]

[0262] In Tables 1 to 3, quenchers Q-1 to Q-7, comparative quenchers cQ-1 to cQ-3, photoacid generators PAG-A to PAG-F, and fluorine atom-containing polymers FP-1 to FP-5 are as follows: The copolymerization composition ratio of the polymer is a molar ratio, and Mw is a polystyrene-equivalent measured value by GPC using THF or DMF as a solvent. [ka]

[0263] [ka]

[0264] [ka]

[0265] [ka]

[0266] [2] EB lithography evaluation [Examples 2-1 to 2-50, Comparative Examples 2-1 to 2-4] Each chemically amplified negative resist composition (R-1 to R-50, CR-1 to CR-4) was spin-coated using ACT-M (Tokyo Electron Ltd.) onto a mask blank consisting of a 284 nm thick Mo / Si 40-layer multilayer reflective film on a low thermal expansion glass substrate, a 3.5 nm thick Ru film as a protective film, a 70 nm thick TaN film as an absorbing layer, and a 6 nm thick CrN film as a hard mask, 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 obtained resist film was measured using an optical measuring device Nanospec (Nanometrics). Measurements were performed at 81 points on the surface of the blank substrate, excluding the outer edge portion from the outer periphery to the inside of 10 mm, and the average thickness and thickness range were calculated.

[0267] 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 110° C. for 600 seconds, and developed with a 2.38 mass % TMAH aqueous solution to obtain a negative pattern.

[0268] 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 200 nm 1:1 line and space (LS) at 1:1 was determined as the optimal exposure dose (μC / cm 2 ) and the minimum dimension at the exposure dose that resolves 200 nm LS at 1:1 was taken as the resolution (limiting resolution). For the 200 nm LS pattern obtained by irradiation at 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 variation (standard deviation, σ) was calculated and taken as the LER (nm). In addition, the CD change per 1 μC when the exposure dose that resolves 1:1 was used as the standard was calculated from the dose curve. The results are shown in Tables 6 to 8.

[0269] [Table 6]

[0270] [Table 7]

[0271] [Table 8]

[0272] The resist compositions (R-1 to R-50) of the present invention, which contain a quencher containing an onium salt represented by formula (A), effectively controlled acid diffusion and exhibited good resolution, as well as good values ​​for LER and dose margin, compared to the comparative resist compositions (CR-1 to CR-4).

[0273] In addition, the onium salt represented by formula (A) has a high quenching ability, and the amount used can be reduced to adjust the sensitivity. It is highly compatible with the solvent used and disperses uniformly in the film, so it showed particularly good LER values. Furthermore, because it has moderate liposolubility, it improves rigidity and suppresses swelling, so good resolution with excellent pattern rectangularity was obtained (CR-1 to CR-4 had a round head shape).

[0274] As described above, by using the chemically amplified negative resist composition of the present invention, a pattern with extremely high resolution and excellent LER and dose margin can be formed. 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 type or a reflection type mask blank.

Claims

1. A chemically amplified negative resist composition comprising: (A) a quencher containing an onium salt represented by the following formula (A); and (B) a base polymer containing a polymer containing a repeating unit represented by the following formula (B1). 【Chemistry 1】 (In the formula, n1 is an integer from 0 to 6, n2 is an integer from 0 to 3, and n3 is an integer from 1 to 4. W is a nitrogen atom-containing aliphatic heterocycle having 2 to 20 carbon atoms which may contain a heteroatom. L A and L B are each independently a single bond, an ether bond, an ester bond, an amide bond, a sulfonate bond, a carbonate bond or a carbamate bond. X L is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. R 1 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. When n1≧2, multiple R 1 may be bonded to each other to form a ring together with the carbon atom on W to which they are attached. Q 1 ~Q 4 are each independently a hydrogen atom, a fluorine atom, a hydrocarbyl group having 1 to 6 carbon atoms, or a fluorinated hydrocarbyl group having 1 to 6 carbon atoms. 1 ~Q 4 At least one of Q is a fluorine atom or a fluorinated hydrocarbyl group having 1 to 6 carbon atoms. 3 and Q 4 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R AL is an acid labile group. Z + is an onium cation. 【Chemistry 2】 (In the formula, a1 is 0 or 1. a2 is an integer from 0 to 2. a3 is an integer that satisfies 0≦a3≦5+2(a2)−a4. a4 is an integer from 1 to 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 - may be replaced by -O-.

2. R AL 2. The chemically amplified negative resist composition according to claim 1, wherein is a group represented by the following formula (AL-1) or (AL-2): 【Chemistry 3】 (In the formula, L C is —O— or —S—. R 2 , R 3 and R 4 are each independently a hydrocarbyl group having 1 to 10 carbon atoms. 2 , R 3 and R 4 Any two of may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R 5 and R 6 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. 7 is a hydrocarbyl group having 1 to 20 carbon atoms, and the —CH 2 - may be replaced by -O- or -S-. 6 and R 7 and are bonded to each other and the carbon atom and L C may form a heterocyclic group having 3 to 20 carbon atoms together with the heterocyclic group, and the —CH 2 - may be substituted by -O- or -S-. m1 and m2 each independently represent 0 or 1. * represents a bond to the adjacent -O-.)

3. Z + is a sulfonium cation represented by the following formula (category-1), an iodonium cation represented by the following formula (category-2), or an ammonium cation represented by the following formula (category-3). 【Chemistry 4】 (In the formula, R c1 ~R c9 are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. c1 and R c2 may be bonded to each other to form a ring together with the sulfur atom to which they are attached.)

4. 2. The chemically amplified negative resist composition according to claim 1, wherein the onium salt is represented by the following formula (A1): 【Chemistry 5】 (In the formula, n1 to n3, W, L A , X L , R 1 , Q 1 ~Q 4 , R AL and Z + is the same as above.)

5. 5. The chemically amplified negative resist composition according to claim 4, wherein the onium salt is represented by the following formula (A2): 【Chemistry 6】 (In the formula, n1, W, L A , X L , R 1 , Q 1 ~Q 3 , R AL and Z + is the same as above.)

6. 2. The chemically amplified negative resist composition according to claim 1, wherein the polymer further comprises a repeating unit represented by the following formula (B2): 【Chemistry 7】 (In the formula, b1 is 0 or 1. b2 is an integer from 0 to 2. b3 is an integer that satisfies 0≦b3≦5+2(b2)−b4. b4 is an integer from 1 to 3. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 12 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 13 and R 14 are each independently a hydrogen atom, a saturated hydrocarbyl group having 1 to 15 carbon atoms which may be substituted with a hydroxy group or a saturated hydrocarbyloxy group, or an aryl group which may have a substituent. 13 and R 14 cannot be a hydrogen atom at the same time. 13 and R 14 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. A 2 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 1 is a hydrogen atom, an aliphatic hydrocarbyl group having 1 to 10 carbon atoms, or an aryl group which may have a substituent.

7. 2. The chemically amplified negative resist composition according to claim 1, wherein the polymer further comprises at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (B3), a repeating unit represented by the following formula (B4), and a repeating unit represented by the following formula (B5): 【Chemistry 8】 (In the formula, c and d are each independently an integer of 0 to 4. e1 is 0 or 1. e2 is an integer of 0 to 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 halogen atom, 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 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-.

8. The chemically amplified negative resist composition according to claim 6, wherein the polymer further comprises at least one selected from the group consisting of a repeating unit represented by formula (B6), a repeating unit represented by formula (B7), a repeating unit represented by formula (B8), a repeating unit represented by formula (B9), a repeating unit represented by formula (B10), a repeating unit represented by formula (B11), a repeating unit represented by formula (B12), and a repeating unit represented by formula (B13): 【Chemistry 9】 (In the formula, R B are each independently a hydrogen atom or a methyl group. Y 1 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, or *-O-Y 11 -, *-C(=O)-O-Y 11 - or *-C(=O)-NH-Y 11 - and Y 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. Y 2 is a single bond or **-Y 21 -C(=O)-O-, and Y 21 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. Y 3 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-Y 31 -, *-C(=O)-O-Y 31 - or *-C(=O)-NH-Y 31 - is. 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. * represents a bond to a carbon atom in the main chain, and ** represents a bond to an oxygen atom in the formula. Y 4 is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms which may contain a heteroatom. f1 and f2 are each independently 0 or 1, 4 When is a single bond, f1 and f2 are 0. R 31 ~R 48 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 31 and R 32 may be bonded to each other to form a ring together with the sulfur atom to which they are attached, R 33 and R 34 , R 36 and R 37 , or R 39 and R 40 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. 9. The chemically amplified negative resist composition according to claim 8, wherein the polymer comprises a repeating unit represented by the following formula (B1-1), a repeating unit represented by the following formula (B2-1) or a repeating unit represented by the following formula (B2-2), and a repeating unit represented by the following formula (B7): 【Chemistry 10】 (In the formula, a4, b4, R A , R B , Y 2 , R 13 , R 14 , R 33 , R 34 , R 35 and R HF is the same as above.)

10. The chemically amplified negative resist composition according to claim 8, wherein the base polymer (B) further comprises a polymer containing a repeating unit represented by formula (B1) and a repeating unit represented by formula (B2), but not containing any of the repeating units represented by formulas (B6) to (B13).

11. 2. The chemically amplified negative resist composition according to claim 1, 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.

12. 2. The chemically amplified negative resist composition according to claim 1, further comprising (C) a crosslinking agent.

13. 7. The chemically amplified negative resist composition according to claim 6, which does not contain a crosslinking agent.

14. The chemically amplified negative resist composition according to claim 1, 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 11】 (In the formula, x is an integer of 1 to 3. y is an integer satisfying 0≦y≦5+2z−x. z is 0 or 1. g is an integer of 1 to 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 (g+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (g+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. Z 2 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * is a bond to a carbon atom in the main chain. Z 3 is a single bond, -O-, *-C(=O)-O-Z 31 -Z 32 - or *-C(=O)-NH-Z 31 -Z 32 - 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. 2. The chemically amplified negative resist composition according to claim 1, further comprising (E) an acid generator.

16. 16. The chemically amplified negative resist composition according to claim 15, wherein the acid strength (pKa) of the anion of the acid generator is -3.0 or more.

17. 16. The chemically amplified negative resist composition according to claim 15, wherein the content ratio of the acid generator (E) to the quencher (A) is less than 6 in terms of mass ratio.

18. 2. The chemically amplified negative resist composition according to claim 1, further comprising (F) an organic solvent.

19. 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 1 to 18; irradiating the resist film with a pattern using high-energy rays; and developing the resist film irradiated with the pattern using an alkaline developer.

20. 20. The method for forming a resist pattern according to claim 19, wherein the high-energy radiation is extreme ultraviolet radiation or an electron beam.

21. 20. The method for forming a resist pattern according to claim 19, 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.

22. 20. The method of forming a resist pattern according to claim 19, wherein the substrate is a transmission type or a reflection type mask blank.

23. A transmission or reflection mask blank coated with the chemically amplified negative resist composition according to any one of claims 1 to 18.

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