Chemically amplified positive resist composition and resist pattern forming method

Abstract

To provide a chemically amplified positive resist composition that can form a resist film capable of forming a pattern which has extremely high resolution, small LER, and excellent rectangularity and in which the influence of development loading and development residue defects are suppressed, and to provide a resist pattern forming method using the chemically amplified positive resist composition.SOLUTION: The chemically amplified positive resist composition contains: (A) a photoacid generator of a specific structure which generates an acid by the action of high-energy rays; and (B) a base polymer containing a polymer which increases its solubility in an alkaline aqueous solution by the action of an acid and contains a repeating unit represented by the following formula (B1).SELECTED DRAWING: None

Description

[Technical field]

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

[0002] In recent years, with the increasing integration density of integrated circuits, there is a demand for finer pattern formation, and chemically amplified resist compositions using acids as catalysts are mainly used for processing patterns of 0.2 μm or less. In addition, high-energy rays such as ultraviolet rays, far ultraviolet rays, extreme ultraviolet rays (EUV), and electron beams (EB) are used as exposure sources in this case, and 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] In EB lithography, EB writing is generally performed without using a mask. In the case of positive type, EB is sequentially irradiated on the areas other than the area to be left on the resist film, and in the case of negative type, EB is sequentially irradiated on the area to be left on the resist film. In other words, since the entire area of ​​the processing surface is finely divided, it takes more time than one-time exposure using a photomask, and a highly sensitive resist film is required to maintain throughput. In the processing of photomask blanks, which is a particularly important application, some photomask substrates have surface materials that easily affect the pattern shape of the chemically amplified resist film, such as chromium oxide and other chromium compound films formed on the photomask substrate. In order to maintain high resolution and the shape after etching, it is important to maintain the pattern profile of the resist film in a rectangular shape regardless of the type of substrate. Another important performance is to have a small line edge roughness (LER). In recent years, in order to achieve miniaturization, a multi-beam mask writing (MBMW) drawing process is sometimes used to process mask blanks. In this case, a low-sensitivity resist (high dose region) that is advantageous for roughness is used, and optimization of the resist composition in this high dose region has also come into the spotlight.

[0004] Regarding the control of sensitivity and pattern profile, various improvements have been made by the selection and combination of materials used in the resist composition, process conditions, etc. One of the improvements is the suppression of acid diffusion, which has a significant effect on the resolution of the resist film. In photomask processing, it is required that the shape of the obtained resist pattern does not change depending on the time from exposure to heating. The main cause of the time-dependent change in the resist pattern shape is the diffusion of acid generated by exposure. This problem of acid diffusion is not limited to photomask processing, but has a significant effect on the sensitivity and resolution of general resist compositions as well, and has been much studied.

[0005] Patent Documents 1 and 2 describe examples in which the acid diffusion is suppressed and LER is reduced by increasing the bulk of the acid generated from an acid generator. However, such acid generators still do not sufficiently suppress acid diffusion, so it is important to develop an acid generator with smaller acid diffusion.

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

[0007] Polymers having a large amount of aromatic skeletons with acidic side chains, such as polyhydroxystyrene, are useful as base polymers for resist compositions for KrF lithography, but have not been used as base polymers for resist compositions for ArF lithography 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 laser light, and for resist compositions for EUV lithography, because they provide high etching resistance.

[0008] As the base polymer of a positive-tone EB lithography resist composition or EUV lithography resist composition, a material is mainly used that uses an acid generated by irradiating a photoacid generator with high energy rays as a catalyst to deprotect the acid labile group masking the acidic functional group of the phenol side chain of the base polymer, thereby making it soluble in an alkaline developer. In addition, as the acid labile group, a tertiary alkyl group, a tert-butoxycarbonyl group, an acetal group, etc. have mainly been used. Here, the use of an acid labile group such as an acetal group, which requires a relatively small activation energy for deprotection, has the advantage of being able to obtain a highly sensitive resist film, but if the diffusion of the generated acid is not sufficiently suppressed, a deprotection reaction occurs even in the unexposed parts of the resist film, resulting in a problem of deterioration in resolution and LER.

[0009] On the other hand, it is known that in the development process of photomask manufacturing, a phenomenon called development loading occurs, in which the dimensional finish of the pattern differs between dense and sparse areas on the photomask. That is, development loading causes uneven distribution of the dimensional finish of the pattern depending on the surrounding pattern distribution. The causes include differences in the desorption reaction during acid generation due to the energy difference of EB, and differences in the dissolution rate in the alkaline developer of the sparse and dense pattern drawing part. As one of the improvements, Patent Document 4 discloses a method of drawing a pattern on a photomask by adjusting the incident dose in an EB drawing device and irradiating EB so as to correct the development loading. However, the conventional correction method does not take the phenomenon of development loading into sufficient consideration for correction. For this reason, the conventional correction method did not have good correction accuracy for development loading. To solve this, the drawing method when drawing a resist film described in Patent Document 5 and Patent Document 6 and the method of improving the development method after patterning have been developed, but it is insufficient to uniformly distribute sparse and dense fine patterns in the advanced generation, and an improvement in the resist composition was desired. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2009-53518 A [Patent Document 2] JP 2010-100604 A [Patent Document 3] JP 2011-22564 A [Patent Document 4] JP 2007-150243 A [Patent Document 5] Patent No. 5443548 [Patent Document 6] Patent No. 6281244 Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made in order to solve the above-mentioned problems, and has an object to provide a chemically amplified positive resist composition that is capable of forming a resist film that has extremely high resolution, small LER, and excellent rectangularity, and is capable of forming a pattern in which the effects of development loading and development residue defects are suppressed, and a method of forming a resist pattern that uses the chemically amplified positive resist composition. [Means for solving the problem]

[0012] As a result of intensive investigations in order to achieve the above-mentioned object, the inventors have found that by introducing into a resist composition a base polymer containing a repeating unit in which a phenolic hydroxy group is protected with a tertiary ether type acid labile group, and an acid generator that generates a fluorinated aromatic sulfonic acid, it is possible to obtain a pattern that exhibits good resolution, pattern shape and LER, and that is suppressed in terms of the effects of development loading and development residue defects, and have thus completed the present invention.

[0013] That is, the present invention provides the following chemically amplified positive resist composition and method of forming a resist pattern. 1. (A) a photoacid generator represented by the following formula (A) which generates an acid when exposed to high-energy rays; and (B) A base polymer containing a polymer whose solubility in an alkaline aqueous solution increases under the action of an acid, the polymer containing a repeating unit represented by the following formula (B1): A chemically amplified positive resist composition comprising: [ka] (In the formula, n1 and n2 are each independently an integer of 0 to 2. When n2=0, n3 is an integer of 1≦n3≦4, when n2=1, n3 is an integer of 1≦n3≦6, and when n2=2, n3 is an integer of 1≦n3≦8. When n2=0, n4 is an integer of 0≦n4≦3, when n2=1, n4 is an integer of 0≦n4≦5, and when n2=2, n4 is an integer of 0≦n4≦7. However, when n2=0, n3+n4 is 1≦n3+n4≦4, when n2=1, n3+n4 is 1≦n3+n4≦6, and when n2=2, n3+n4 is 1≦n3+n4≦8. When n1=0, n5 is an integer of 1≦n5≦5, when n1=1, n5 is an integer of 1≦n5≦7, and when n1=2, n5 is an integer of 1≦n5≦9. R 1 is an iodine atom or a branched or cyclic hydrocarbyl group having 3 to 20 carbon atoms which may contain a heteroatom, and at least one R 1 , L A is bonded to the carbon atom adjacent to the carbon atom to which n5 is bonded. Also, when n5 is 2 or more, multiple R 1 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R 2 are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, and when n4 is 2 or more, 2 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R F1 represents a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, or a fluorinated thioalkoxy group having 1 to 6 carbon atoms. 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. Z + is an onium cation. [ka] (In the formula, a1 is an integer of 0 to 2. a2 is an integer of 1 or 2. a3 is an integer of 1 or 2. a4 is an integer of 0 to 4. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. X 1 is a single bond or *-C(=O)-O-. * represents a bond to a carbon atom in the main chain. R AL is an acid labile group. R F2 represents a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms. R 11 represents a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom other than a fluorine atom, or a heteroatom. Also, if a2=1, -OR AL and-R F2 must be bonded to adjacent carbon atoms on the aromatic ring. Furthermore, when a2=2, two -OR AL One of them is -R F2 must be bonded to a carbon atom adjacent to the carbon atom on the aromatic ring to which is bonded.) 2. The chemically amplified positive resist composition according to 1, wherein the photoacid generator is represented by the following formula (A1): [ka] (In the formula, n1~n5, R 1 , R 2 , R F1 , L A , X L and Z + is the same as above.) 3.Z + is a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2). [ka] (In the formula, R ct1 ~R ct5 are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. ct1 and R ct2 may be bonded to each other to form a ring together with the sulfur atom to which they are attached. 4.R AL is a group represented by the following formula (AL-1) or (AL-2): [ka] (In the formula, R L1 , R L2 and R L3 are each independently a hydrocarbyl group having 1 to 12 carbon atoms, a part of -CH2- in the hydrocarbyl group may be substituted with -O- or -S-, and when the hydrocarbyl group contains an aromatic ring, a part or all of the hydrogen atoms in the aromatic ring may be substituted with a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 4 carbon atoms which may contain a halogen atom, or an alkoxy group having 1 to 4 carbon atoms which may contain a halogen atom. L1 and R L2 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R L4 and R L5 R are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. L6 is a hydrocarbyl group having 1 to 20 carbon atoms, and a part of the -CH2- in the hydrocarbyl group may be substituted with -O- or -S-. L5 and R L6 are bonded to each other and the carbon atom and X 2 may form a heterocyclic group having 3 to 20 carbon atoms together, and a part of -CH2- in the heterocyclic group may be substituted with -O- or -S-. X 2 is -O- or -S-. m1 and m2 each independently represent 0 or 1. * represents a bond to the adjacent -O-.) 5. The chemically amplified positive resist composition according to any one of 1 to 4, wherein the polymer further comprises at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (B2) and a repeating unit represented by the following formula (B3): [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. b5 is 0 or 1. c1 is an integer from 0 to 2. c2 is an integer from 0 to 2. c3 is an integer from 0 to 5. c4 is an integer from 0 to 2. R A each independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. A 1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a portion of -CH2- in the saturated hydrocarbylene group may be substituted with -O-. A 2 is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OA 21 -It is. 21 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or naphthylene group. * represents a bond to a carbon atom of the main chain. 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 hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, R13 and R 14 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R 15 each independently represents a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkoxy group having 1 to 5 carbon atoms. R 16 are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. When b4 is 1, X is an acid labile group, and when b4 is 2 or 3, X is a hydrogen atom or an acid labile group, provided that at least one of X's is an acid labile group. 6. The chemically amplified positive resist composition according to any one of 1 to 5, wherein the polymer further contains a repeating unit represented by the following formula (B4): [ka] (In the formula, d1 is an integer that satisfies 0≦d1≦5+2(d3)−d2. d2 is an integer of 1 to 3. d3 is an integer of 0 to 2. R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. Y 1 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond to a carbon atom in the main chain. A 3 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a portion of -CH2- in the saturated hydrocarbylene group may be substituted with -O-. R 21 is a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. 7. The chemically amplified positive resist composition according to any one of 1 to 6, wherein the polymer comprises at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (B5), a repeating unit represented by the following formula (B6), and a repeating unit represented by the following formula (B7): [ka] (In the formula, e is an integer of 0 to 6. f is an integer of 0 to 4. g1 is 0 or 1. g2 is an integer of 0 to 2. g3 is an integer of 0 to 5.) R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R 22 and R 23 each independently represents a hydroxy group, a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom. R 24 represents a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms, a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group or a cyano group, and when g2 is 1 or 2 it may be a hydroxy group. A 4 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of -CH2- in the saturated hydrocarbylene group may be substituted with -O-. 8. The chemically amplified positive resist composition according to any one of 1 to 7, wherein the polymer further comprises at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (B8), a repeating unit represented by the following formula (B9), a repeating unit represented by the following formula (B10), and a repeating unit represented by the following formula (B11): [ka] (In the formula, RA each independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z 1 is a single bond or a phenylene group. Z 2 teeth,* 1 -C(=O)-OZ 21 -, * 1 -C(=O)-NH-Z 21 -or* 1 -OZ 21 -It is. 21 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group.* 1 is Z 1 Represents a bond with . Z 3 each independently represents a single bond, a phenylene group, a naphthylene group, or * 2 -C(=O)-OZ 31 -It is. 31 is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group, and the aliphatic hydrocarbylene group may contain a hydroxy group, an ether bond, an ester bond, or a lactone ring. 2 represents a bond to a carbon atom in the main chain. Z 4 each independently represents a single bond, * 3 -Z 41 -C(=O)-O-, * 3 -C(=O)-NH-Z 41 -or* 3 -OZ 41 -It is. It is. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 3 is Z 3 Represents a bond with . Z 5 each independently represents a single bond, * 4 -Z 51 -C(=O)-O-, * 4 -C(=O)-NH-Z 51 -or*4 -OZ 51 -It is. 51 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 4 is Z 4 Represents a bond with . Z 6 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, * 2 -C(=O)-OZ 61 -, * 2 -C(=O)-N(H)-Z 61 -or* 2 -OZ 61 -It is. 61 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 2 represents a bond to a carbon atom in the main chain. R 31 and R 32 are each independently 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. L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate ester bond, a carbonate bond or a carbamate bond. Rf 1 and Rf 2 are each independently a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Rf 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Rf 5 and Rf 6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms.5 and Rf 6 and cannot simultaneously become hydrogen atoms. - is a non-nucleophilic counterion. A + is an onium cation. h is an integer from 0 to 3. 9. Any one of the chemically amplified positive resist compositions according to 1 to 8, further comprising an organic solvent. 10. The chemically amplified positive resist composition according to any one of 1 to 9, further comprising 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. w is an integer of 1 to 3. R B each independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R C 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 108When is a hydrocarbyl group or a fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be present between the carbon-carbon bonds. R 109 represents a hydrogen atom or a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a group containing a heteroatom interposed between the carbon-carbon bonds. R 110 is a linear or branched hydrocarbyl group having 1 to 5 carbon atoms which may have a group containing a heteroatom interposed between the carbon-carbon bonds. R 111 represents a saturated hydrocarbyl group having 1 to 20 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom, and a portion of the -CH2- in the saturated hydrocarbyl group may be substituted with an ester bond or an ether bond. W 1 is a (w+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (w+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. W 2 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. W 3 is a single bond, -O-, *-C(=O)-OW 31 -W 32 -or*-C(=O)-NH-W 31 -W 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. * indicates a bond to a carbon atom in the main chain.) 11. Any of the chemically amplified positive resist compositions according to 1 to 10, further comprising a quencher. 12. The chemically amplified positive resist composition according to any one of 1 to 11, further comprising a photoacid generator other than the photoacid generator represented by formula (A). 13. A method for forming a resist pattern, comprising the steps of forming a resist film on a substrate using the chemically amplified positive resist composition according to any one of 1 to 12, exposing the resist film to high-energy rays, and developing the exposed resist film using an alkaline developer to obtain a resist pattern. 14. The method for forming a resist pattern according to claim 13, wherein the high-energy radiation is extreme ultraviolet radiation or an electron beam. 15. The method for forming a resist pattern according to 13 or 14, 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. 16. The method for forming a resist pattern according to any one of 13 to 15, wherein the substrate is a transmission type or a reflection type mask blank. 17. A transmissive or reflective mask blank coated with any one of the chemically amplified positive resist compositions 1 to 12. Effect of the Invention

[0014] The chemically amplified positive resist composition of the present invention is capable of forming a pattern with high resolution, small LER, and excellent rectangularity with a good shape after exposure, as well as a pattern with suppressed effects of development loading, and is suitable as a resist composition for forming a resist film sensitive to high-energy rays such as ultraviolet rays, far ultraviolet rays, EB, EUV, X-rays, gamma rays, and synchrotron radiation, which are used in the processing of semiconductors, photomask blanks, etc. Furthermore, a pattern formation method using the chemically amplified positive resist composition of the present invention can form a pattern with high resolution and etching resistance, reduced LER, and a pattern with suppressed effects of development loading and development residue defects, and therefore can be suitably used in microfabrication techniques, in particular EUV lithography and EB lithography. [Brief description of the drawings]

[0015] [Figure 1] 1 is a nuclear magnetic resonance spectrum ( 1 H-NMR / DMSO-d 6 ) of the photoacid generator PAG-1 synthesized in Synthesis Example 1-1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] [Chemically amplified positive resist composition] [(A) Photoacid generator] The chemically amplified positive resist composition of the present invention contains a photoacid generator represented by the following formula (A) as the component (A). [ka]

[0017] In formula (A), n1 and n2 are each independently an integer of 0 to 2. When n2=0, n3 is an integer of 1≦n3≦4, when n2=1, n3 is an integer of 1≦n3≦6, and when n2=2, n3 is an integer of 1≦n3≦8.

[0018] In formula (A), n4 is an integer that satisfies 0≦n4≦3 when n2=0, an integer that satisfies 0≦n4≦5 when n2=1, and an integer that satisfies 0≦n4≦7 when n2=2. However, n3+n4 satisfies 1≦n3+n4≦4 when n2=0, 1≦n3+n4≦6 when n2=1, and 1≦n3+n4≦8 when n2=2.

[0019] In formula (A), n5 is an integer satisfying 1≦n5≦5 when n1=0, an integer satisfying 1≦n5≦7 when n1=1, and an integer satisfying 1≦n5≦9 when n1=2.

[0020] In formula (A), R 1 is an iodine atom or a branched or cyclic hydrocarbyl group having 3 to 20 carbon atoms which may contain a heteroatom, and at least one R 1 is the L ASpecific examples of the hydrocarbyl group include branched alkyl groups such as an isopropyl group, a sec-butyl group, a tert-butyl group, a tert-pentyl group, and a 2-ethylhexyl 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, an oxanorbornyl group, a tricyclo[5.2.1.0 2,6 ] decyl group, adamantyl group, and other aliphatic cyclic hydrocarbon groups having 3 to 20 carbon atoms; phenyl group, naphthyl group, anthracenyl group, and other aryl groups; and groups obtained by combining these groups, but are not limited thereto. 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 cyano group, a halogen atom, 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, and the like. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom or an iodine atom is preferable. When n5 is 2 or more, each R 1 may be the same as or different from each other.

[0021] Also, when n5 is 2 or more, multiple R 1 However, they may be bonded to each other to form a ring together with the carbon atom to which they are bonded. The ring is preferably a 5- to 8-membered ring.

[0022] R in formula (A) 1 Examples of the structure in which L is bonded to an aromatic ring include, but are not limited to, those shown below. In the following formula, the dashed line represents L A Represents a bond with . [ka]

[0023] [ka]

[0024] [ka]

[0025] [ka]

[0026] [ka]

[0027] [ka]

[0028] [ka]

[0029] In formula (A), R 2 are each independently 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, 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, a tert-pentyl group, an n-hexyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, or an n-decyl group; a cyclopentyl group, a cyclohexyl group, a cyclopentylmethyl group, a cyclopentylethyl group, a cyclopentylbutyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a cyclohexylbutyl group, a norbornyl group, or a tricyclo[5.2.1.0 2,6] decyl group, adamantyl group, adamantylmethyl group, and other cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms; phenyl group, naphthyl group, anthracenyl group, and other aryl groups having 6 to 20 carbon atoms. 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 cyano group, a halogen atom, 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, and the like. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom or an iodine atom is preferable. When n4 is 2 or more, each R 2 may be the same as or different from each other.

[0030] Also, when n4 is 2 or more, multiple R 2 However, they may be bonded to each other to form a ring together with the carbon atom to which they are bonded. The ring is preferably a 5- to 8-membered ring.

[0031] In formula (A), R F1 R is a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, or a fluorinated thioalkoxy group having 1 to 6 carbon atoms. F1 is preferably a fluorine atom, a trifluoromethyl group, a difluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group, a trifluoromethylthio group, or a difluoromethylthio group, and more preferably a fluorine atom, a trifluoromethyl group, or a trifluoromethoxy group. By containing a fluorine atom, the acid strength of the generated acid is improved, so that the deprotection reaction proceeds smoothly. When n3 is 2 or more, each R F1 may be the same as or different from each other.

[0032] In formula (A), L A and LB 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, an ether bond, an ester bond or a sulfonate ester bond is preferred, and an ether bond or a sulfonate ester bond is more preferred.

[0033] In formula (A), X L is 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.

[0034] 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]

[0035] [ka]

[0036] [ka]

[0037] [ka]

[0038] Of these, X L -0~X L -22 and X L -47~XL -58 is preferred.

[0039] The photoacid generator represented by formula (A) is preferably one represented by the following formula (A1). [ka] (In the formula, n1~n5, R 1 , R 2 , R F1 , L A , X L and Z + is the same as above.)

[0040] Specific examples of the anion of the photoacid generator represented by formula (A) include, but are not limited to, those shown below. [ka]

[0041] [ka]

[0042] [ka]

[0043] [ka]

[0044] [ka]

[0045] [ka]

[0046] [ka]

[0047]

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[0048]

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[0049]

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[0050]

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[0051]

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[0055]

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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] [ka]

[0069] [ka]

[0070] [ka]

[0071] [ka]

[0072] In formula (A), Z + is an onium cation. The onium cation is preferably a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2). [ka]

[0073] In formulas (cation-1) and (cation-2), R ct1 ~R ct5 are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom.

[0074] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0075] The hydrocarbyl groups 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 methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups; cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; alkenyl groups having 2 to 30 carbon atoms, such as vinyl, allyl, propenyl, butenyl, and hexenyl groups; cyclic unsaturated hydrocarbyl groups having 3 to 30 carbon atoms, such as cyclohexenyl groups; aryl groups having 6 to 30 carbon atoms, such as phenyl, naphthyl, and thienyl groups; aralkyl groups having 7 to 30 carbon atoms, such as benzyl, 1-phenylethyl, and 2-phenylethyl groups; and groups obtained by combining these, with aryl groups 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 cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, 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.

[0076] Also, R ct1 and R ct2 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. In this case, 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 ct3 It represents a bond with .)

[0077] Examples of the sulfonium cation represented by formula (cation-1) include, but are not limited to, those shown below. [ka]

[0078] [ka]

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] [ka]

[0083] [ka]

[0084] [ka]

[0085] [ka]

[0086] [ka]

[0087]

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[0088]

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[0089]

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[0090]

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[0091]

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[0093]

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[0097]

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[0098] [ka]

[0099] [ka]

[0100] [ka]

[0101] [ka]

[0102] [ka]

[0103] Examples of the iodonium cation represented by formula (cation-2) include, but are not limited to, those shown below. [ka]

[0104] [ka]

[0105] Specific examples of the onium salt monomer represented by formula (A) include any combination of the above-mentioned anions and cations.

[0106] In the chemically amplified positive resist composition of the present invention, the content of the photoacid generator (A) is preferably 0.1 to 40 parts by mass, more preferably 1 to 20 parts by mass, relative to 80 parts by mass of the base polymer (B) described below. If the content of the acid generator is within the above range, an amount of acid necessary for deprotecting the acid labile group is generated, and the storage stability is also good. The photoacid generator (A) may be used alone or in combination of two or more kinds.

[0107] [(B) Base polymer] The chemically amplified positive resist composition of the present invention contains as component (B) a base polymer which contains a polymer in which phenolic hydroxy groups are protected by acid labile groups and which becomes alkali-soluble by the action of acid.

[0108] The repeating unit in which the phenolic hydroxy group is protected by an acid labile group (hereinafter, also referred to as repeating unit B1) is represented by the following formula (B1). [ka]

[0109] In formula (B1), a1 is an integer of 0 to 2. When a1 is 0, it is a benzene ring, when a1 is 1, it is a naphthalene ring, and when a1 is 2, it is an anthracene ring, but from the viewpoint of solvent solubility, it is preferable that a1 is a benzene ring of 0. a2 is an integer of 1 or 2, but from the viewpoint of raw material procurement, it is preferable that a2 is 1. a3 is an integer of 1 or 2, but from the viewpoint of raw material procurement, it is preferable that a3 is 1. a4 is an integer of 0 to 4, but from the viewpoint of raw material procurement, it is preferable that a4 is 0 or 1.

[0110] In formula (B1), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0111] In formula (B1), X 1 is a single bond or *-C(=O)-O-. * represents a bond to a carbon atom in the main chain. X 1is preferably a single bond.

[0112] In formula (B1), R AL is an acid labile group. When a2 is 2, each R AL may be the same as or different from each other. The acid labile group is preferably a group represented by the following formula (AL-1) or (AL-2). [ka] (In the formula, * represents a bond to the adjacent oxygen atom.)

[0113] In formula (AL-1), R L1 , R L2 and R L3 are each independently a hydrocarbyl group having 1 to 12 carbon atoms, a portion of -CH2- in the hydrocarbyl group may be substituted with -O- or -S-, and when the hydrocarbyl group contains an aromatic ring, a portion or all of the hydrogen atoms in the aromatic ring may be substituted with a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 4 carbon atoms which may contain a halogen atom, or an alkoxy group having 1 to 4 carbon atoms which may contain a halogen atom.

[0114] R L1 , R L2 and R L3 The hydrocarbyl group having 1 to 12 carbon atoms represented by the formula (I) may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-undecyl and n-dodecyl groups; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, norbornylmethyl, adamantyl, adamantylmethyl, tricyclo[5.2.1.02,6 ]decyl group, tetracyclo[6.2.1.1 3,6 .0 2,7 ]Cyclic saturated hydrocarbyl groups having 3 to 12 carbon atoms, such as a dodecyl group; alkenyl groups having 2 to 12 carbon atoms, such as a vinyl group, an allyl group, a propenyl group, a butenyl group, a pentenyl group, or a hexenyl group; alkynyl groups having 2 to 12 carbon atoms, such as an ethynyl group, a propynyl group, a butynyl group, a pentynyl group, or a hexynyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 12 carbon atoms, such as a cyclopentenyl group, or a cyclohexenyl group; aryl groups having 6 to 12 carbon atoms, such as a phenyl group, a naphthyl group, or an indanyl group; aralkyl groups having 7 to 12 carbon atoms, such as a benzyl group, a 1-phenylethyl group, or a 2-phenylethyl group; and groups obtained by combining these.

[0115] Also, R L1 and R L2 may be bonded to each other to form a ring together with the carbon atom to which they are bonded. The ring formed in this case includes a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a norbornane ring, an adamantane ring, a tricyclo[5.2.1.0 2,6 ] Decane ring, tetracyclo[6.2.1.1 3,6 .0 2,7 ]dodecane ring, etc. In addition, a part of -CH2- in the ring may be substituted with -O- or -S-.

[0116] In formula (AL-2), R L4 and R L5 R are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. L4 and R L5 The hydrocarbyl group having 1 to 10 carbon atoms represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R L1 , R L2 and R L3 Among the examples of the hydrocarbyl group having 1 to 12 carbon atoms represented by the following formula, the same ones having 1 to 10 carbon atoms can be mentioned.

[0117] In formula (AL-2), R L6 is a hydrocarbyl group having 1 to 20 carbon atoms, and a part of the -CH2- in the hydrocarbyl group may be substituted with -O- or -S-. 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, 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-octyl group, an n-nonyl group, an n-decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, or an icosyl group; a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, a norbornylmethyl group, an adamantyl group, an adamantylmethyl group, or a tricyclo[5.2.1.0 2,6 ]decyl group, tetracyclo[6.2.1.1 3,6 .0 2,7 ]Cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a dodecyl group; alkenyl groups having 2 to 20 carbon atoms, such as a vinyl group, a propenyl group, a butenyl group, a pentenyl group, or a hexenyl group; alkynyl groups having 2 to 20 carbon atoms, such as an ethynyl group, a propynyl group, a butynyl group, a pentynyl group, or a hexynyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclopentenyl group, a cyclohexenyl group, or a norbornenyl group; a phenyl group, a methylphenyl group, an ethylphenyl group, an n-propylphenyl group, an isopropylphenyl group, Examples of the alkyl group include aryl groups having 6 to 20 carbon atoms, such as a p-butylphenyl group, an n-butylphenyl group, an isobutylphenyl group, a sec-butylphenyl group, a tert-butylphenyl group, a naphthyl group, a methylnaphthyl group, an ethylnaphthyl group, an n-propylnaphthyl group, an isopropylnaphthyl group, an n-butylnaphthyl group, an isobutylnaphthyl group, a sec-butylnaphthyl group, and a tert-butylnaphthyl group; aralkyl groups having 7 to 20 carbon atoms, such as a benzyl group and a phenethyl group; and groups obtained by combining these.

[0118] Also, R L5 and RL6 are bonded to each other and the carbon atom and X 2 may form a heterocyclic group having 3 to 20 carbon atoms together, and a part of -CH2- in the heterocyclic group may be substituted with -O- or -S-.

[0119] In formula (AL-2), X 2 is -O- or -S-.

[0120] In formulae (AL-1) and (AL-2), m1 and m2 each independently represent 0 or 1.

[0121] 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]

[0122] [ka]

[0123] [ka]

[0124] [ka]

[0125] [ka]

[0126] [ka]

[0127] [ka]

[0128] [ka]

[0129] [ka]

[0130] [ka]

[0131] [ka]

[0132] 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 oxygen atom. [ka]

[0133] [ka]

[0134] In formula (B1), R F2 is a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms. F2is preferably a fluorine atom, a trifluoromethyl group, a difluoromethyl group, a trifluoromethoxy group, a difluoromethoxy group, a trifluoromethylthio group, or a difluoromethylthio group, and more preferably a fluorine atom, a trifluoromethyl group, or a trifluoromethoxy group. In particular, the inclusion of a fluorine atom enables the formation of a pattern that is resistant to collapse due to the swelling suppression effect. When a3 is 2 or more, each R F2 may be the same as or different from each other.

[0135] In formula (B1), -OR AL and -R F2 Each of the groups must be bonded to adjacent carbon atoms on the aromatic ring. That is, when a2=1, -OR AL and -R F2 are bonded to adjacent carbon atoms on the aromatic ring, and when a2=2, two -OR AL At least one of the following is -R F2 is bonded to a carbon atom adjacent to the carbon atom on the aromatic ring to which -OR is bonded. AL and -R F2 are adjacent to each other, so R AL The acidity of the aromatic alcohol produced after deprotection of is increased.

[0136] In formula (B1), R 11is a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a halogen atom other than a fluorine atom, or 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, 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-octyl group, an n-nonyl group, an n-decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and an icosyl group; a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methyl Examples of the alkyl groups include cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms, such as a cyclohexyl group, a cyclohexylmethyl group, a norbornyl group, and an adamantyl group; alkenyl groups having 2 to 20 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 20 carbon atoms, such as a cyclohexenyl group; aryl groups having 2 to 20 carbon atoms, such as a phenyl group and a naphthyl group; aralkyl groups having 7 to 20 carbon atoms, such as a benzyl group, a 1-phenylethyl group, and a 2-phenylethyl group; and groups obtained by combining these groups. 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, so that the hydrocarbyl group may contain a hydroxy group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a carbonyl group, an ether bond, an ester bond, a 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. 11 may be the same as or different from each other.

[0137] Examples of monomers that provide the repeating unit B1 include, but are not limited to, those shown below. In addition, the substitution position of the substituent on the aromatic ring may be, for example, -OR ALand -R F2 However, this does not apply if R are arranged adjacent to each other. A is the same as above. [ka]

[0138] [ka]

[0139] [ka]

[0140] [ka]

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] [ka]

[0145] [ka]

[0146] [ka]

[0147]

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[0168] [ka]

[0169] [ka]

[0170] [ka]

[0171] [ka]

[0172] The polymer may further contain at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (B2) (hereinafter also referred to as repeating unit B2) and a repeating unit represented by the following formula (B3) (hereinafter also referred to as repeating unit B3). [ka]

[0173] In formula (B2), b1 is 0 or 1. b2 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. b3 is an integer that satisfies 0≦b3≦5+2(b2)-b4. b4 is an integer of 1 to 3. b5 is 0 or 1. When b2 is 0, b3 is preferably an integer of 0 to 3 and b4 is an integer of 1 to 3, and when b2 is 1 or 2, b3 is preferably an integer of 0 to 4 and b4 is an integer of 1 to 3.

[0174] In formula (B3), c1 is an integer of 0 to 2. c2 is an integer of 0 to 2. c3 is an integer of 0 to 5. c4 is an integer of 0 to 2.

[0175] In formulas (B2) and (B3), R Aeach independently represents a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0176] In formula (B2), A 1 is 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 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 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.

[0177] In formula (B3), A 2 is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-OA 21 -It is. 21 represents an aliphatic hydrocarbylene group having 1 to 20 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or naphthylene group. * represents a bond to a carbon atom of the main chain.

[0178] 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 hydrocarbyl part of the saturated hydrocarbyloxy group and saturated hydrocarbylcarbonyloxy group may be linear, branched, or cyclic, and specific examples thereof include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, pentyl, and hexyl groups; cycloalkyl groups having 3 to 6 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups; and groups obtained by combining these groups. When the number of carbon atoms is equal to or less than the upper limit, the solubility in an alkaline developer is good. When b3 is 2 or more, each R 12 may be the same as or different from each other.

[0179] In formula (B3), R 13 and R 14 are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, R 13 and R 14 may be bonded to each other to form a ring together with the carbon atoms to which they are attached.

[0180] In formula (B3), R 15 are each independently a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkoxy group having 1 to 5 carbon atoms. When c2 is 2 or more, each R 15 may be the same as or different from each other.

[0181] In formula (B3), R 16 are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. When c3 is 2 or more, each R 16 may be the same as or different from each other.

[0182] In formula (B2), X is an acid labile group when b4 is 1, and is a hydrogen atom or an acid labile group when b4 is 2 or 3, with at least one being an acid labile group. That is, in the repeating unit B2, at least one of the phenolic hydroxy groups bonded to the aromatic ring is protected with an acid labile group, or the carboxy group bonded to the aromatic ring is protected with an acid labile group. As such an acid labile group, any of those that have been used in many known chemically amplified positive resist compositions and that are cleaved by an acid to give an acidic group can be used without any particular limitation.

[0183] When a tertiary saturated hydrocarbyl group is selected as the acid labile group, it is preferable because a pattern with a small LER can be obtained even when a resist film is formed to have a thickness of, for example, 10 to 100 nm and a fine pattern with a line width of 45 nm or less is formed. The tertiary alkyl group preferably has 4 to 18 carbon atoms so that the obtained monomer for polymerization is obtained by distillation. In addition, the group bonded to the tertiary carbon atom of the tertiary saturated hydrocarbyl group may be a saturated hydrocarbyl group having 1 to 15 carbon atoms which may contain an ether bond or an oxygen atom-containing functional group such as a carbonyl group, and the groups bonded to the tertiary carbon atom may be bonded to each other to form a ring.

[0184] Specific examples of the group bonded to the tertiary carbon atom include a methyl group, an ethyl group, a propyl group, an adamantyl group, a norbornyl group, a tetrahydrofuran-2-yl group, a 7-oxanorbornan-2-yl group, a cyclopentyl group, a 2-tetrahydrofuryl group, a tricyclo[5.2.1.0 2,6 ]decyl group, tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodecyl group, and 3-oxo-1-cyclohexyl group.

[0185] Examples of tertiary saturated hydrocarbyl groups having these as substituents include tert-butyl, tert-pentyl, 1-ethyl-1-methylpropyl, 1,1-diethylpropyl, 1,1,2-trimethylpropyl, 1-adamantyl-1-methylethyl, 1-methyl-1-(2-norbornyl)ethyl, 1-methyl-1-(tetrahydrofuran-2-yl)ethyl, 1-methyl-1-(7-oxanorbornan-2-yl)ethyl, 1-methylcyclopentyl, 1-ethylcyclopentyl, 1-ethylcyclopentyl, 1-methyl ... -propylcyclopentyl group, 1-isopropylcyclopentyl group, 1-cyclopentylcyclopentyl group, 1-cyclohexylcyclopentyl group, 1-(2-tetrahydrofuryl)cyclopentyl group, 1-(7-oxanorbornan-2-yl)cyclopentyl group, 1-methylcyclohexyl group, 1-ethylcyclohexyl group, 1-cyclopentylcyclohexyl group, 1-cyclohexylcyclohexyl group, 2-methyl-2-norbornyl group, 2-ethyl-2-norbornyl group, 8-methyl-8-tricyclo[5.2.1.0 2,6 ]decyl group, 8-ethyl-8-tricyclo[5.2.1.0 2,6 ]decyl group, 3-methyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodecyl group, 3-ethyl-3-tetracyclo[4.4.0.1 2,5 .1 7,10 ]dodecyl group, 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group, 1-methyl-3-oxo-1-cyclohexyl group, 1-methyl-1-(tetrahydrofuran-2-yl)ethyl group, 5-hydroxy-2-methyl-2-adamantyl group, and 5-hydroxy-2-ethyl-2-adamantyl group.

[0186] Further, the acid labile group may be a group represented by the following formula (B2-1). The group represented by formula (B2-1) is often used as an acid labile group, and is a useful option as an acid labile group that stably gives a pattern with a relatively rectangular interface between the pattern and the substrate. When X is a group represented by formula (B2-1), an acetal structure is formed. [ka] (In the formula, the dashed lines represent bonds.)

[0187] In formula (B2-1), R L11 R is a hydrogen atom or a saturated hydrocarbyl group having 1 to 10 carbon atoms. L12 is a saturated hydrocarbyl group having a carbon number of 1 to 30. The saturated hydrocarbyl group may be linear, branched, or cyclic.

[0188] R L11 is appropriately selected depending on the design of the sensitivity of the decomposable group to acid. For example, if the design is to ensure relatively high stability and to decompose with strong acid, a hydrogen atom is selected, and if the design is to use relatively high reactivity to achieve high sensitivity to pH changes, a linear alkyl group is selected. Depending on the combination with the acid generator and basic compound to be blended in the resist composition, R L12 In the case where a relatively large alkyl group is selected at the end of the alkyl group, and the solubility change due to decomposition is large, R L11 As for R, the carbon atom bonded to the acetal carbon is preferably a secondary carbon atom. L11 Examples of the aryl group include an isopropyl group, a sec-butyl group, a cyclopentyl group, and a cyclohexyl group.

[0189] Of the acetal groups, R L12 is preferably a polycyclic alkyl group having 7 to 30 carbon atoms. L12 When R is a polycyclic alkyl group, it is preferable that a bond is formed between a secondary carbon atom constituting the polycyclic ring structure and an acetal oxygen. When the bond is formed on a secondary carbon atom of the ring structure, the polymer becomes a stable compound, and the storage stability of the resist composition is good and there is no deterioration in resolution, compared with when the bond is formed on a tertiary carbon atom. In addition, when R L12is bonded to a primary carbon atom via a linear alkyl group having one or more carbon atoms, the glass transition temperature (Tg) of the polymer is good, and the developed resist pattern does not suffer from shape defects due to baking.

[0190] Preferred examples of the group represented by formula (B2-1) include, but are not limited to, those shown below. In the following formula, R L11 is the same as above, and the dashed line represents a bond. [ka]

[0191] Preferred examples of the repeating unit B3 include, but are not limited to, those shown below. A is the same as above. [ka]

[0192] The acid labile group may be a phenolic hydroxyl group in which a hydrogen atom is substituted with -CH2COO- (a tertiary saturated hydrocarbyl group). In this case, the tertiary saturated hydrocarbyl group may be the same as the tertiary saturated hydrocarbyl group used for protecting the phenolic hydroxyl group described above.

[0193] The repeating unit B1 is preferably introduced in a range of 4 to 40 mol % of all repeating units of the polymer contained in the base polymer, and at least one selected from repeating units B2 and B3 is preferably introduced in a range of 2 to 40 mol % of all repeating units of the polymer contained in the base polymer, and the repeating units B1, B2 and B3 together are preferably introduced in a range of 8 to 60 mol %, more preferably 10 to 50 mol %, and even more preferably 10 to 40 mol % of all repeating units of the polymer contained in the base polymer.

[0194] The polymer may further include a repeating unit represented by the following formula (B4) (hereinafter also referred to as repeating unit B4). [ka]

[0195] In formula (B4), d1 is an integer that satisfies 0≦d1≦5+2(d3)−d2. d2 is an integer from 1 to 3. d3 is an integer from 0 to 2.

[0196] In formula (B4), R A is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

[0197] In formula (B4), Y 1 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond to a carbon atom in the main chain.

[0198] In formula (B4), A 3 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of -CH2- of the saturated hydrocarbylene group may be substituted with -O-. The saturated hydrocarbylene group may be linear, branched, or cyclic, and specific examples thereof include alkanediyl groups having 1 to 10 carbon atoms, such as a methylene group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, and structural isomers thereof; cyclic saturated hydrocarbylene groups having 3 to 10 carbon atoms, such as a cyclopropanediyl group, a cyclobutanediyl group, a cyclopentanediyl group, and a cyclohexanediyl group; and groups obtained by combining these.

[0199] In formula (B4), R 21is a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom. The saturated hydrocarbyl group, and the saturated hydrocarbyl carbonyloxy group and the saturated hydrocarbyloxy group may be linear, branched, or cyclic, and specific examples thereof include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, butyl, pentyl, and hexyl groups; cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl groups; 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 d1 is 2 or more, each R 21 may be the same as or different from each other.

[0200] Y 1 and A 3 When both are single bonds, preferred examples of the repeating unit B4 include units derived from 3-hydroxystyrene, 4-hydroxystyrene, 5-hydroxy-2-vinylnaphthalene, 6-hydroxy-2-vinylnaphthalene, etc. Among these, the repeating unit represented by the following formula (B4-1) is more preferred. [ka] (In the formula, R A and d2 are the same as above.)

[0201] Y 1 When R is other than a single bond, preferred examples of the repeating unit B4 include, but are not limited to, those shown below. A is the same as above. [ka]

[0202] [ka]

[0203] The repeating unit B4 is preferably introduced in the range of 10 to 95 mol %, and more preferably in the range of 30 to 85 mol %, of the total repeating units of the polymer contained in the base polymer. However, when at least one of the repeating units represented by formula (B5) and the repeating unit represented by formula (B6), which give higher etching resistance to the polymer described later, is included and the unit has a phenolic hydroxyl group as a substituent, the ratio of the unit is preferably also included within the above range. The repeating unit B4 may be used alone or in combination of two or more types.

[0204] The polymer contained in the base polymer may further contain at least one selected from the group consisting of a repeating unit represented by the following formula (B5) (hereinafter also referred to as repeating unit B5), a repeating unit represented by the following formula (B6) (hereinafter also referred to as repeating unit B6), and a repeating unit represented by the following formula (B7) (hereinafter also referred to as repeating unit B7). [ka]

[0205] In formulae (B5) and (B6), e is an integer of 0 to 6. f is an integer of 0 to 4.

[0206] In formulas (B5) and (B6), R 22 and R 23 are each independently a hydroxy group, a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom. The saturated hydrocarbylcarbonyloxy group, saturated hydrocarbyl group, and saturated hydrocarbyloxy group may be linear, branched, or cyclic. When e is 2 or more, each R 22may be the same or different. When f is 2 or more, each R 23 may be the same as or different from each other.

[0207] In formula (B7), R A is the same as above. g1 is an integer of 0 to 5. g2 is an integer of 0 to 2. g3 is an integer of 0 to 5.

[0208] In formula (B7), R 24 is an acetyl group, a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms, a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group or a cyano group, and may be a hydroxy group when g2 is 1 or 2. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, saturated hydrocarbyloxyhydrocarbyl group and saturated hydrocarbylthiohydrocarbyl group may be linear, branched or cyclic. When g3 is 2 or more, each R 24 may be the same as or different from each other.

[0209] In formula (B7), A 4 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and a part of -CH2- in the saturated hydrocarbylene group may be substituted with -O-. The saturated hydrocarbylene group may be linear, branched, or cyclic. Specific examples thereof include A in formula (B2): 1 Examples of the examples are similar to those given in the description of .

[0210] When the repeating units B5 to B7 are used, in addition to the etching resistance of the aromatic ring, the addition of a ring structure to the main chain provides the effect of improving resistance to EB irradiation during etching and pattern inspection.

[0211] In order to obtain the effect of improving etching resistance, the repeating units B5 to B7 are preferably introduced in an amount of 5 mol % or more of the total repeating units of the polymer contained in the base polymer. The repeating units B5 to B7 are preferably introduced in an amount of 30 mol % or less, more preferably 25 mol % or less of the total repeating units of the polymer contained in the base polymer. When no functional group is present or when the functional group is other than a hydroxyl group, it is preferable that the amount introduced is 30 mol % or less, since there is no risk of development defects occurring. The repeating units B5 to B7 may be used alone or in combination of two or more.

[0212] Of all the repeating units of the polymer contained in the base polymer, the content of at least one type selected from repeating unit B4 and repeating units B5 to B7 is preferably 50 mol % or more, more preferably 60 mol % or more, and even more preferably 65 mol % or more, thereby exhibiting good etching resistance, particularly in mask processing.

[0213] The polymer contained in the base polymer may further contain at least one selected from a repeating unit represented by the following formula (B8) (hereinafter also referred to as repeating unit B8), a repeating unit represented by the following formula (B9) (hereinafter also referred to as repeating unit B9), a repeating unit represented by the following formula (B10) (hereinafter also referred to as repeating unit B10), and a repeating unit represented by the following formula (B11) (hereinafter also referred to as repeating unit B11). [ka]

[0214] In formulas (B8) to (B11), R A are each independently a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. 1 is a single bond or a phenylene group. 2 teeth,* 1 -C(=O)-OZ 21 -, * 1 -C(=O)-NH-Z 21 -or*1 -OZ 21 -It is. 21 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxyl group.* 1 is Z 1 It represents a bond with Z. 3 each independently represents a single bond, a phenylene group, a naphthylene group, or * 2 -C(=O)-OZ 31 -It is. 31 is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group, and the aliphatic hydrocarbylene group may contain a hydroxy group, an ether bond, an ester bond, or a lactone ring. 2 represents a bond to a carbon atom in the main chain. Z 4 are each independently a single bond, * 3 -Z 41 -C(=O)-O-, * 3 -C(=O)-NH-Z 41 -or* 3 -OZ 41 -It is. It is. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 3 is Z 3 It represents a bond with Z. 5 each independently represents a single bond, * 4 -Z 51 -C(=O)-O-, * 4 -C(=O)-NH-Z 51 -or* 4 -OZ 51 -It is. 51 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 4 is Z 4 It represents a bond with Z. 6 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, * 2 -C(=O)-OZ 61 -, * 2-C(=O)-N(H)-Z 61 -or* 2 -OZ 61 -It is. 61 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 2 represents a bond to a carbon atom in the main chain.

[0215] Z 21 , Z 31 and Z 61 The aliphatic hydrocarbylene group 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- Examples of the alkanediyl groups include a 2,3-diyl group, a butane-1,4-diyl group, a 1,1-dimethylethane-1,2-diyl group, a pentane-1,5-diyl group, a 2-methylbutane-1,2-diyl group, and a hexane-1,6-diyl group; cycloalkanediyl groups such as a cyclopropanediyl group, a cyclobutanediyl group, a cyclopentanediyl group, and a cyclohexanediyl group; and groups obtained by combining these groups.

[0216] Z 41 and Z 51 The hydrocarbylene group represented by the formula (I) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include, but are not limited to, those shown below. [ka] (In the formula, the dashed lines represent bonds.)

[0217] In formula (B8), R 31 and R 32are each independently 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, an n-propyl group, an isopropyl group, an n-butyl group, and a tert-butyl group; cyclic saturated hydrocarbyl groups having 3 to 20 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 20 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 20 carbon atoms, such as a cyclohexenyl group; aryl groups having 6 to 20 carbon atoms, such as a phenyl group, a naphthyl group, and a thienyl group; aralkyl groups, 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 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.

[0218] 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 bonded. In this case, the ring is as defined in the description of formula (cation-1) as R ct1 and R ct2 Examples of the ring that can be formed by bonding together with the sulfur atom to which they are bonded include the same as those exemplified above.

[0219] Specific examples of the cation of the repeating unit B8 include, but are not limited to, those shown below. A is the same as above. [ka]

[0220] [ka]

[0221] [ka]

[0222] [ka]

[0223] [ka]

[0224] [ka]

[0225] [ka]

[0226] In formula (B8), M -is a non-nucleophilic counter ion. Specific examples of the non-nucleophilic counter ion include halide ions such as chloride ion and bromide ion; fluoroalkylsulfonate ions such as triflate ion, 1,1,1-trifluoroethanesulfonate ion, and nonafluorobutanesulfonate ion; arylsulfonate ions such as tosylate ion, benzenesulfonate ion, 4-fluorobenzenesulfonate ion, and 1,2,3,4,5-pentafluorobenzenesulfonate ion; alkylsulfonate ions such as mesylate ion and butanesulfonate ion; imide ions such as bis(trifluoromethylsulfonyl)imide ion, bis(perfluoroethylsulfonyl)imide ion, and bis(perfluorobutylsulfonyl)imide ion; and methide ions such as tris(trifluoromethylsulfonyl)methide ion and tris(perfluoroethylsulfonyl)methide ion.

[0227] Further, specific examples of the non-nucleophilic counter ion include a sulfonate anion represented by the following formula (B8-1) in which the α-position is substituted with a fluorine atom, and a sulfonate anion represented by the following formula (B8-2) in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group. [ka]

[0228] In formula (B8-1), R 33is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 30 carbon atoms, or a hydrocarbyloxycarbonyl group having 2 to 30 carbon atoms, and the hydrocarbyl group may contain a halogen atom, an ether bond, an ester bond, a carbonyl group, or a lactone ring. The hydrocarbyl group and the hydrocarbyl moiety of the hydrocarbylcarbonyloxy group and hydrocarbyloxycarbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 38 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a pentadecyl group, a heptadecyl group, and an icosyl group; a cyclopentyl group, a cyclohexyl group, a 1-adamantyl group, a 2-adamantyl group, and a 1-adamantylmethyl group; Examples of the alkyl group include cyclic saturated hydrocarbyl groups having 3 to 38 carbon atoms, such as a norbornyl group, a norbornylmethyl group, a tricyclodecanyl group, a tetracyclododecanyl group, a tetracyclododecanylmethyl group, and a dicyclohexylmethyl group; unsaturated aliphatic hydrocarbyl groups having 2 to 38 carbon atoms, such as an allyl group and a 3-cyclohexenyl group; aryl groups having 6 to 38 carbon atoms, such as a phenyl group, a 1-naphthyl group, and a 2-naphthyl group; aralkyl groups having 7 to 38 carbon atoms, such as a benzyl group and a diphenylmethyl group; and groups obtained by combining these groups.

[0229] In formula (B8-2), R 34 R is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbylcarbonyl group having 2 to 30 carbon atoms, and the hydrocarbyl group and the hydrocarbylcarbonyl group may contain a halogen atom, an ether bond, an ester bond, a carbonyl group, or a lactone ring. 35 is a hydrogen atom, a fluorine atom, or a fluorinated alkyl group having 1 to 6 carbon atoms. The hydrocarbyl moiety of the hydrocarbyl group and the hydrocarbyl carbonyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 33Examples of the hydrocarbyl group represented by the formula R include the same as those exemplified above. 35 As the alkyl group, a trifluoromethyl group is preferable.

[0230] Specific examples of the sulfonate anion represented by formula (B8-1) or (B8-2) include, but are not limited to, those shown below. In the following formula, R 35 is the same as above, and Ac is an acetyl group. [ka]

[0231] [ka]

[0232] [ka]

[0233] [ka]

[0234] [ka]

[0235] [ka]

[0236] [ka]

[0237] [ka]

[0238] [ka]

[0239] [ka]

[0240] Specific examples of the non-nucleophilic counter ion include non-fluorinated sulfonate anions, including, but not limited to, those shown below. [ka]

[0241] [ka]

[0242] [ka]

[0243] [ka]

[0244] [ka]

[0245] [ka]

[0246] [ka]

[0247] [ka]

[0248]

change

[0249]

change

[0250]

change

[0251]

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[0252]

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[0253]

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[0254]

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[0255]

change

[0256]

change

[0257]

change

[0258]

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[0259]

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[0260]

change

[0261]

change

[0262]

change

[0263]

change

[0264]

change

[0265]

change

[0266]

change

[0267]

change

[0268]

change

[0269]

change

[0270]

change

[0271]

change

[0272]

change

[0273]

change

[0274]

change

[0275]

change

[0276]

change

[0277]

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[0278]

change

[0279]

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[0280]

change

[0281]

change

[0282]

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[0283]

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[0284]

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[0285]

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[0286]

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[0287]

change

[0288]

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[0289]

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[0290]

change

[0291] [ka]

[0292] [ka]

[0293] [ka]

[0294] In formulas (B9) and (B10), L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate ester bond, a carbonate bond or a carbamate bond. Among these, from the viewpoint of synthesis, an ether bond, an ester bond or a carbonyl group is preferred, and an ester bond or a carbonyl group is more preferred.

[0295] In formula (B9), Rf 1 and Rf 2 are each independently a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. 1 and Rf 2 In order to increase the acid strength of the generated acid, each of Rf is preferably a fluorine atom. 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Of these, Rf 3 and Rf 4 At least one of these is preferably a trifluoromethyl group.

[0296] In formula (B9), Rf 5 and Rf 6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. 5and Rf 6 Of these, Rf 5 and Rf 6 At least one of these is preferably a trifluoromethyl group.

[0297] In the formulae (B9) and (B10), h is an integer of 0 to 3, with 1 being preferred.

[0298] Specific examples of the anion of the repeating unit B9 include, but are not limited to, those shown below. A is the same as above. [ka]

[0299] [ka]

[0300] [ka]

[0301] [ka]

[0302] [ka]

[0303] [ka]

[0304] [ka]

[0305] Specific examples of the anion of the repeating unit B10 include, but are not limited to, those shown below. A is the same as above. [ka]

[0306] [ka]

[0307] [ka]

[0308] [ka]

[0309] [ka]

[0310] [ka]

[0311] [ka]

[0312] Specific examples of the anion of the repeating unit B11 include, but are not limited to, those shown below. A is the same as above. [ka]

[0313] In formulas (B9) to (B11), A +is an onium cation. Specific examples of the onium cation include Z + Examples of the examples of the above-mentioned examples are similar to those given in the description of the above, but are not limited to these.

[0314] Among the repeating units B8 to B11, the repeating units preferred for processing the photomask blank include the repeating units B9 and B10, since they have optimal acid strength in designing the acid labile groups of the polymer.

[0315] The repeating units B8 to B11 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 shape deterioration due to unwanted film loss in the unexposed area.

[0316] The repeating units B8 to B11 are preferably introduced in an amount of 0.1 to 30 mol %, more preferably 0.5 to 20 mol %, of the total repeating units of the polymer contained in the base polymer. The repeating units B8 to B11 may be used alone or in combination of two or more.

[0317] The content of repeating units having an aromatic ring skeleton in all repeating units of the polymer contained in the base polymer is preferably 65 mol % or more, more preferably 75 mol % or more, and even more preferably 85 mol % or more. When the repeating units B8 to B11 are not contained, it is preferable that all units have an aromatic ring skeleton.

[0318] Of all the repeating units of the polymer contained in the base polymer, the content of at least one selected from repeating units B1, B2, B3, B4, and B5 to B7 is preferably 70 mol % or more, more preferably 80 mol % or more, and even more preferably 90 mol % or more.

[0319] The polymer may contain a commonly used (meth)acrylic acid ester unit protected by an acid labile group, or a (meth)acrylic acid ester unit having an adhesive group such as a lactone structure or a hydroxy group other than a phenolic hydroxy group. Although these repeating units allow fine adjustment of the properties of the resist film, they may not be included.

[0320] Examples of the (meth)acrylic acid ester unit having the adhesive group include a repeating unit represented by the following formula (B12) (hereinafter also referred to as repeating unit B12), a repeating unit represented by the following formula (B13) (hereinafter also referred to as repeating unit B13), and a repeating unit represented by the following formula (B14) (hereinafter also referred to as repeating unit B14). 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]

[0321] In formulas (B12) to (B14), R A is the same as above. 41 R is -O-, -S- or a methylene group. 42 is a hydrogen atom or a hydroxyl group. 43 is a saturated hydrocarbyl group having 1 to 4 carbon atoms. k is an integer of 0 to 3.

[0322] When the repeating units B12 to B14 are contained, the content thereof is preferably 0 to 20 mol %, more preferably 0 to 10 mol %, of the total repeating units of the polymer contained in the base polymer. The repeating units B12 to B14 may be used alone or in combination of two or more kinds.

[0323] 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, JP-A-2004-115630 can be referred to.

[0324] 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 deteriorates, especially when a pattern having a pattern line width of 100 nm or less is formed. 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.

[0325] The polymer preferably has a narrow molecular weight distribution (Mw / Mn) of 1.0 to 2.0, preferably 1.0 to 1.9, and more preferably 1.0 to 1.8. When the polymer has such a narrow molecular weight distribution, no foreign matter is generated on the pattern after development, and the shape of the pattern is not deteriorated.

[0326] In addition, as the base polymer design, the dissolution rate in an alkaline developer is preferably 10 nm / min or less, more preferably 7 nm / min or less, and even more preferably 5 nm / min or less. In the advanced generation, when the coating film on the substrate is in the thin film region (100 nm or less), the effect of pattern film loss due to alkaline development becomes large, and when the alkaline dissolution rate of the polymer is more than 10 nm / min, the pattern collapses and fine patterns cannot be formed. This is particularly noticeable in photomask production, which requires no defects, because the development process tends to be strong. In addition, in the present invention, the dissolution rate of the base polymer in an alkaline developer is a value calculated from the amount of film loss when a polymer solution (polymer concentration: 16.7 mass%, solvent: propylene glycol monomethyl ether acetate (PGMEA)) is spin-coated on an 8-inch silicon wafer, baked at 100°C for 90 seconds to form a film with a thickness of 1000 nm, and then developed at 23°C for 100 seconds with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide (TMAH).

[0327] The base polymer may include a base polymer containing a repeating unit B1, as well as a base polymer containing a known acid labile group such as a tertiary alkyl group, a tert-butoxycarbonyl group, etc. In order to exert the effects of the present invention, the proportion of the base polymer containing the repeating unit B1 among all the base polymers contained in the resist composition is preferably 30% or more.

[0328] The base polymer of the component (B) may contain other polymers other than the above-mentioned polymer. As the other polymers, those conventionally known as base polymers for resist compositions can be used. The content of the other polymers is not particularly limited as long as it does not impair the effects of the present invention.

[0329] [(C) Organic solvent] The resist composition of the present invention may contain an organic solvent as component (C). The organic solvent is not particularly limited as long as it can dissolve each component. Examples of such organic solvents include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone, as described in paragraphs

[0144] and

[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, and propylene glycol monoethyl ether. ethers such as ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as 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. When an acetal-based acid labile group is used, a high-boiling alcohol solvent, specifically diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, 1,3-butanediol, or the like, can be added to accelerate the deprotection reaction of the acetal.

[0330] Among these organic solvents, 1-ethoxy-2-propanol, PGMEA, PGME, cyclohexanone, EL, γ-butyrolactone, and mixed solvents thereof are preferable.

[0331] When the chemically amplified positive resist composition of the present invention contains an organic solvent (C), the content thereof is preferably 200 to 10,000 parts by mass, and more preferably 400 to 5,000 parts by mass, relative to 80 parts by mass of the base polymer (B). The organic solvent (C) may be used alone or in combination of two or more kinds.

[0332] [(D) Fluorine atom-containing polymer] The chemically amplified positive resist composition of the present invention, for the purposes of increasing contrast, suppressing the chemical flare phenomenon of acid when irradiated 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 the 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]

[0333] 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. w is an integer of 1 to 3. R B R are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. C 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 108each 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 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 W is a (w+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (w+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. 3 is a single bond, -O-, *-C(=O)-OW 31 -W 32 -or*-C(=O)-NH-W 31 -W 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. * represents a bond to a carbon atom in the main chain.)

[0334] 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.

[0335] 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.

[0336] In formula (D4), W 1 Examples of the (w+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 w hydrogen atoms have been further removed from a cyclic saturated hydrocarbyl group having 3 to 20 carbon atoms. 1Examples of the (w+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 (w+1)-valent hydrocarbon group has been substituted with a fluorine atom.

[0337] Specific examples of the repeating units D1 to D4 include, but are not limited to, those shown below. B is the same as above. [ka]

[0338] [ka]

[0339] [ka]

[0340] 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.

[0341] 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.

[0342] In formula (D5), W 2 is preferably *-C(=O)-O- or *-C(=O)-NH-. Cis preferably a methyl group. 2 The presence of a carbonyl group in R improves the acid trapping ability of the antistatic film. C 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.

[0343] Examples of the repeating unit D5 include, but are not limited to, those shown below. In the following formula, R C is the same as above. [ka]

[0344] [ka]

[0345] In formula (D6), W 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.

[0346] 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.

[0347] Examples of the repeating unit D6 include, but are not limited to, those shown below. In the following formula, R C is the same as above. [ka]

[0348] [ka]

[0349] [ka]

[0350] [ka]

[0351] 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.

[0352] The fluorine atom-containing polymer (D) 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 (D) contains other repeating units, the content of such units is preferably 50 mol% or less of the total repeating units of the fluorine atom-containing polymer.

[0353] (D) The fluorine atom-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.

[0354] The Mw of the fluorine atom-containing polymer (D) 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. In addition, the Mw / Mn of the fluorine atom-containing polymer (D) is preferably 1.0 to 2.2, more preferably 1.0 to 1.7.

[0355] When the chemically amplified positive 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, and more preferably 0.1 to 20 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.

[0356] [(E) Quencher] The chemically amplified positive resist composition of the present invention may contain a quencher as component (E) as necessary. In the present invention, the quencher means a compound that traps the acid generated from the acid generator. This makes it possible to suppress the diffusion speed of the acid generated from the acid generator when it diffuses into the resist film, and even when a substrate is used whose outermost surface is made of a material containing chromium, it is possible to suppress the effect of the acid generated in the resist film on the material containing chromium.

[0357] An example of a suitable quencher in the present invention is a carboxylate onium salt represented by the following formula (E1). [ka]

[0358] In formula (E1), R 201 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include an alkyl group having 1 to 40 carbon atoms, a cyclic saturated hydrocarbyl group having 3 to 40 carbon atoms, an alkenyl group having 2 to 40 carbon atoms, an alkynyl group having 2 to 40 carbon atoms, a cyclic unsaturated aliphatic hydrocarbyl group having 3 to 40 carbon atoms, an aryl group having 6 to 40 carbon atoms, an aralkyl group having 7 to 40 carbon atoms, and groups obtained by combining these groups. In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxy group, a carboxy group, a halogen atom, a cyano group, an amide group, a nitro group, a mercapto group, a sultone group, a sulfone group, or a sulfonium salt-containing group, and some of the -CH2- of the hydrocarbyl group may be substituted with an ether bond, an ester bond, a carbonyl group, a carbonate group, or a sulfonate ester bond.

[0359] In formula (E1), Mq + is an onium cation. The onium cation may be a sulfonium cation, an iodonium cation, an ammonium cation, or the like, and is preferably a sulfonium cation. Preferred sulfonium cations include those exemplified as the sulfonium cation represented by formula (cation-1).

[0360] When the chemically amplified positive resist composition of the present invention contains a carboxylate onium salt represented by formula (E1) as a quencher, the content thereof is preferably from 0.1 to 40 parts by mass, and more preferably from 0.1 to 20 parts by mass, relative to 80 parts by mass of the (B) base polymer.

[0361] Other examples of the quencher include onium carboxylates represented by the following formula (E2) or (E3). [ka] (In the formula, Mq + is the same as above.)

[0362] In formula (E2), R 211 ~R 214 Each independently represents a hydrogen atom, -L 11 -CO2 - or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 211 and R 212 And, R 212 and R 213 and, or R 213 and R 214 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. A R is a single bond or a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 115 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hydrogen atom or a heteroatom.

[0363] In formula (E2), ring R is a ring containing carbon atoms and nitrogen atoms and having 2 to 6 carbon atoms, and some or all of the hydrogen atoms bonded to the carbon atoms of the ring are hydrocarbyl groups having 1 to 20 carbon atoms, or -L 11 -CO2 - and a part of -CH2- in the ring may be substituted with a divalent group containing a sulfur atom, an oxygen atom, or a nitrogen atom. The ring may be an alicyclic ring or an aromatic ring. The ring is preferably a 5-membered or 6-membered ring, and specific examples thereof include a pyridine ring, a pyrrole ring, a pyrrolidine ring, a piperidine ring, a pyrazole ring, an imidazoline ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, an imidazoline ring, an oxazole ring, a thiazole ring, a morpholine ring, a thiazine ring, and a triazole ring.

[0364] The carboxylic acid onium salt represented by formula (E2) has at least one -L 11 -CO2 - That is, R 211 ~R 214 At least one of the following is -L11 -CO2 - and / or at least one of the hydrogen atoms bonded to the carbon atom of the ring R is -L 11 -CO2 - is replaced by

[0365] In formula (E3), R 221 ~R 226 R are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. 221 and R 222 and, or R 223 and R 226 and may be bonded to each other to form a ring together with the carbon atoms to which they are attached, R 224 and R 225 and may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded. k1 is 0 or 1. When k1=0, k2 is 0 or 1, and when k1=1, k2 is an integer of 0 to 3.

[0366] When the chemically amplified positive resist composition of the present invention contains a carboxylic acid onium salt represented by formula (E2) or (E3) as a quencher, the content thereof is preferably from 0.1 to 50 parts by mass, and more preferably from 0.5 to 30 parts by mass, relative to 80 parts by mass of the (B) base polymer.

[0367] Other examples of the quencher include sulfonium compounds represented by the following formula (E4). [ka]

[0368] In formula (E4), R 231 , R 232 and R 233are each independently a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom. A part 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 a part 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 cyano group, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonate ester bond, a carbonate bond, a carbamate bond, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, or the like. The -CH2- of the hydrocarbyl group may be a carbon atom bonded to a benzene ring in the formula.

[0369] In formula (E4), z1 and z2 each independently represent an integer of 0 to 5. z3 represents an integer of 0 to 4. z1, z2 and z3 are each preferably 0, 1 or 2 from the viewpoints of ease of synthesis and availability of raw materials.

[0370] When z1 is 2 to 5, two adjacent R 231 may be bonded to each other to form a ring together with the carbon atom to which they are bonded. When z2 is 2 to 5, two adjacent R 232 may be bonded to each other to form a ring together with the carbon atom to which they are bonded. When z3 is 2 to 4, two adjacent R 233 may be bonded to each other to form a ring together with the carbon atoms to which they are attached.

[0371] When the chemically amplified positive resist composition of the present invention contains a sulfonium compound represented by formula (E4) as a quencher, the content thereof is preferably from 0.1 to 40 parts by mass, and more preferably from 1 to 20 parts by mass, relative to 80 parts by mass of the (B) base polymer.

[0372] As the quencher, in addition to the onium salt compound described above, a photodecomposable onium salt having a nitrogen-containing substituent may be used in combination as necessary. Such a compound functions as a quencher in the unexposed area, and functions as a so-called photodecomposable base in the exposed area, which loses its quenching ability by neutralization with the acid generated from itself. By using a photodecomposable base, the contrast between the exposed area and the unexposed area can be further enhanced. Examples of the photodecomposable base include those described in JP-A-2009-109595, JP-A-2012-46501, and JP-A-2013-209360. When the chemically amplified positive resist composition of the present invention contains the photodecomposable base as a quencher, the content thereof is preferably 0.1 to 40 parts by mass, more preferably 0.1 to 20 parts by mass, relative to 80 parts by mass of the (B) base polymer.

[0373] As the quencher, an amine compound can also be used. The amine compound includes the primary, secondary, or tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, particularly amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonate ester bond. In addition, compounds in which a primary or secondary amine is protected with a carbamate group, such as the compounds described in JP-A-3790649, can also be used. When the chemically amplified positive resist composition of the present invention contains the amine compound as a quencher, the content thereof is preferably 0.001 to 12 parts by mass, more preferably 0.01 to 8 parts by mass, relative to 80 parts by mass of the (B) base polymer.

[0374] The (E) quencher may be used alone or in combination of two or more kinds.

[0375] [(F) Other photoacid generators] The chemically amplified positive resist composition of the present invention may contain a photoacid generator other than the photoacid generator represented by formula (A). The other photoacid generator is not particularly limited as long as it is a compound that generates an acid upon irradiation with high-energy rays. Suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate type photoacid generators.

[0376] Specific examples of the other photoacid generators include nonafluorobutanesulfonate, the partially fluorinated sulfonates described in JP-A-2012-189977, paragraphs

[0247] to

[0251] , the 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] .

[0377] Preferred examples of the photoacid generator include salt compounds containing anions having the structures shown below. [ka]

[0378] [ka]

[0379] [ka]

[0380] [ka]

[0381] [ka]

[0382] [ka]

[0383] [ka]

[0384] [ka]

[0385] [ka]

[0386] [ka]

[0387] Other preferred examples of the photoacid generator include salt compounds containing an anion represented by the following formula (F1). [ka]

[0388] In formula (F1), p is an integer of 1 to 3. q is an integer of 1 to 5. r is an integer of 0 to 3. s1 is 0 or 1.

[0389] In formula (F1), L 21 is a single bond, an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond or a carbamate bond.

[0390] In formula (F1), L 22 is an ether bond, an ester bond, a sulfonate ester bond, a carbonate bond or a carbamate bond.

[0391] In formula (F1), L 23represents a single bond or a hydrocarbylene group having 1 to 20 carbon atoms when p is 1, and represents a (p+1)-valent hydrocarbon group having 1 to 20 carbon atoms when p is 2 or 3, and the hydrocarbylene group and the (p+1)-valent hydrocarbon group may contain at least one bond selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxy group, and a carboxy group.

[0392] L 23 The hydrocarbylene group having 1 to 20 carbon atoms represented by the formula (1) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include a methylene group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group, and a dodecane-1,12-diyl group. Examples of the alkylene groups include alkanediyl groups having 1 to 20 carbon atoms; cyclic saturated hydrocarbylene groups having 3 to 20 carbon atoms, such as cyclopentanediyl groups, cyclohexanediyl groups, norbornanediyl groups, and adamantanediyl groups; unsaturated aliphatic hydrocarbylene groups having 2 to 20 carbon atoms, such as vinylene groups and propene-1,3-diyl groups; arylene groups having 6 to 20 carbon atoms, such as phenylene groups and naphthylene groups; and groups obtained by combining these groups. 23 The (p+1)-valent hydrocarbon group having 1 to 20 carbon atoms represented by the formula (1) may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include groups obtained by further removing one or two hydrogen atoms from the specific examples of the hydrocarbylene group having 1 to 20 carbon atoms described above.

[0393] In formula (F1), Rf 1 and Rf 2 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, provided that at least one of them is a fluorine atom or a trifluoromethyl group.

[0394] In formula (F1), R301 is a hydroxy group, a carboxy group, a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an amino group, -N(R 301A )-C(=O)-R 301B Or -N(R 301A )-C(=O)-OR 301B and R 301A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, R 301B is a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms.

[0395] R 301 , R 301A and R 301B The saturated hydrocarbyl group having 1 to 6 carbon atoms represented by the formula (I) may be linear, branched or cyclic, and specific examples thereof include alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl and n-hexyl groups; and cyclic saturated hydrocarbyl groups having 3 to 6 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl groups. 301 Examples of the saturated hydrocarbyl moiety of the saturated hydrocarbyloxy group having 1 to 6 carbon atoms represented by the formula (I) include the same as the specific examples of the saturated hydrocarbyl group described above, and R 301 Examples of the saturated hydrocarbyl moiety of the saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms represented by the following formula include those having 1 to 5 carbon atoms among the specific examples of the saturated hydrocarbyl groups having 1 to 6 carbon atoms mentioned above.

[0396] R 301BThe unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms represented by the formula (I) may be linear, branched, or cyclic, and specific examples thereof include alkenyl groups having 2 to 8 carbon atoms, such as a vinyl group, a propenyl group, a butenyl group, or a hexenyl group; alkynyl groups having 2 to 8 carbon atoms, such as an ethynyl group, a propynyl group, or a butynyl group; and cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 8 carbon atoms, such as a cyclohexenyl group or a norbornenyl group.

[0397] In formula (F1), R 302 represents a saturated hydrocarbylene group having 1 to 20 carbon atoms or an arylene group having 6 to 14 carbon atoms, some or all of the hydrogen atoms of the saturated hydrocarbylene group may be substituted with halogen atoms other than fluorine atoms, and some or all of the hydrogen atoms of the arylene group may be substituted with a substituent selected from a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms, a halogen atom, and a hydroxy group.

[0398] R 302 The saturated hydrocarbylene group having 1 to 20 carbon atoms represented by the formula (I) may be linear, branched or cyclic, and specific examples thereof include alkanediyl groups having 1 to 20 carbon atoms, such as a methylene group, an ethane-1,1-diyl group, an ethane-1,2-diyl group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, a hexane-1,6-diyl group, a heptane-1,7-diyl group, an octane-1,8-diyl group, a nonane-1,9-diyl group, a decane-1,10-diyl group, an undecane-1,11-diyl group or a dodecane-1,12-diyl group; and cyclic saturated hydrocarbylene groups having 3 to 20 carbon atoms, such as a cyclopentanediyl group, a cyclohexanediyl group, a norbornanediyl group or an adamantanediyl group.

[0399] R 302Specific examples of the arylene group having 6 to 14 carbon atoms represented by the following formula include a phenylene group, a naphthylene group, a phenanthrenediyl group, and an anthracenediyl group. The hydrocarbyl moiety of the saturated hydrocarbyl group having 1 to 20 carbon atoms and the hydrocarbyloxy group having 1 to 20 carbon atoms, which are substituents of the arylene group, may be any one of linear, branched, and cyclic, and specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, and an icosyl group; and cyclic saturated hydrocarbyl groups having 3 to 20 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. Specific examples of the arylene group having 6 to 14 carbon atoms which is the substituent of the arylene group include a phenylene group, a naphthylene group, a phenanthrenediyl group, and an anthracenediyl group.

[0400] The anion represented by formula (F1) is preferably an anion represented by the following formula (F2). [ka]

[0401] In formula (F2), p, q, r, L 21 , L 23 and R 301 is the same as above. s2 is an integer of 1 to 4. R 302A is a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms, a halogen atom, or a hydroxy group. 302A may be the same as or different from each other.

[0402] Examples of the anion represented by formula (F1) include, but are not limited to, those shown below. [ka]

[0403] [ka]

[0404] [ka]

[0405] [ka]

[0406] [ka]

[0407] [ka]

[0408] [ka]

[0409] [ka]

[0410] [ka]

[0411] [ka]

[0412]

change

[0413]

change

[0414]

change

[0415]

change

[0416]

change

[0417]

change

[0418]

change

[0419]

change

[0420]

change

[0421]

change

[0422]

change

[0423] [ka]

[0424] [ka]

[0425] [ka]

[0426] [ka]

[0427] [ka]

[0428] [ka]

[0429] [ka]

[0430] (F) In other photoacid generators, the cation paired with the above-mentioned anion is preferably a sulfonium cation or an iodonium cation.Specific examples of the sulfonium cation include, but are not limited to, the same as those exemplified as the sulfonium cation represented by formula (cation-1).Specific examples of the iodonium cation include, but are not limited to, the same as those exemplified as the sulfonium cation represented by formula (cation-2).

[0431] The acid generated by the other photoacid generator preferably has a pKa of -2.0 or more, more preferably -1.0 or more. The upper limit of the pKa is preferably 2.0. The pKa value is calculated using the pKa DB in the software ACD / Chemsketch ver:9.04 manufactured by Advanced Chemistry Development, Inc.

[0432] When the chemically amplified positive resist composition of the present invention contains (F) other photoacid generator, the content thereof is preferably 1 to 10 parts by mass, more preferably 1 to 5 parts by mass, relative to 80 parts by mass of the base polymer. (F) other photoacid generator may be used alone or in combination of two or more. By containing the other photoacid generator, the amount of acid generated in the exposed area and the dissolution inhibition property in the unexposed area can be appropriately adjusted.

[0433] [(G) Surfactant] The chemically amplified positive resist composition of the present invention may contain a commonly used surfactant as component (G) in order to improve the coating properties onto a substrate. Many of the surfactants are known as described in International Publication No. 2006 / 121096, JP-A No. 2008-102383, JP-A No. 2008-304590, JP-A No. 2004-115630, and JP-A No. 2005-8766, and the surfactant can be selected with reference to these.

[0434] When the chemically amplified positive resist composition of the present invention contains a (G) surfactant, the content thereof is preferably 2 parts by mass or less, and more preferably 1 part by mass or less, relative to 80 parts by mass of the (B) base polymer, and the lower limit thereof is preferably 0.01 parts by mass or more.

[0435] [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 positive 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 that has been irradiated with the pattern using an alkaline developer.

[0436] 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 positive 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 pre-baked 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.

[0437] Next, the resist film is exposed to a high-energy ray to irradiate a pattern. Examples of the high-energy ray include ultraviolet ray, far ultraviolet ray, excimer laser light (KrF, ArF, etc.), EUV, X-ray, γ-ray, synchrotron radiation, EB, etc. In the present invention, it is preferable to use EUV or EB for exposure.

[0438] When ultraviolet rays, far ultraviolet rays, excimer laser light, EUV, X-rays, gamma rays or synchrotron radiation is used as the high energy rays, a mask for forming a desired pattern is used and the exposure dose is preferably 1 to 500 mJ / cm. 2 , more preferably 10 to 400 mJ / cm 2 When EB is used, the exposure dose is preferably 1 to 500 μC / cm 2 directly to form the desired pattern. 2 , more preferably 10 to 400 μC / cm 2 Irradiate so that

[0439] 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.

[0440] Next, post-exposure baking (PEB) is performed on a hot plate, preferably at 60 to 150° C. for 1 to 20 minutes, and more preferably at 80 to 140° C. for 1 to 10 minutes.

[0441] Thereafter, the substrate is developed using a developer of an alkaline aqueous solution of 0.1 to 5 mass %, preferably 2 to 3 mass %, TMAH or the like, for preferably 0.1 to 3 minutes, more preferably 0.5 to 2 minutes, by a conventional method such as a dip method, a puddle method or a spray method, to form a desired pattern on the substrate.

[0442] The chemically amplified positive 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 positive 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 because 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 positive 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.

[0443] 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.

[0444] 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.

[0445] When a light-shielding film having an anti-reflection layer and a light-shielding layer is formed using a chromium-based material, the layers may be laminated in the order of an anti-reflection layer and a light-shielding layer from the surface side, or the anti-reflection layer, a light-shielding layer, and an anti-reflection layer. 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 carbonitride, chromium oxynitride, etc. may be used.

[0446] 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.

[0447] 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.

[0448] According to the method for forming a resist pattern of the present invention, even when a substrate (e.g., a transmissive or reflective mask 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, silicon or tantalum, it is possible to obtain a high-resolution pattern with small dimensional difference that is independent of pattern density and in which the effects of development loading and development residue defects are suppressed. EXAMPLES

[0449] The present invention will be specifically described below with reference to Synthesis Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples. The apparatuses used are as follows. IR: Thermo Fisher Scientific NICOLET 6700 · 1 H-NMR: ECA-500 manufactured by JEOL Ltd. MALDI TOF-MS: JEOL S3000

[0450] [1] Synthesis of photoacid generator [Example 1-1] Synthesis of photoacid generator PAG-1 [ka]

[0451] Under a nitrogen atmosphere, SM-2 (8.5 g) was suspended in a mixed solvent of THF (40 g) and water (40 g). 25% by mass sodium hydroxide aqueous solution (3.3 g) was added dropwise thereto, and the mixture was stirred at room temperature for 2 hours to dissolve SM-2. Then, SM-1 (8.5 g) was added as a powder, and the mixture was aged at room temperature for 10 hours. After aging, the reaction solution was cooled, and water (80 g) was added to stop the reaction. The target product was extracted with methylene chloride (160 g), and the target product was subjected to a normal aqueous work-up. After the solvent was distilled off, the product was recrystallized with diisopropyl ether to obtain 16.9 g of photoacid generator PAG-1 (yield 86%).

[0452] The IR spectrum data and TOF-MS results of PAG-1 are shown below. The nuclear magnetic resonance spectrum (1 The results of H-NMR / DMSO-d6) are shown in Figure 1. IR(D-ATR): ν= 3070, 2973, 2927, 2853, 1634, 1598, 1561, 1483, 1468, 1446, 1390,1378, 1365, 1356, 1327, 1272, 1260, 1237, 1225, 1189, 1166, 1129, 1111, 1073, 1050, 1008, 999, 981, 889, 864, 842, 815, 777, 768, 758, 748, 736, 682, 630, 580, 562, 534, 501, 485 cm -1 . MALDI TOF-MS: POSITIVE M + 277(C 18 H 13 OS + equivalent) NEGATIVE M - 631(C 30 H 35 F4O6S2 - equivalent)

[0453] [Examples 1-2 to 1-7] Synthesis of PAG-2 to PAG-7 Photoacid generators PAG-4 to PAG-7 represented by the following formulas were synthesized using corresponding raw materials and known organic synthesis reactions. [ka]

[0454] [2] Synthesis of monomer [Synthesis Example 2-1] Synthesis of Monomer a1-1 [ka]

[0455] (1) Synthesis of intermediate Pre-a1-1 Under a nitrogen atmosphere, sodium hydride (purity 55% by mass, 144.0 g) was suspended in THF (800 mL), and a solution consisting of 1-isopropylcyclopentanol (465.4 g) and THF (380 mL) was added dropwise. After the dropwise addition, the mixture was heated under reflux for 4 hours to prepare a metal alkoxide. Then, the raw material M-1 (854.7 g) was added dropwise, and the mixture was heated under reflux and aged for 18 hours. The reaction solution was cooled in an ice bath, and the reaction was stopped with water (1200 mL). The target product was extracted with a solvent consisting of toluene (1000 mL) and hexane (1000 mL), and the target product was subjected to normal aqueous work-up. After the solvent was distilled off, the product was purified by distillation to obtain 816.2 g of intermediate Pre-a1-1 as a colorless oil (yield 67%).

[0456] (2) Synthesis of Monomer a1-1 A Grignard reagent was prepared from magnesium (56.7 g), THF (900 g) and intermediate Pre-a1 (816.2 g) under a nitrogen atmosphere. The reaction system was diluted with toluene (450 g) and cooled to 10°C or less. Then, [1,3-bis(diphenylphosphino)propane]nickel(II) dichloride (6.0 g) was added and the reaction system was stirred at a temperature of 10°C or less for 30 minutes. After stirring, a solution consisting of vinyl bromide (260.3 g), THF (450 g) and toluene (450 g) was added dropwise while maintaining the temperature of the reaction system at 20°C or less. After the dropwise addition, the reaction system was aged for 1 hour at a temperature of 20°C or less. After aging, the reaction system was cooled and an aqueous solution consisting of ammonium chloride (233 g), 20% by mass hydrochloric acid (233 g) and water (1165 g) was added dropwise to stop the reaction. Thereafter, the target substance was extracted with hexane (2000 g), subjected to a normal aqueous work-up, and after the solvent was distilled off, the product was purified by distillation to obtain 519.5 g of monomer a1-1 as a colorless oil (yield 74%).

[0457] IR spectrum data and nuclear magnetic resonance spectrum of monomer a1-1 ( 1 The results of H-NMR / DMSO-d6) are shown below. IR(D-ATR): ν= 2966, 2877, 1597, 1584, 1504, 1470, 1454, 1417, 1391, 1369, 1352, 1253, 1225, 1201, 1167, 1122, 1033, 984, 911, 868, 831, 800, 752, 699, 627cm -1 . 1 H-NMR (600MHz in DMSO-d6): δ= 7.27(1H, d), 7.18(1H, d), 7.13(1H, d), 6.74(1H, dd), 5.80(1H, d), 5.29(1H, d), 2.47(2H, m), 1.87(4H, m), 1.54(4H, m), 0.90(6H, d) ppm.

[0458] [Synthesis Examples 2-2 to 2-7] Synthesis of Monomers a1-2 to a1-7 Monomers a1-2 to a1-7 shown below were synthesized using the corresponding raw materials and various organic synthesis reactions. [ka]

[0459] [3] Synthesis of base polymer The structure of the repeating unit introduced into the polymer is shown below. [ka]

[0460] [ka]

[0461] [ka]

[0462] [ka]

[0463] [ka]

[0464] [ka]

[0465] [Synthesis Example 3-1] Synthesis of Polymer P-1 Under a nitrogen atmosphere, 52.9 g of 4-acetoxystyrene, 39.4 g of monomer a1-1, 7.6 g of acenaphthylene, 7.4 g of dimethyl-2,2'-azobis-(2-methylpropionate) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product name V601), and 139 g of methyl ethyl ketone as a solvent were added to a 300 mL dropping cylinder to prepare a solution. Further, 62 g of methyl ethyl ketone was added to another 500 mL polymerization flask under a nitrogen atmosphere, and the solution was dropped over 4 hours while being heated to 80 ° C. After the dropwise addition, the polymerization temperature was maintained at 80 ° C. and stirring was continued for 18 hours, and then cooled to room temperature. The obtained polymerization solution was dropped into 1000 g of hexane, and the precipitated copolymer was filtered off. The filtered copolymer was washed twice with 500 g of hexane. The obtained copolymer was dissolved in a mixed solvent of 150 g of tetrahydrofuran and 50 g of methanol in a 1 L flask under a nitrogen atmosphere, 22.3 g of ethanolamine was added, and the mixture was stirred at 60 ° C. for 3 hours. The reaction solution was concentrated under reduced pressure, and the obtained concentrate was dissolved in a mixed solvent of 240 g of ethyl acetate and 60 g of water, and the obtained solution was transferred to a separatory funnel, 11.1 g of acetic acid was added, and a separation operation was performed. The lower layer was removed, and 60 g of water and 14.8 g of pyridine were added to the obtained organic layer, and a separation operation was performed. The lower layer was removed, and 60 g of water was added to the obtained organic layer to perform water washing and separation (water washing and separation were performed a total of 5 times). The organic layer after separation was concentrated and then dissolved in 130 g of acetone. The obtained acetone solution was added dropwise to 1200 g of water to obtain a crystallized precipitate, which was then filtered and washed with water. After suction filtration for 2 hours, the filtered product was again dissolved in 130 g of acetone, and the obtained acetone solution was added dropwise to 1200 g of water to obtain a precipitate, which was then filtered, washed with water and dried to obtain 56.3 g of the target polymer P-1, which is a white polymer. Polymer P-1 was 13 C-NMR, 1 Measurement by H-NMR and GPC gave the following analytical results: [ka]

[0466] [Synthesis Examples 3-2 to 3-30, Comparative Synthesis Examples 1-1 to 1-15] Synthesis of polymers P-2 to P-30 and comparative polymers CP-1 to CP-15 The following polymers P-2 to P-30 were synthesized with reference to Example 3-1 and known methods, except that the types and compounding ratios of each monomer were changed.

[0467] [Table 1]

[0468] [Table 2]

[0469] [Table 3]

[0470] [4] Preparation of chemically amplified positive resist composition [Examples 1-1 to 1-50, Comparative Examples 1-1 to 1-21] Chemically amplified positive resist compositions were prepared by dissolving each component in an organic solvent according to the compositions shown in Tables 4 to 7 below, and filtering the resulting solution through a 5 nm nylon filter and a 1 nm UPE filter. The organic solvent was a mixed solvent of 940 parts by mass of PGMEA, 1870 parts by mass of EL, and 1870 parts by mass of PGME.

[0471] [Table 4]

[0472] [Table 5]

[0473] [Table 6]

[0474] [Table 7]

[0475] In Tables 4 to 7, the structures of the comparative photoacid generators cPAG-1 to cPAG-4, the photoacid generators PAG-A and PAG-B, the quenchers Q-1 to Q-4, and the fluorine atom-containing polymers D-1 to D-5 are as follows. [ka]

[0476] [ka]

[0477] [ka]

[0478] [ka]

[0479] [4] EB lithography evaluation [Examples 2-1 to 2-50, Comparative Examples 2-1 to 2-32] Each chemically amplified positive resist composition (R-1 to R-50, CR-1 to CR-32) was spin-coated using ACT-M (Tokyo Electron Ltd.) onto a reflective mask blank for EUV exposure masks, which was a 6-inch-side low-thermal expansion glass substrate with a 284-nm-thick Mo / Si 40-layer multilayer reflective film, 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. The mask blank was prebaked 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 instrument 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 by 10 mm, and the average thickness and thickness range were calculated.

[0480] Furthermore, the resist 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 positive pattern.

[0481] 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 a 200 nm isolated space at a ratio of 9:1 was taken as the resolution (limit IS resolution), and the LER of 200 nm LS was measured using an SEM. For the development loading evaluation, the exposure dose (μC / cm) that resolves a 1:1 LS of the design 200 nm at a ratio of 1:1 was used within the substrate surface. 2 The space dimensions of a 200nm LS pattern formed by the 200nm LS pattern with dummy patterns of densities of 15%, 25%, 33%, 45%, 50%, 55%, 66%, 75%, 85%, and 95% were measured by SEM, and the dimensional differences of the dense and sparse patterns were compared. The pattern shape was visually judged to be rectangular or not.

[0482] The dissolution rate of the exposed area was measured by spin-coating a resist solution onto an 8-inch silicon wafer, baking it at 110°C for 60 seconds to form a resist film with a thickness of 90 nm, and then measuring the exposure dose (mJ / cm2) required to resolve a 1:1 line and space (LS) of 200 nm at 1:1. 2 ) and exposed to KrF excimer laser light, baked at 110°C for 60 seconds, and then developed at 23°C with a 2.38% by mass TMAH aqueous solution using a resist development analyzer (RDA-800 manufactured by LithoTech Japan Co., Ltd.), and calculations were performed. The results are shown in Tables 8 to 10.

[0483] [Table 8]

[0484] [Table 9]

[0485] [Table 10]

[0486] The results shown in Tables 8 to 10 demonstrate that the chemically amplified positive resist composition and method of forming a resist pattern of the present invention are useful for semiconductor device production, particularly photolithography in the processing of transmission and reflective photomask blanks.

Claims

1. (A) a photoacid generator represented by the following formula (A) that generates an acid when exposed to high-energy rays; and (B) A base polymer containing a polymer whose solubility in an alkaline aqueous solution increases under the action of an acid, the polymer containing a repeating unit represented by the following formula (B1): A chemically amplified positive resist composition comprising: 【Chemical 1】 (In the formula, n1 and n2 are each independently an integer of 0 to 2. When n2=0, n3 is an integer of 1≦n3≦4, when n2=1, n3 is an integer of 1≦n3≦6, and when n2=2, n3 is an integer of 1≦n3≦8. When n2=0, n4 is an integer of 0≦n4≦3, when n2=1, n4 is an integer of 0≦n4≦5, and when n2=2, n4 is an integer of 0≦n4≦7. However, when n2=0, n3+n4 satisfies 1≦n3+n4≦4, when n2=1, n3+n4≦6, and when n2=2, n3+n4≦8. When n1=0, n5 is an integer of 1≦n5≦5, when n1=1, n5 is an integer of 1≦n5≦7, and when n1=2, n5 is an integer of 1≦n5≦9. R 1 is an iodine atom or a branched or cyclic hydrocarbyl group having 3 to 20 carbon atoms which may contain a heteroatom, and at least one R 1 Is, L A When n5 is 2 or more, a plurality of R 1 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R 2 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a heteroatom, and when n4 is 2 or more, a plurality of R 2 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R F1 is a fluorine atom, a fluorinated alkyl group having 1 to 6 carbon atoms, a fluorinated alkoxy group having 1 to 6 carbon atoms, or a fluorinated thioalkoxy group having 1 to 6 carbon atoms. 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. X L is a single bond or a hydrocarbylene group having 1 to 40 carbon atoms which may contain a heteroatom. Z + is an onium cation. 【Chemistry 2】 (In the formula, a1 is an integer of 0 to 2, a2 ​​is an integer of 1 or 2, a3 is an integer of 1 or 2, and a4 is an integer of 0 to 4. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. X 1 is a single bond or *-C(=O)-O-. * represents a bond to a carbon atom in the main chain. R AL is an acid labile group. R F2 is a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 6 carbon atoms, or a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms. R 11 is a hydrocarbyl group having 1 to 20 carbon atoms which may contain a halogen atom other than a fluorine atom or a heteroatom. Also, when a2=1, -O-R AL and-R F2 must be bonded to adjacent carbon atoms on the aromatic ring. AL One of them is -R F2 It must be bonded to a carbon atom adjacent to the carbon atom on the aromatic ring to which is bonded.)

2. 2. The chemically amplified positive resist composition according to claim 1, wherein the photoacid generator is represented by the following formula (A1): 【Chemistry 3】 (In the formula, n1 to n5, R 1 , R 2 , R F1 , L A , X L and Z + is the same as above.)

3. Z + 2. The chemically amplified positive resist composition according to claim 1, wherein is a sulfonium cation represented by the following formula (cation-1) or an iodonium cation represented by the following formula (cation-2): 【Chemistry 4】 (In the formula, R ct1 ~R ct5 are each independently a halogen atom or a hydrocarbyl group having 1 to 30 carbon atoms which may contain a heteroatom. ct1 and R ct2 may be bonded to each other to form a ring together with the sulfur atom to which they are attached.)

4. R AL 2. The chemically amplified positive resist composition according to claim 1, wherein is a group represented by the following formula (AL-1) or (AL-2): 【Chemistry 5】 (In the formula, R L1 , R L2 and R L3 are each independently a hydrocarbyl group having 1 to 12 carbon atoms, and the —CH 2 A part of - may be substituted with -O- or -S-, and when the hydrocarbyl group contains an aromatic ring, a part or all of the hydrogen atoms of the aromatic ring may be substituted with a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 4 carbon atoms which may contain a halogen atom, or an alkoxy group having 1 to 4 carbon atoms which may contain a halogen atom. L1 and R L2 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R L4 and R L5 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. L6 is a hydrocarbyl group having 1 to 20 carbon atoms, and the —CH 2 A part of - may be substituted with -O- or -S-. L5 and R L6 are bonded to each other and the carbon atoms and X 2 may form a heterocyclic group having 3 to 20 carbon atoms together with the —CH 2 A portion of - may be substituted with -O- or -S-. X 2 is —O— or —S—. m1 and m2 each independently represent 0 or 1. * represents a bond to the adjacent —O—.)

5. 2. The chemically amplified positive 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 (B2) and a repeating unit represented by the following formula (B3): 【Chemistry 6】 (In the formula, 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. b5 is 0 or 1. c1 is an integer from 0 to 2. c2 is an integer from 0 to 2. c3 is an integer from 0 to 5. c4 is an integer from 0 to 2. R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. A 1 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and the —CH 2 A part of - may be substituted with -O-. A 2 is a single bond, a phenylene group, a naphthylene group, or *-C(=O)-O-A 21 - is. A 21 is an aliphatic hydrocarbylene group having 1 to 20 carbon atoms which may contain a hydroxy group, an ether bond, an ester bond or a lactone ring, or a phenylene group or naphthylene group. * represents a bond to a carbon atom in the main chain. 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 hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom, and R 13 and R 14 may be bonded to each other to form a ring together with the carbon atoms to which they are attached. R 15 are each independently a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, or a fluorinated alkoxy group having 1 to 5 carbon atoms. R 16 are each independently a hydrocarbyl group having 1 to 10 carbon atoms which may contain a heteroatom. When b4 is 1, X is an acid labile group, and when b4 is 2 or 3, X is a hydrogen atom or an acid labile group, provided that at least one X is an acid labile group.

6. 2. The chemically amplified positive resist composition according to claim 1, wherein the polymer further comprises a repeating unit represented by the following formula (B4): 【Chemistry 7】 (In the formula, d1 is an integer that satisfies 0≦d1≦5+2(d3)−d2. d2 is an integer from 1 to 3. d3 is an integer from 0 to 2. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Y 1 is a single bond, *-C(=O)-O-, or *-C(=O)-NH-. * represents a bond to a carbon atom in the main chain. A 3 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and the —CH 2 A part of - may be substituted with -O-. R 21 is a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 6 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 6 carbon atoms which may be substituted with a halogen atom.

7. 2. The chemically amplified positive resist composition according to claim 1, wherein the polymer comprises at least one repeating unit selected from the group consisting of a repeating unit represented by the following formula (B5), a repeating unit represented by the following formula (B6), and a repeating unit represented by the following formula (B7): 【Chemistry 8】 (In the formula, e is an integer of 0 to 6, f is an integer of 0 to 4, g1 is 0 or 1, g2 is an integer of 0 to 2, and g3 is an integer of 0 to 5. R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R 22 and R 23 are each independently a hydroxy group, a halogen atom, a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, a saturated hydrocarbyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, or a saturated hydrocarbyloxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom. R 24 represents a saturated hydrocarbyl group having 1 to 20 carbon atoms, a saturated hydrocarbyloxy group having 1 to 20 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a saturated hydrocarbyloxyhydrocarbyl group having 2 to 20 carbon atoms, a saturated hydrocarbylthiohydrocarbyl group having 2 to 20 carbon atoms, a halogen atom, a nitro group or a cyano group, and when g2 is 1 or 2 it may be a hydroxy group. A 4 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms, and the —CH 2 A part of - may be replaced by -O-.)

8. 2. The chemically amplified positive 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 (B8), a repeating unit represented by the following formula (B9), a repeating unit represented by the following formula (B10), and a repeating unit represented by the following formula (B11): 【Chemistry 9】 (In the formula, R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z 1 is a single bond or a phenylene group. Z 2 teeth,* 1 -C(=O)-O-Z 21 -, * 1 -C(=O)-NH-Z 21 -or* 1 -O-Z 21 - is. Z 21 represents an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, or a divalent group obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 1 Is Z 1 Represents a bond with . Z 3 are each independently a single bond, a phenylene group, a naphthylene group, or * 2 -C(=O)-O-Z 31 - is. Z 31 is an aliphatic hydrocarbylene group having 1 to 10 carbon atoms, a phenylene group, or a naphthylene group, and the aliphatic hydrocarbylene group may contain a hydroxy group, an ether bond, an ester bond, or a lactone ring. 2 represents a bond to a carbon atom in the main chain. Z 4 are each independently a single bond, * 3 -Z 41 -C(=O)-O-, * 3 -C(=O)-NH-Z 41 -or* 3 -O-Z 41 -It is. It is. Z 41 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 3 Is Z 3 Represents a bond with . Z 5 are each independently a single bond, * 4 -Z 51 -C(=O)-O-, * 4 -C(=O)-NH-Z 51 -or* 4 -O-Z 51 - is. Z 51 is a hydrocarbylene group having 1 to 20 carbon atoms which may contain a heteroatom. 4 Is Z 4 Represents a bond with . Z 6 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, * 2 -C(=O)-O-Z 61 -, * 2 -C(=O)-N(H)-Z 61 -or* 2 -O-Z 61 - is. Z 61 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. 2 represents a bond to a carbon atom in the main chain. R 31 and R 32 are each independently 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. L 1 is a single bond, an ether bond, an ester bond, a carbonyl group, a sulfonate ester bond, a carbonate bond or a carbamate bond. Rf 1 and Rf 2 are each independently a fluorine atom or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Rf 3 and Rf 4 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. Rf 5 and Rf 6 are each independently a hydrogen atom, a fluorine atom, or a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms. 5 and Rf 6 and cannot simultaneously become hydrogen atoms. - is a non-nucleophilic counterion. A + is an onium cation. h is an integer from 0 to 3.

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

10. 2. The chemically amplified positive resist composition according to claim 1, further comprising a fluorine atom-containing polymer that 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 that 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 10】 (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. w is an integer of 1 to 3.) R B are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R C 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 bond. R 109 is 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 its 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 interposed 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 —CH 2 A portion of the - may be substituted with an ester bond or an ether bond. W 1 is a (w+1)-valent hydrocarbon group having 1 to 20 carbon atoms or a (w+1)-valent fluorinated hydrocarbon group having 1 to 20 carbon atoms. W 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. W 3 is a single bond, -O-, *-C(=O)-O-W 31 -W 32 - or *-C(=O)-NH-W 31 -W 32 - is. W 31 is a single bond or a saturated hydrocarbylene group having 1 to 10 carbon atoms. 32 is a single bond, an ester bond, an ether bond or a sulfonamide bond. * indicates a bond to a carbon atom in the main chain.)

11. 2. The chemically amplified positive resist composition according to claim 1, further comprising a quencher.

12. 2. The chemically amplified positive resist composition according to claim 1, further comprising a photoacid generator other than the photoacid generator represented by formula (A).

13. A method for forming a resist pattern, comprising the steps of: forming a resist film on a substrate using the chemically amplified positive resist composition according to any one of claims 1 to 12; exposing the resist film to high-energy rays; and developing the exposed resist film using an alkaline developer to obtain a resist pattern.

14. 14. The method for forming a resist pattern according to claim 13, wherein the high-energy radiation is extreme ultraviolet radiation or an electron beam.

15. 14. The method for forming a resist pattern according to claim 13, 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.

16. 14. The method for forming a resist pattern according to claim 13, wherein the substrate is a transmission or reflection mask blank.

17. A transmission or reflection mask blank coated with the chemically amplified positive resist composition according to any one of claims 1 to 12.

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