Resist material and pattern forming method

Abstract

To provide a resist material which has high sensitivity and improved LWR and CDU regardless of whether it is positive or negative, and a pattern forming method using the same.SOLUTION: The resist material contains a bis-onium salt containing: a divalent anion which has a sulfonic acid anion structure directly bonded to an aromatic group substituted with an iodine atom, and a carboxylic acid anion structure bonded to the aromatic group directly or via a linking group containing one or more atoms; and an onium cation.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resist material and a patterning method.

Background Art

[0002] With the increasing integration and speed of LSIs, the miniaturization of pattern rules has been rapidly progressing. This is because the high-speed communication of 5G and the spread of artificial intelligence (AI) are advancing, and high-performance devices for processing them are required. As the most advanced miniaturization technology, mass production of 5nm node and 3nm node devices by extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm is being carried out. Furthermore, studies using EUV lithography are also underway for next-generation 2nm node devices and sub-next-generation 14Å nodes, and IMEC in Belgium has announced the development of 2Å devices.

[0003] As miniaturization progresses, image blur due to acid diffusion has become a problem. In order to ensure the resolution of fine patterns with a dimensional size of 45nm or less, it has been proposed that not only the improvement of the dissolution contrast proposed conventionally but also the control of acid diffusion is important (Non-Patent Document 1). However, since chemically amplified resist materials increase sensitivity and contrast by acid diffusion, if the post-exposure bake (PEB) temperature is lowered or the time is shortened to suppress acid diffusion to the limit, the sensitivity and contrast are significantly reduced.

[0004] In EUV resist materials, it is necessary to simultaneously achieve high sensitivity, high resolution, and low line width roughness (LWR). Shortening the acid diffusion distance improves LWR and dimensional uniformity (CDU), but reduces sensitivity. For example, lowering the PEB temperature improves LWR and CDU, but reduces sensitivity. Increasing the addition amount of the quencher also improves LWR and CDU, but reduces sensitivity. It is necessary to break the trade-off relationship between sensitivity and LWR.

[0005] Onium salts containing anions having iodine atoms or bromine atoms have been proposed as acid generators in resist materials (Patent Documents 1 to 4). By having iodine atoms with a large EUV absorption or bromine atoms with high ionization efficiency, the efficiency of decomposition of the acid generator during exposure is increased, resulting in higher sensitivity. The amount of photon absorption increases, and the physical contrast can be enhanced.

[0006] EUV light with a wavelength of 13.5 nm has a higher energy and a greater influence of photon number variation compared to ArF excimer laser light with a wavelength of 193 nm (Non-Patent Document 2). It has been pointed out that this causes deterioration of LWR (Non-Patent Document 3). In addition, with the progress of miniaturization, the influence of LWR deterioration due to variations (Resist Stochastics) in the components (polymer, acid generator (PAG), quencher (PDQ)) of the resist material has also been pointed out (Non-Patent Document 4).

[0007] Resist materials containing a polymer in which PAG and PDQ are bonded have been proposed (Patent Document 5). By integrating the polymer, PAG, and PDQ, the variations in their presence are suppressed, and LWR and CDU are improved. Furthermore, resist materials containing an additive in which PAG and PDQ are bonded have also been proposed (Patent Documents 6 and 7).

[0008] The health effects of perfluoroalkyl compounds (PFAS) have been pointed out, and there is a movement to restrict the production and sale of PFAS compounds in European REACH. In the field of semiconductor lithography, many compounds containing PFAS are currently used. For example, materials containing this are used in surfactants, acid generators, etc.

[0009] A comparison of resist materials added with an acid generator that generates anions having fluorine atoms bonded to the polymer main chain and an acid generator that generates anions having no fluorine bonded to the polymer main chain has been reported (Non-Patent Document 5). Here, it is described that the polymer-bound acid generator that generates anions having fluorine atoms has higher resolution. A sulfonic acid with higher acid strength has higher efficiency in the deprotection reaction, and the introduction of fluorine atoms is effective for increasing the acid strength.

[0010] Resist materials that generate anions with increased acidity by introducing nitro groups or chlorine atoms without using fluorine atoms have been reported (Non-Patent Document 6). Resist materials added with an acid generator that generates anions substituted with nitro groups or chlorine atoms may have higher rectangularity compared to resist materials added with an acid generator that generates anions substituted with fluorine atoms. However, as shown in Table 2 of Non-Patent Document 6, they have the drawbacks of low sensitivity and large MEEF, which is due to the low acidity of the anions and the low dissolution contrast caused by the low deprotection reactivity.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Non-Patent Documents

[0012] [Non-Patent Document 1] SPIE Vol. 6520 65203L-1 (2007) [Non-Patent Document 2] SPIE Vol. 3331 535 (1998) [Non-Patent Document 3] SPIE Vol. 7273 727343-1 (2009) [Non-Patent Document 4] SPIE Vol. 9776 97760V-1 (2016) [Non-Patent Document 5] SPIE Vol. 6519 65191F-1 (2007) [Non-Patent Document 6] SPIE Vol. 7639 76390D-1 (2010) [Summary of the Invention] [Problems to be Solved by the Invention]

[0013] There is a demand for the development of a resist material that is more sensitive than conventional resist materials and can improve the LWR of line patterns and the CDU of hole patterns.

[0014] In view of the above circumstances, the present invention aims to provide a resist material that is highly sensitive and has improved LWR and CDU, whether it is a positive type or a negative type, and a pattern formation method using the same. [Means for Solving the Problems]

[0015] As a result of intensive studies to achieve the above object, the present inventors have found that a sulfonic acid anion structure directly bonded to an aromatic group substituted with an iodine atom and a carboxylic acid anion structure bonded to the aromatic group directly or via a linking group containing one or more atoms, and a bis-onium salt containing an onium cation are used as an acid generator and a quencher, so that an acid generator with high absorption is directly excited by radiation exposure, the influence of secondary electron diffusion is eliminated, acid diffusion is controlled by a neighboring quencher, and the influence of image blur due to diffusion can be minimized. Thus, a resist material with high sensitivity, improved LWR and CDU, high contrast, excellent resolution, and a wide process margin can be obtained, and the present invention has been completed.

[0016] That is, the present invention provides the following resist materials and pattern forming methods. 1. A resist material containing a divalent anion having a sulfonic acid anion structure directly bonded to an aromatic group substituted with an iodine atom and a carboxylic acid anion structure bonded to the aromatic group directly or via a linking group containing one or more atoms, and a bis-onium salt containing an onium cation. 2. The resist material of 1, wherein the bis-onium salt is represented by the following formula (1). [Chemical formula] (In the formula, p is an integer from 1 to 5. q is an integer from 0 to 7. X 1 ~X 3 are each independently a single bond, an ether bond, an ester bond, or an amide bond. R 1 ~R 3 are each independently a single bond or a hydrocarbylene group having 1 to 30 carbon atoms, and the hydrocarbylene group may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom. However, the upper limit of the total carbon number of R 1 ~R 3 is 30. R 4is a hydrogen atom, a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms, -N(R 4A )-C(=O)-R 4B , -N(R 4A )-C(=O)-O-R 4B or -N(R 4A )-S(=O) 2 -R 4B , wherein the hydrocarbyl group, hydrocarbyloxy group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, hydrocarbylsulfonyloxy group may contain at least one selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, an amino group, an ester bond, an ether bond, a urethane bond, a urea bond, a carbonate bond, an amide bond, a sulfonic acid ester bond, a carbonyl group, a sulfide group, and a sulfonyl group. R 4A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and the saturated hydrocarbyl group may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. R 4B is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms or an aryl group having 6 to 12 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. Ar is an (p + q + 1)-valent aromatic hydrocarbon group having 6 to 16 carbon atoms. M + is a sulfonium cation or an iodonium cation.) 3. Further, a resist material containing 1 or 2 of a base polymer. 4. The resist material of 3, wherein the base polymer contains a repeating unit represented by the following formula (a1) or (a2). [Chemical formula] (In the formula, R A is independently a hydrogen atom or a methyl group. Y 1 is a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 12 carbon atoms containing at least one selected from an ester bond, an ether bond and a lactone ring, and the phenylene group, naphthylene group and linking group may have at least one selected from a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms and a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are each independently an acid-labile group. R 13 is a saturated hydrocarbyl group having 1 to 4 carbon atoms, a halogen atom, a saturated hydrocarbylcarbonyl group having 2 to 5 carbon atoms, a cyano group or a saturated hydrocarbyloxycarbonyl group having 2 to 5 carbon atoms. R 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain an ether bond or an ester bond. a is an integer from 0 to 4.) 5. The resist material of 4, which is a chemically amplified positive resist material. 6. The resist material of 3, wherein the base polymer does not contain an acid-labile group. 7. The resist material of 6, which is a chemically amplified negative resist material. 8. The resist material of any one of 1 to 7, further containing an organic solvent. 9. The resist material of any one of 1 to 8, further containing a quencher. 10. The resist material of any one of 1 to 9, further containing an acid generator. 11. Further, a resist material containing a surfactant and being any one of 1 to 10. 12. A pattern forming method including a step of forming a resist film on a substrate using a resist material being any one of 1 to 11, a step of exposing the resist film with high energy rays, and a step of developing the exposed resist film using a developer. 13. The pattern forming method according to 12, wherein the high energy rays are ArF excimer laser light having a wavelength of 193 nm, KrF excimer laser light having a wavelength of 248 nm, an electron beam (EB), or EUV having a wavelength of 3 to 15 nm.

Effects of the Invention

[0017] The onium salt of arylsulfonic acid substituted with an iodine atom has a greater absorption of EUV light, a higher acid strength, and suppresses acid diffusion than unsubstituted arylsulfonic acid and even arylsulfonic acid substituted with fluorine. The ratio of the direct excitation reaction due to high absorption increases, suppressing the diffusion of secondary electrons. A bisonium salt having an anion with a structure in which a quencher is further bonded to the arylsulfonic acid substituted with an iodine atom also has a high effect of suppressing acid diffusion and can suppress the image blur due to the diffusion of both secondary electrons and acid to the limit. The bisonium salt is in a form in which an onium salt as an acid generator that generates sulfonic acid and an onium salt as a quencher are bonded and the acid generator and the quencher are always arranged at a constant distance. Therefore, a resist film containing this has improved LWR and CDU due to the improvement of the aforementioned Resist Stochastics. That is, it becomes possible to construct a resist material having high sensitivity and improved LWR and CDU by the bisonium salt.

Modes for Carrying Out the Invention

[0018] [Resist Material] The resist material of the present invention contains a divalent anion having a sulfonic acid anion structure directly bonded to an aromatic group substituted with an iodine atom and a carboxylic acid anion structure bonded directly to the aromatic group or via a linking group containing one or more atoms, and a bis-onium salt containing an onium cation. The bis-onium salt combines the absorption of iodine atoms, high reactivity due to high acidity, and acid diffusion controllability due to the constant presence of a quencher in the vicinity, resulting in small acid diffusion and a uniform diffusion distance. As a result, LWR and CDU can be improved.

[0019] The effect of improving LWR and CDU by the bis-onium salt is effective in both positive pattern formation and negative pattern formation by alkali aqueous solution development, and in negative pattern formation in organic solvent development.

[0020] [Bis-onium salt] As the bis-onium salt, those represented by the following formula (1) are preferable. [Chemical formula]

[0021] In formula (1), p is an integer of 1 to 5. q is an integer of 0 to 7.

[0022] In formula (1), X 1 ~X 3 are each independently a single bond, an ether bond, an ester bond or an amide bond.

[0023] In formula (1), R 1 ~R 3 are each independently a single bond or a hydrocarbylene group having 1 to 30 carbon atoms, and the hydrocarbylene group may contain at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom and a halogen atom. However, the upper limit of the total number of carbon atoms of R 1 ~R 3 is 30.

[0024] R 1~R 3The hydrocarbylene group represented by may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include hydrocarbylene groups having 1 to 24 carbon atoms in which part or all of the hydrogen atoms are substituted with iodine atoms or bromine atoms.Examples of the hydrocarbylene group having 1 to 24 carbon atoms include alkanediyl groups such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, octadecane-1,18-diyl group, nonadecane-1,19-diyl group, eicosane-1,20-diyl group; cyclic saturated hydrocarbylene groups such as cyclopropanediyl group, cyclobutanediyl group, cyclopentanediyl group, methylcyclopentanediyl group, dimethylcyclopentanediyl group, trimethylcyclopentanediyl group, tetramethylcyclopentanediyl group, cyclohexanediyl group, methylcyclohexanediyl group, dimethylcyclohexanediyl group, trimethylcyclohexanediyl group, tetramethylcyclohexanediyl group, norbornanediyl group, adamantanediyl group; alkenediyl groups having 2 to 20 carbon atoms such as ethenediyl group, propenediyl group, butenediyl group; alkynediyl groups having 2 to 20 carbon atoms such as ethynediyl group, propynediyl group, butynediyl group; arylene groups such as phenylene group, methylphenylene group, ethylphenylene group, n-propylphenylene group, isopropylphenylene group, n-butylphenylene group, isobutylphenylene group, sec-butylphenylene group, tert-butylphenylene group, naphthylene group, methylnaphthylene group, ethylnaphthylene group, n-propylnaphthylene group, isopropylnaphthylene group, n-butylnaphthylene group, isobutylnaphthylene group, sec-butylnaphthylene group, tert-butylnaphthylene group, tetrahydronaphthylene group, biphenyldiyl group, methylbiphenyldiyl group, dimethylbiphenyldiyl group; and groups obtained by combining these.Also, some or all of the hydrogen atoms of the hydrocarbylene group may be substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom, and -CH of the hydrocarbylene group. 2 - may be partially substituted with a group containing at least one selected from an oxygen atom, a nitrogen atom, and a sulfur atom, and as a result, it may contain a hydroxy group, an ester bond, an ether bond, an amide bond, a carbamate bond, a urea bond, etc.

[0025] In formula (1), R 4 is a hydrogen atom, a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms, -N(R 4A )-C(=O)-R 4B , -N(R 4A )-C(=O)-O-R 4B or -N(R 4A )-S(=O) 2 -R 4B , and the hydrocarbyl group, hydrocarbyloxy group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, hydrocarbylsulfonyloxy group may contain at least one selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, an amino group, an ester bond, an ether bond, a urethane bond, a urea bond, a carbonate bond, an amide bond, a sulfonic acid ester bond, a carbonyl group, a sulfide group, and a sulfonyl group. R 4A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and the saturated hydrocarbyl group may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. R 4Bis an aliphatic hydrocarbyl group having 1 to 16 carbon atoms or an aryl group having 6 to 12 carbon atoms, and may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms.

[0026] R 4 The hydrocarbyl group represented by and the hydrocarbyl moieties of the hydrocarbyloxy group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy 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 methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, heptadecyl group, octadecyl group, nonadecyl group, and icosyl group; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms such as cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, and adamantyl group; alkenyl groups having 2 to 20 carbon atoms such as vinyl group, propenyl group, butenyl group, and hexenyl group; alkynyl groups having 2 to 20 carbon atoms such as ethynyl group, propynyl group, and butynyl group; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 20 carbon atoms such as cyclohexenyl group and norbornenyl group; aryl groups having 6 to 20 carbon atoms such as phenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, isopropylphenyl group, n-butylphenyl group, isobutylphenyl group, sec-butylphenyl group, tert-butylphenyl group, naphthyl group, methylnaphthyl group, ethylnaphthyl group, n-propylnaphthyl group, isopropylnaphthyl group, n-butylnaphthyl group, isobutylnaphthyl group, sec-butylnaphthyl group, and tert-butylnaphthyl group; aralkyl groups having 7 to 20 carbon atoms such as benzyl group and phenethyl group; and groups obtained by combining these.

[0027] In formula (1), Ar is a (p + q + 1)-valent aromatic hydrocarbon group having 6 to 16 carbon atoms. Specific examples of the aromatic hydrocarbon group include groups obtained by eliminating (p + q + 1) hydrogen atoms from aromatic hydrocarbons such as benzene, naphthalene, anthracene, and pyrene.

[0028] Specific examples of the anion of the bis-onium salt include, but are not limited to, those shown below.

Chemical formula

[0029]

Chemical formula

[0030]

Chemical formula

[0031]

Chemical formula

[0032]

Chemical formula

[0033]

Chemical formula

[0034]

Chemical formula

[0035]

Chemical formula

[0036]

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[0053]

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[0054]

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[0055]

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[0056] In formula (1), M + is a sulfonium cation or an iodonium cation. Two Ms +One may be a sulfonium cation and the other may be an iodonium cation, or both may be sulfonium cations, or both may be iodonium cations. The two M + If both are sulfonium cations, they may be the same as each other or different from each other. Also, the two M + If both are iodonium cations, they may be the same as each other or different from each other.

[0057] As the sulfonium cation, those represented by the following formula (2) are preferred, and as the iodonium cation, those represented by the following formula (3) are preferred.

Chemical formula

[0058] In formulas (2) and (3), R 5 ~R 9 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom.

[0059] R 5 ~R 9 Specific examples of the halogen atom represented by are a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.

[0060] R 5 ~R 9The hydrocarbyl group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, etc.; cyclic saturated hydrocarbyl groups having 3 to 20 carbon atoms such as cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, adamantyl group, etc.; alkenyl groups having 2 to 20 carbon atoms such as vinyl group, propenyl group, butenyl group, hexenyl group, etc.; alkynyl groups having 2 to 20 carbon atoms such as ethynyl group, propynyl group, butynyl group, etc.; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 20 carbon atoms such as cyclohexenyl group, norbornenyl group, etc.; aryl groups having 6 to 20 carbon atoms such as phenyl group, methylphenyl group, ethylphenyl group, n-propylphenyl group, isopropylphenyl group, n-butylphenyl group, isobutylphenyl group, sec-butylphenyl group, tert-butylphenyl group, naphthyl group, methylnaphthyl group, ethylnaphthyl group, n-propylnaphthyl group, isopropylnaphthyl group, n-butylnaphthyl group, isobutylnaphthyl group, sec-butylnaphthyl group, tert-butylnaphthyl group, etc.; aralkyl groups having 7 to 20 carbon atoms such as benzyl group, phenethyl group, etc.; and groups obtained by combining these.

[0061] Further, 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, a halogen atom, etc., and the -CH of the hydrocarbyl group 2- may be partially substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom, and as a result, it may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a mercapto group, a pentafluorosulfanyl group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc.

[0062] Also, R 5 and R 6 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. At this time, the ring is preferably one having the following structures. [Chemical formula] (In the formula, the dashed line represents a bond.)

[0063] M + Specific examples of the sulfonium cation represented by include, but are not limited to, those shown below. [Chemical formula]

[0064] [Chemical formula]

[0065] [Chemical formula]

[0066] [Chemical formula]

[0067] [Chemical formula]

[0068] [Chemistry]

[0069] [Chemistry]

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[0097] [Chemical]

[0098] M + Specific examples of the iodonium cation represented by M include, but are not limited to, those shown below. [Chemical]

[0099] [Chemical formula]

[0100] As a method for synthesizing the bis-onium salt, for example, a method of performing salt exchange between a sulfonium salt or iodonium salt containing a halide anion and an ammonium salt containing a divalent anion having a sulfonic acid anion structure directly bonded to an aromatic group having an iodine atom or a bromine atom and a carboxylic acid anion structure bonded to the aromatic group having the iodine atom or the bromine atom via a linking group having 1 or more carbon atoms can be mentioned.

[0101] In the resist material of the present invention, the content of the bis-onium salt is preferably 0.01 to 1000 parts by mass, more preferably 0.05 to 500 parts by mass, from the viewpoints of sensitivity and acid diffusion suppression effect, with respect to 100 parts by mass of the base polymer described later.

[0102] [Base polymer] The base polymer contained in the resist material of the present invention contains a repeating unit containing an acid-labile group in the case of a positive resist material. As the repeating unit containing an acid-labile group, a repeating unit represented by the following formula (a1) (hereinafter, also referred to as repeating unit a1) or a repeating unit represented by formula (a2) (hereinafter, also referred to as repeating unit a2) is preferable. [Chemical formula]

[0103] In formulas (a1) and (a2), R A is each independently a hydrogen atom or a methyl group. Y 1 is a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 12 carbon atoms containing at least one selected from an ester bond, an ether bond and a lactone ring, and the phenylene group, naphthylene group and linking group may have at least one selected from a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms and a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms. Y 2is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are each independently an acid-labile group. R 13 is a saturated hydrocarbyl group having 1 to 4 carbon atoms, a halogen atom, a saturated hydrocarbylcarbonyl group having 2 to 5 carbon atoms, a cyano group or a saturated hydrocarbyloxycarbonyl group having 2 to 5 carbon atoms. R 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain an ether bond or an ester bond. a is an integer of 0 to 4.

[0104] Specific examples of the monomer that gives the repeating unit a1 include, but are not limited to, those shown below. In the following formulas, R A and R 11 are the same as described above.

Chemical formula

[0105]

Chemical formula

[0106]

Chemical formula

[0107] Specific examples of the monomer that gives the repeating unit a2 include, but are not limited to, those shown below. In the following formulas, R A and R 12 are the same as described above.

Chemical formula

[0108] In R 11 and R 12Examples of the acid-labile group represented by [ ] include those described in JP-A No. 2013-80033 and JP-A No. 2013-83821.

[0109] Typically, specific examples of the acid-labile group include those represented by any of the following formulas (AL-1) to (AL-3).

Chemical formula

[0110] In formulas (AL-1) and (AL-2), R L1 and R L2 are each independently a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 40 carbon atoms is preferable, and a saturated hydrocarbyl group having 1 to 20 carbon atoms is more preferable.

[0111] In formula (AL-1), b is an integer of 0 to 10, and an integer of 1 to 5 is preferable.

[0112] In formula (AL-2), R L3 and R L4 are each independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 20 carbon atoms is preferable. Further, any two of R L2 , R L3 and R L4 may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded or a carbon atom and an oxygen atom. As the ring, a ring having 4 to 16 carbon atoms is preferable, and an alicyclic ring is particularly preferable.

[0113] In formula (AL-3), RL5 , R L6 and R L7 are each independently a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 20 carbon atoms is preferred. Also, R L5 , R L6 and R L7 any two of may be bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atoms to which they are bonded. As the ring, a ring having 4 to 16 carbon atoms is preferred, and an alicyclic ring is particularly preferred.

[0114] The base polymer may contain a repeating unit b containing a phenolic hydroxy group as an adhesion group. Specific examples of the monomer that gives the repeating unit b include, but are not limited to, those shown below. In the following formulas, R A is the same as described above.

Chemical formula

[0115] The base polymer may contain a repeating unit c containing a hydroxy group other than a phenolic hydroxy group, a lactone ring, a sultone ring, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonyl group, a sulfonyl group, a cyano group, or a carboxy group as another adhesion group. Specific examples of the monomer that gives the repeating unit c include, but are not limited to, those shown below. In the following formulas, R A is the same as described above.

Chemical formula

[0116]

Chemical formula

[0117] [Chemistry]

[0118] [Chemistry]

[0119] [Chemistry]

[0120] [Chemistry]

[0121] [Chemistry]

[0122] [Chemistry]

[0123] The base polymer may contain a repeating unit d derived from indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene, or derivatives thereof. Specific examples of the monomer that gives the repeating unit d include, but are not limited to, those shown below. [Chemistry]

[0124] The base polymer may contain a repeating unit e derived from styrene, vinylnaphthalene, vinylanthracene, vinylpyrene, methylene indane, vinylpyridine, or vinylcarbazole.

[0125] The base polymer may contain a repeating unit f derived from an onium salt containing a polymerizable unsaturated bond. Japanese Patent Application Laid-Open No. 2005-84365 has proposed sulfonium salts and iodonium salts containing polymerizable olefins that generate specific sulfonic acids. Japanese Patent Application Laid-Open No. 2006-178317 has proposed sulfonium salts in which sulfonic acid is directly bonded to the main chain.

[0126] Specific examples of the preferred repeating unit f include a repeating unit represented by the following formula (f1) (hereinafter also referred to as repeating unit f1), a repeating unit represented by the following formula (f2) (hereinafter also referred to as repeating unit f2), and a repeating unit represented by the following formula (f3) (hereinafter also referred to as repeating unit f3). The repeating units f1 to f3 may be used alone or in combination of two or more.

Chemical formula

[0127] In formulas (f1) to (f3), R A is independently a hydrogen atom or a methyl group. Z 1 is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, or -O-Z 11 -, -C(=O)-O-Z 11 - or -C(=O)-NH-Z 11 -. Z 11 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, or a hydroxy group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -O-C(=O)-. Z 31is an aliphatic hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by combining these, and may contain a carbonyl group, an ester bond, an ether bond, an iodine atom or a bromine atom. Z 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethanediyl group or a carbonyl group. Z 5 is a single bond, a methylene group, an ethylene group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, -O-Z 51 -, -C(=O)-O-Z 51 - or -C(=O)-NH-Z 51 -. Z 51 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, a hydroxy group or a halogen atom.

[0128] In formulas (f1) to (f3), R 21 ~R 28 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include those exemplified as the hydrocarbyl groups represented by R 5 ~R 9 in the descriptions of formulas (2) and (3). Further, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and -CH of the hydrocarbyl group 2- may be partially substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. Also, R 23 and R 24 or R 26 and R 27 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. At this time, specific examples of the ring include those exemplified as the rings that can be formed by R 5 and R 6 being bonded to each other and together with the sulfur atom to which they are bonded in the description of formula (2).

[0129] In formula (f1), 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.

[0130] Specific examples of the non-nucleophilic counter ion further include sulfonate ions in which the α-position is substituted with a fluorine atom and represented by the following formula (f1-1), sulfonate ions in which the α-position is substituted with a fluorine atom and the β-position is substituted with a trifluoromethyl group and represented by the following formula (f1-2), and the like.

Chemical formula

[0131] In formula (f1-1), R 31 is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may contain at least one selected from an ether bond, an ester bond, a carbonyl group, a lactone ring, and a fluorine atom.

[0132] In formula (f1-2), R 32 is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbylcarbonyl group having 2 to 30 carbon atoms, and may contain at least one selected from an ether bond, an ester bond, a carbonyl group, and a lactone ring.

[0133] R 31 or R 32The hydrocarbyl groups and the hydrocarbyl moieties of hydrocarbylcarbonyl groups represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, 2-ethylhexyl group, nonyl group, undecyl group, tridecyl group, pentadecyl group, heptadecyl group, icosyl group; cyclic saturated hydrocarbyl groups such as cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, 1-adamantylmethyl group, norbornyl group, norbornylmethyl group, tricyclodecanyl group, tetracyclododecanyl group, tetracyclododecanylmethyl group, dicyclohexylmethyl group; alkenyl groups such as allyl group; cyclic unsaturated hydrocarbyl groups such as 3-cyclohexenyl group; aryl groups such as phenyl group, 1-naphthyl group, 2-naphthyl group; aralkyl groups such as benzyl group, diphenylmethyl group, etc.

[0134] Also, some or all of the hydrogen atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atom, sulfur atom, nitrogen atom, halogen atom, etc., and some of the carbon atoms of these groups may be substituted with heteroatom-containing groups such as oxygen atom, sulfur atom, nitrogen atom, etc. As a result, it may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate group, a lactone ring, a sultone ring, a carboxylic acid anhydride, a haloalkyl group, etc. Specific examples of the hydrocarbyl group containing a heteroatom include tetrahydrofuryl group, methoxymethyl group, ethoxymethyl group, methylthiomethyl group, acetamidomethyl group, trifluoroethyl group, (2-methoxyethoxy)methyl group, acetoxymethyl group, 2-carboxy-1-cyclohexyl group, 2-oxopropyl group, 4-oxo-1-adamantyl group, 3-oxocyclohexyl group, etc.

[0135] Specific examples of the cation of the monomer that gives the repeating unit f1 include, but are not limited to, those shown below. In the following formula, RA is the same as the above.

Chem.

[0136] Specific examples of the cations of the monomers that give the repeating unit f2 or f3 include those exemplified as the sulfonium cations represented by M in the description of Formula (1). + Examples thereof include those similar to those exemplified as the sulfonium cations represented by M in the description of Formula (1).

[0137] Specific examples of the monomers that give the repeating unit f2 include, but are not limited to, the following. In the following formulas, R A is the same as the above.

Chem.

[0138]

Chem.

[0139]

Chem.

[0140]

Chem.

[0141]

Chem.

[0142]

Chem.

[0143]

Chem.

[0144]

Chem.

[0145]

Chem.

[0146]

Chem.

[0147]

Chem.

[0148]

Chem.

[0149]

Chem.

[0150]

Chem.

[0151] Specific examples of the monomer that gives the repeating unit f3 include, but are not limited to, those shown below. In the following formula, R A is the same as described above.

Chem.

[0152] The repeating units f1 to f3 function as an acid generator. By bonding the acid generator to the polymer main chain, acid diffusion can be reduced, and a decrease in resolution due to blurring of acid diffusion can be prevented. In addition, the LWR and CDU are improved by the uniform dispersion of the acid generator.

[0153] The base polymer for the positive resist material essentially contains a repeating unit a1 or a2 containing an acid-labile group. In this case, the content ratios of the repeating units a1, a2, b, c, d, e, and f are preferably 0 ≦ a1 < 1.0, 0 ≦ a2 < 1.0, 0 < a1 + a2 < 1.0, 0 ≦ b ≦ 0.9, 0 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.8, 0 ≦ e ≦ 0.8, and 0 ≦ f ≦ 0.5, more preferably 0 ≦ a1 ≦ 0.9, 0 ≦ a2 ≦ 0.9, 0.1 ≦ a1 + a2 ≦ 0.9, 0 ≦ b ≦ 0.8, 0 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.7, 0 ≦ e ≦ 0.7, and 0 ≦ f ≦ 0.4, and still more preferably 0 ≦ a1 ≦ 0.8, 0 ≦ a2 ≦ 0.8, 0.1 ≦ a1 + a2 ≦ 0.8, 0 ≦ b ≦ 0.75, 0 ≦ c ≦ 0.75, 0 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.6, and 0 ≦ f ≦ 0.3. When the repeating unit f is at least one selected from the repeating units f1 to f3, f = f1 + f2 + f3. Also, a1 + a2 + b + c + d + e + f = 1.0.

[0154] On the other hand, the base polymer for the negative resist material does not necessarily require an acid-labile group. Examples of such a base polymer include those containing the repeating unit b and, if necessary, further containing the repeating units c, d, e, and / or f. The content ratios of these repeating units are preferably 0 < b ≦ 1.0, 0 ≦ c ≦ 0.9, 0 ≦ d ≦ 0.8, 0 ≦ e ≦ 0.8, and 0 ≦ f ≦ 0.5, more preferably 0.2 ≦ b ≦ 1.0, 0 ≦ c ≦ 0.8, 0 ≦ d ≦ 0.7, 0 ≦ e ≦ 0.7, and 0 ≦ f ≦ 0.4, and still more preferably 0.3 ≦ b ≦ 1.0, 0 ≦ c ≦ 0.75, 0 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.6, and 0 ≦ f ≦ 0.3. When the repeating unit f is at least one selected from the repeating units f1 to f3, f = f1 + f2 + f3. Also, b + c + d + e + f = 1.0.

[0155] To synthesize the base polymer, for example, a monomer that provides the above-described repeating unit may be heated in an organic solvent with a radical polymerization initiator added thereto to perform polymerization.

[0156] Specific examples of the organic solvents used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, dioxane, and the like. Specific examples of the polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide, and the like. The temperature during polymerization is preferably 50 to 80 °C. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

[0157] When copolymerizing a monomer containing a hydroxy group, the hydroxy group may be substituted with an acetal group that is easily deprotected by an acid such as an ethoxyethoxy group during polymerization, and then deprotected with a weak acid and water after polymerization, or it may be substituted with an acetyl group, a formyl group, a pivaloyl group, etc., and then subjected to alkaline hydrolysis after polymerization.

[0158] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, acetoxystyrene or acetoxyvinylnaphthalene may be used instead of hydroxystyrene or hydroxyvinylnaphthalene, and the acetoxy group may be deprotected by the above-mentioned alkaline hydrolysis after polymerization to obtain hydroxystyrene or hydroxyvinylnaphthalene.

[0159] As the base during alkaline hydrolysis, aqueous ammonia, triethylamine, etc. can be used. Also, the reaction temperature is preferably -20 to 100 °C, more preferably 0 to 60 °C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0160] The base polymer preferably has a polystyrene-equivalent weight average molecular weight (Mw) of 1000 to 500000, more preferably 2000 to 30000, as determined by gel permeation chromatography (GPC) using THF as the solvent. If Mw is within the above range, the heat resistance of the resist film and its solubility in an alkaline developer are good.

[0161] Furthermore, when the base polymer has a broad molecular weight distribution (Mw / Mn), there are low molecular weight and high molecular weight polymers present. Therefore, after exposure, foreign matter may be seen on the pattern or the shape of the pattern may deteriorate. As the pattern rules become finer, the influence of Mw and Mw / Mn tends to increase. Thus, in order to obtain a resist material suitably used for fine pattern dimensions, the Mw / Mn of the base polymer is preferably narrowly dispersed in the range of 1.0 to 2.0, particularly 1.0 to 1.5.

[0162] The base polymer may contain two or more polymers having different composition ratios, Mw, and Mw / Mn.

[0163] [Organic solvent] The resist material of the present invention may contain an organic solvent. The organic solvent is not particularly limited as long as it can dissolve each of the foregoing components and each of the components described hereinafter. Specific examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone described in paragraphs

[0144] to

[0145] of JP-A-2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as γ-butyrolactone, and the like.

[0164] In the resist material of the present invention, the content of the organic solvent is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass, based on 100 parts by mass of the base polymer. The organic solvent may be used alone or in combination of two or more.

[0165] [Quencher] The resist material of the present invention may contain a quencher. The quencher means a compound that can prevent the diffusion to the unexposed part by trapping the acid generated from the acid generator in the resist material.

[0166] Examples of the quencher include conventional basic compounds. Specific examples of the conventional basic compounds include primary, secondary, and tertiary aliphatic amines, hybrid amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxy group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxy group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, carbamates, and the like. In particular, the primary, secondary, and tertiary amine compounds described in paragraphs

[0146] to

[0164] of JP-A-2008-111103, especially amine compounds having a hydroxy group, an ether bond, an ester bond, a lactone ring, a cyano group, a sulfonic acid ester bond, or compounds having a carbamate bond described in Japanese Patent No. 3790649 are preferable. By adding such a basic compound, for example, the diffusion rate of the acid in the resist film can be further suppressed or the shape can be corrected.

[0167] In addition, examples of the quencher include onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids, carboxylic acids, or fluorinated alkoxides in which the α-position is not fluorinated, as described in JP-A-2008-158339. Sulfonic acids, imidic acids, or methidic acids in which the α-position is fluorinated are necessary for deprotecting the acid-labile group of the carboxylic acid ester, but sulfonic acids, carboxylic acids, or fluorinated alcohols in which the α-position is not fluorinated are released by salt exchange with the onium salt. Sulfonic acids, carboxylic acids, and fluorinated alcohols in which the α-position is not fluorinated do not cause a deprotection reaction and thus function as a quencher.

[0168] Specific examples of such a quencher include, for example, a compound represented by the following formula (4) (onium salt of a sulfonic acid in which the α-position is not fluorinated), a compound represented by the following formula (5) (onium salt of a carboxylic acid), and a compound represented by the following formula (6) (onium salt of an alkoxide).

Chemical formula

[0169] In formula (4), R 101 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a hydrogen atom or a hetero atom, provided that a hydrogen atom bonded to the carbon atom at the α-position of the sulfo group is excluded when it is substituted with a fluorine atom or a fluoroalkyl group.

[0170] R 101The hydrocarbyl group having 1 to 40 carbon atoms represented by may be saturated or unsaturated, and may be linear, branched or cyclic. Specific examples thereof include alkyl groups having 1 to 40 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, tert-pentyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, etc.; cyclic saturated hydrocarbyl groups having 3 to 40 carbon atoms such as cyclopentyl group, cyclohexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylbutyl group, norbornyl group, tricyclo[5.2.1.0 2,6 decyl group, adamantyl group, adamantylmethyl group, etc.; alkenyl groups having 2 to 40 carbon atoms such as vinyl group, allyl group, propenyl group, butenyl group, hexenyl group, etc.; cyclic unsaturated aliphatic hydrocarbyl groups having 3 to 40 carbon atoms such as cyclohexenyl group, etc.; aryl groups having 6 to 40 carbon atoms such as phenyl group, naphthyl group, alkylphenyl group (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-n-butylphenyl group, etc.), di- or trialkylphenyl group (2,4-dimethylphenyl group, 2,4,6-triisopropylphenyl group, etc.), alkylnaphthyl group (methylnaphthyl group, ethylnaphthyl group, etc.), dialkylnaphthyl group (dimethylnaphthyl group, diethylnaphthyl group, etc.), etc.; aralkyl groups having 7 to 40 carbon atoms such as benzyl group, 1-phenylethyl group, 2-phenylethyl group, etc.

[0171] In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, a halogen atom, etc., and the -CH of the hydrocarbyl group 2Part of "-" may be substituted with a group containing a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. As a result, it may contain a hydroxy group, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-O-C(=O)-), a haloalkyl group, etc. Specific examples of the hydrocarbyl group containing a heteroatom include heteroaryl groups such as a thienyl group; alkoxyphenyl groups such as a 4-hydroxyphenyl group, a 4-methoxyphenyl group, a 3-methoxyphenyl group, a 2-methoxyphenyl group, a 4-ethoxyphenyl group, a 4-tert-butoxyphenyl group, a 3-tert-butoxyphenyl group, etc.; alkoxynaphthyl groups such as a methoxynaphthyl group, an ethoxynaphthyl group, an n-propoxynaphthyl group, an n-butoxynaphthyl group, etc.; dialkoxynaphthyl groups such as a dimethoxynaphthyl group, a diethoxynaphthyl group, etc.; aryloxoalkyl groups such as a 2-aryl-2-oxoethyl group such as a 2-phenyl-2-oxoethyl group, a 2-(1-naphthyl)-2-oxoethyl group, a 2-(2-naphthyl)-2-oxoethyl group, etc.

[0172] In formula (5), R 102 is a hydrocarbyl group having 1 to 40 carbon atoms which may contain a heteroatom. Specific examples of the hydrocarbyl group represented by R 102 include the same ones as those exemplified as the hydrocarbyl group represented by R 101 In addition, as other specific examples, fluorinated alkyl groups such as a trifluoromethyl group, a trifluoroethyl group, a 2,2,2-trifluoro-1-methyl-1-hydroxyethyl group, a 2,2,2-trifluoro-1-(trifluoromethyl)-1-hydroxyethyl group, etc.; fluorinated aryl groups such as a pentafluorophenyl group, a 4-trifluoromethylphenyl group, etc. are also included.

[0173] In formula (6), R 103 is a saturated hydrocarbyl group having 1 to 8 carbon atoms having at least 3 fluorine atoms or an aryl group having 6 to 10 carbon atoms having at least 3 fluorine atoms, and may contain a nitro group.

[0174] In formulas (4), (5) and (6), Mq + is an onium cation. As the onium cation, a sulfonium cation, an iodonium cation or an ammonium cation is preferable, and a sulfonium cation is more preferable. As specific examples of the sulfonium cation, in the description of formula (1), M + is the same as those exemplified as the sulfonium cation represented by

[0175] As the quencher, a sulfonium salt of a benzenecarboxylic acid containing an iodinated benzene ring represented by the following formula (7) can also be preferably used. [Chemical formula]

[0176] In formula (7), x is an integer of 1 to 5. y is an integer of 0 to 3. z is an integer of 1 to 3.

[0177] In formula (7), R 111 is a hydroxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms or a saturated hydrocarbylsulfonyloxy group having 1 to 4 carbon atoms, in which part or all of hydrogen atoms may be substituted with halogen atoms, or -N(R 111A )-C(=O)-R 111B or -N(R 111A )-C(=O)-O-R 111B . R 111A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 111B is a saturated hydrocarbyl group having 1 to 6 carbon atoms or an unsaturated aliphatic hydrocarbyl group having 2 to 8 carbon atoms. When y and / or z is 2 or more, each R 111 may be the same as or different from each other.

[0178] In formula (7), L 1is a single bond or a (z + 1)-valent linking group having 1 to 20 carbon atoms, and may contain at least one selected from an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen atom, a hydroxy group, and a carboxy group. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbylcarbonyloxy group, and saturated hydrocarbylsulfonyloxy group may be linear, branched, or cyclic.

[0179] In formula (7), R 112 , R 113 and R 114 are each independently a halogen atom or a hydrocarbyl group having 1 to 20 carbon atoms which may contain a hetero atom. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the same ones as those exemplified as the hydrocarbyl groups represented by R 5 to R 9 in the descriptions of formulas (2) and (3).

[0180] Specific examples of the compound represented by formula (7) include those described in JP-A-2017-219836 and JP-A-2021-91666.

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

[0182] Furthermore, betaine-type sulfonium salts described in Japanese Patent No. 6848776 and JP-A-2020-37544, methide acids containing no fluorine atoms described in JP-A-2020-55797, sulfonium salts of sulfonamides described in Japanese Patent No. 5807552, sulfonium salts of sulfonamides containing iodine atoms described in JP-A-2019-211751, phenols, halogen, or an acid generator that generates carbonic acid can also be used as a quencher.

[0183] When the resist material of the present invention contains the quencher, its content is preferably 0 to 5 parts by mass, more preferably 0 to 4 parts by mass, per 100 parts by mass of the base polymer. The quencher may be used alone or in combination of two or more.

[0184] [Other Components] In addition to the components described above, an acid generator other than the salt represented by formula (1) (hereinafter referred to as other acid generator), a surfactant, a dissolution inhibitor, a crosslinking agent, a water repellency improver, acetylene alcohols, etc. may be included.

[0185] Examples of the other acid generator include compounds (photoacid generators) that generate an acid upon exposure to actinic rays or radiation. As the components of the photoacid generator, any compound that generates an acid upon irradiation with high-energy rays may be used, but acid generators that generate sulfonic acid, imidic acid, or methide acid are preferred. Specific examples of suitable photoacid generators include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate type acid generators, and the like. Specific examples of the acid generator include those described in paragraphs

[0122] to

[0142] of JP-A-2008-111103, JP-A-2018-5224, and JP-A-2018-25789. When the resist material of the present invention contains the other acid generator, its content is preferably 0 to 200 parts by mass, more preferably 0.1 to 100 parts by mass, per 100 parts by mass of the base polymer.

[0186] Specific examples of the surfactant include those described in paragraphs

[0165] to

[0166] of JP-A-2008-111103. By adding the surfactant, the coatability of the resist material can be further improved or controlled. When the resist material of the present invention contains a surfactant, its content is preferably 0.0001 to 10 parts by mass with respect to 100 parts by mass of the base polymer. The surfactant may be used alone or in combination of two or more.

[0187] When the resist material of the present invention is a positive type, by blending a dissolution inhibitor, the difference in dissolution rate between the exposed portion and the unexposed portion can be further increased, and the resolution can be further improved. Specific examples of the dissolution inhibitor include a compound having a molecular weight preferably of 100 to 1000, more preferably 150 to 800, and containing two or more phenolic hydroxy groups in the molecule, and the hydrogen atoms of the phenolic hydroxy groups are substituted as a whole by acid-labile groups at a ratio of 0 to 100 mol%, or a compound having a carboxy group in the molecule, and the hydrogen atoms of the carboxy group are substituted as a whole by acid-labile groups at an average ratio of 50 to 100 mol%. Specifically, bisphenol A, trisphenol, phenolphthalein, cresol novolak, naphthalene carboxylic acid, adamantane carboxylic acid, compounds in which the hydrogen atoms of the hydroxy groups and carboxy groups of cholic acid are substituted with acid-labile groups, etc. are included. For example, they are described in paragraphs

[0155] to

[0178] of JP-A-2008-122932.

[0188] When the resist material of the present invention is a positive type and contains the dissolution inhibitor, its content is preferably 0 to 50 parts by mass, more preferably 5 to 40 parts by mass with respect to 100 parts by mass of the base polymer. The dissolution inhibitor may be used alone or in combination of two or more.

[0189] On the one hand, when the resist material of the present invention is a negative type, a negative pattern can be obtained by adding a crosslinking agent to reduce the dissolution rate of the exposed area. Specific examples of the crosslinking agent include epoxy compounds, melamine compounds, guanamine compounds, glycoluril compounds or urea compounds substituted with at least one group selected from a methylol group, an alkoxymethyl group and an acyloxymethyl group, isocyanate compounds, azide compounds, compounds containing a double bond such as an alkenyloxy group, and the like. These may be used as additives, or may be introduced as pendant groups on the polymer side chain. In addition, compounds containing a hydroxy group can also be used as crosslinking agents.

[0190] Specific examples of the epoxy compound include tris(2,3-epoxypropyl) isocyanurate, trimethylolmethane triglycidyl ether, trimethylolpropane triglycidyl ether, triethylolethane triglycidyl ether, and the like.

[0191] Specific examples of the melamine compound include hexamethylol melamine, hexamethoxymethyl melamine, a compound or a mixture thereof in which 1 to 6 methylol groups of hexamethylol melamine are methoxymethylated, hexamethoxyethyl melamine, hexaacyloxymethyl melamine, a compound or a mixture thereof in which 1 to 6 methylol groups of hexamethylol melamine are acyloxymethylated, and the like.

[0192] Specific examples of the guanamine compound include tetramethylol guanamine, tetramethoxymethyl guanamine, a compound or a mixture thereof in which 1 to 4 methylol groups of tetramethylol guanamine are methoxymethylated, tetramethoxyethyl guanamine, tetraacyloxy guanamine, a compound or a mixture thereof in which 1 to 4 methylol groups of tetramethylol guanamine are acyloxymethylated, and the like.

[0193] Specific examples of the glycoluril compound include tetramethylol glycoluril, tetramethoxy glycoluril, tetramethoxymethyl glycoluril, a compound or mixture thereof in which 1 to 4 of the methylol groups of tetramethylol glycoluril are methoxymethylated, a compound or mixture thereof in which 1 to 4 of the methylol groups of tetramethylol glycoluril are acyloxymethylated, and the like. Specific examples of the urea compound include tetramethylol urea, tetramethoxymethyl urea, a compound or mixture thereof in which 1 to 4 of the methylol groups of tetramethylol urea are methoxymethylated, tetramethoxyethyl urea, and the like.

[0194] Specific examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, and the like.

[0195] Specific examples of the azide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, 4,4'-oxybisazide, and the like.

[0196] Specific examples of the compound containing an alkenyloxy group include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane trivinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, trimethylolpropane trivinyl ether, and the like.

[0197] When the resist material of the present invention is a negative type and contains the crosslinking agent, its content is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass, based on 100 parts by mass of the base polymer. The crosslinking agent may be used alone or in combination of two or more kinds.

[0198] The water repellency improver improves the water repellency of the resist film surface and can be used in immersion lithography without using a top coat. As the water repellency improver, a polymer containing an alkyl fluoride group, a polymer containing a 1,1,1,3,3,3-hexafluoro-2-propanol residue having a specific structure, etc. are preferable, and those exemplified in JP-A-2007-297590, JP-A-2008-111103, etc. are preferable. The water repellency improver needs to be dissolved in an alkaline developer or an organic solvent developer. The water repellency improver having the above-mentioned specific 1,1,1,3,3,3-hexafluoro-2-propanol residue has good solubility in the developer. As the water repellency improver, a polymer containing a repeating unit containing an amino group or an amine salt has a high effect of preventing the evaporation of the acid in PEB and preventing the opening failure of the hole pattern after development. When the resist material of the present invention contains the water repellency improver, its content is preferably 0 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, based on 100 parts by mass of the base polymer. The water repellency improver may be used alone or in combination of two or more kinds and may be used in combination.

[0199] Specific examples of the acetylene alcohols include those described in paragraphs

[0179] to

[0182] of JP-A-2008-122932. When the resist material of the present invention contains the acetylene alcohols, its content is preferably 0 to 5 parts by mass, based on 100 parts by mass of the base polymer. The acetylene alcohols may be used alone or in combination of two or more kinds.

[0200] [Pattern formation method] When the resist material of the present invention is used for various integrated circuit manufacturing, known lithography techniques can be applied. For example, as a pattern formation method, there is a method including a step of forming a resist film on a substrate using the above-described resist material, a step of exposing the resist film with high-energy rays, and a step of developing the exposed resist film using a developer.

[0201] First, the resist material of the present invention is applied onto a substrate for integrated circuit manufacturing (Si, SiO 2 , SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflection film, etc.) or a substrate for mask circuit manufacturing (Cr, CrO, CrON, MoSi 2 , SiO 2 , etc.) by an appropriate coating method such as spin coating, roll coating, flow coating, dip coating, spray coating, doctor coating, etc. so that the coating film thickness becomes 0.01 to 2 μm. This is prebaked on a hot plate, preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 80 to 120°C for 30 seconds to 20 minutes to form a resist film.

[0202] Next, the resist film is exposed using high-energy rays. Specific examples of the high-energy rays include ultraviolet rays, far ultraviolet rays, EB, EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, γ-rays, synchrotron radiation, etc. When using ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer laser light, γ-rays, synchrotron radiation, etc. as the high-energy rays, the exposure amount is preferably about 1 to 200 mJ / cm 2 , more preferably about 10 to 100 mJ / cm 2 , and irradiation is performed so as to be such an amount. When using EB as the high-energy ray, the exposure amount is preferably about 0.1 to 300 μC / cm 2 , more preferably about 0.5 to 200 μC / cm 2It is drawn directly to that extent or using a mask for forming a target pattern. The resist material of the present invention is particularly suitable for fine patterning by KrF excimer laser light, ArF excimer laser light, EB, EUV, X-rays, soft X-rays, γ-rays, synchrotron radiation among high-energy rays, and is particularly suitable for fine patterning by EB or EUV.

[0203] After exposure, PEB may or may not be performed on a hot plate or in an oven, preferably at 30 to 150 °C for 10 seconds to 30 minutes, more preferably at 50 to 120 °C for 30 seconds to 20 minutes.

[0204] After exposure or after PEB, a developer of an alkaline aqueous solution such as 0.1 to 10 mass%, preferably 2 to 5 mass% of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc. is used, and the exposed resist film is developed by an ordinary method such as a dip method, a puddle method, or a spray method for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, to form a target pattern. In the case of a positive resist material, the irradiated portion is dissolved in the developer, and the unexposed portion is not dissolved, and a target positive pattern is formed on the substrate. In the case of a negative resist material, it is the opposite of the case of the positive resist material, and the irradiated portion is insolubilized in the developer, and the unexposed portion is dissolved.

[0205] Using a positive resist material containing a base polymer containing an acid-labile group, a negative pattern can also be obtained by organic solvent development. Specific examples of the developer used at this time include 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, methyl pentenoate, methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents may be used alone or in combination of two or more.

[0206] At the end of development, rinsing is performed. As the rinse liquid, a solvent that is miscible with the developer and does not dissolve the resist film is preferred. As such a solvent, alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes, and aromatic solvents having 6 to 12 carbon atoms are preferably used.

[0207] Specific examples of the alcohol having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol and the like.

[0208] Specific examples of the ether compound having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, di-n-hexyl ether and the like.

[0209] Specific examples of the alkane having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane and the like. Specific examples of the alkene having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene and the like. Specific examples of the alkyne having 6 to 12 carbon atoms include hexyne, heptyne, octyne and the like.

[0210] Specific examples of the aromatic solvent include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, mesitylene, and the like.

[0211] By performing rinsing, it is possible to reduce the occurrence of resist pattern collapse and defects. Also, rinsing is not necessarily essential, and the amount of solvent used can be reduced by not performing rinsing.

[0212] The developed hole pattern or trench pattern can also be shrunk by thermal flow, RELACS technology, or DSA technology. A shrink agent is applied onto the hole pattern, and crosslinking of the shrink agent occurs on the surface of the resist film due to diffusion of the acid catalyst from the resist film during baking, and the shrink agent adheres to the sidewalls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds, to remove the excess shrink agent and shrink the hole pattern.

Examples

[0213] Hereinafter, the present invention will be specifically described by showing synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples.

[0214] The structures of the bis-onium salt PAG-PDQ-1 to PAG-PDQ-15, which is an acid generator and quencher used for the resist material, are shown below.

Chemical formula

[0215]

Chemical formula

[0216]

Chemical formula

[0217] [Chemical formula]

[0218] [Chemical formula]

[0219] [Chemical formula]

[0220] [Chemical formula]

[0221] [Synthesis Example] Synthesis of Base Polymers (Polymers P-1 to P-4) Combined each monomer and carried out copolymerization reaction in THF as a solvent, put it into methanol, washed the precipitated solid with hexane, then isolated and dried it to obtain base polymers (Polymers P-1 to P-4) with the following compositions. The compositions of the obtained base polymers were 1 Confirmed by 1H-NMR for Mw and Mw / Mn by GPC (solvent: THF, standard: polystyrene). [Chemical formula]

[0222] [Examples 1 to 20, Comparative Examples 1 to 3] Preparation and Evaluation of Resist Materials (1) Preparation of Resist Materials A solution in which each component was dissolved with the composition shown in Table 1 was filtered through a 0.2 μm size filter to prepare a resist material.

[0223] In Table 1, each component is as follows. Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) EL (ethyl lactate) DAA (diacetone alcohol)

[0224] Comparative acid generators: cPAG-1, cPAG-PDQ-1

Chem.

[0225] Blended acid generator: bPAG-1

Chem.

[0226] Comparative quencher: cPDQ-1

Chem.

[0227] (2) EUV Lithography Evaluation Each resist material shown in Table 1 was spin-coated on a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content: 43% by mass) manufactured by Shin-Etsu Chemical Co., Ltd. was formed with a film thickness of 20 nm, and prebaked at 105 °C for 60 seconds using a hot plate to produce a resist film with a film thickness of 40 nm. The resist film was exposed using an EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.7, dipole illumination) manufactured by ASML, PEB was performed at the temperature described in Table 1 for 60 seconds on a hot plate, and development was performed for 30 seconds with a 2.38% by mass TMAH aqueous solution to form a line and space with a pitch of 32 nm and a line width of 16 nm. Examples 1 to 19 and Comparative Examples 1 and 2 are positive resist materials, and Examples 20 and Comparative Example 3 are negative resist materials. Using a length measurement SEM (CG6300) manufactured by Hitachi High-Tech Corporation, the exposure dose at which a line pattern was formed with a dimension of 16 nm ± 1.6 nm was determined, and the LWR at this exposure dose was measured. The results are shown in Table 1.

[0228]

Table 1

[0229] From the results shown in Table 1, it was found that the resist material of the present invention containing a divalent anion having a sulfonate anion structure directly bonded to an aromatic group substituted with an iodine atom and a carboxylate anion structure bonded to the aromatic group directly or via a linking group containing one or more atoms, and a bis-onium salt containing an onium cation, is highly sensitive and has good LWR.

Claims

1. A resist material comprising a divalent anion having a sulfonate anion structure directly bonded to an aromatic group substituted with an iodine atom and a carboxylate anion structure bonded to the aromatic group directly or via a linking group containing one or more atoms, and a bis-onium salt containing an onium cation.

2. The resist material according to claim 1, wherein the bis-onium salt is represented by the following formula (1): 【Chemistry 1】 (In the formula, p is an integer of 1 to 5, and q is an integer of 0 to 7. X 1 ~X 3 are each independently a single bond, an ether bond, an ester bond or an amide bond. R 1 ~R 3 are each independently a single bond or a hydrocarbylene group having 1 to 30 carbon atoms, and the hydrocarbylene group may contain at least one atom selected from an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom. 1 ~R 3 The upper limit of the total number of carbon atoms is 30. R 4 represents a hydrogen atom, a hydroxy group, a carboxy group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, a nitro group, a cyano group, a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbyloxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbylcarbonyloxy group having 2 to 20 carbon atoms, a hydrocarbylsulfonyloxy group having 1 to 20 carbon atoms, -N(R 4A )-C(=O)-R 4B , -N(R 4A )-C(=O)-O-R 4B Or -N(R 4A )-S(=O) 2 -R 4B The hydrocarbyl group, hydrocarbyloxy group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may contain at least one selected from a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydroxy group, an amino group, an ester bond, an ether bond, a urethane bond, a urea bond, a carbonate bond, an amide bond, a sulfonate ester bond, a carbonyl group, a sulfide group, and a sulfonyl group. 4A is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and the saturated hydrocarbyl group may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. 4B is an aliphatic hydrocarbyl group having 1 to 16 carbon atoms or an aryl group having 6 to 12 carbon atoms, which may contain a halogen atom, a hydroxy group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. Ar is a (p+q+1)-valent aromatic hydrocarbon group having 6 to 16 carbon atoms. M + is a sulfonium cation or an iodonium cation.

3. The resist material according to claim 1 , further comprising a base polymer.

4. The resist material according to claim 3 , wherein the base polymer comprises a repeating unit represented by the following formula (a1) or (a2): 【Chemistry 2】 (In the formula, R A are each independently a hydrogen atom or a methyl group. Y 1 represents a single bond, a phenylene group or naphthylene group, or a linking group having 1 to 12 carbon atoms containing at least one bond selected from an ester bond, an ether bond and a lactone ring, and the phenylene group, naphthylene group and linking group may have at least one bond selected from a hydroxy group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms and a saturated hydrocarbylcarbonyloxy group having 2 to 8 carbon atoms. Y 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond or an ester bond. R 11 and R 12 are each independently an acid labile group. R 13 represents a saturated hydrocarbyl group having 1 to 4 carbon atoms, a halogen atom, a saturated hydrocarbylcarbonyl group having 2 to 5 carbon atoms, a cyano group, or a saturated hydrocarbyloxycarbonyl group having 2 to 5 carbon atoms. R 14 is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the alkanediyl group may contain an ether bond or an ester bond. a is an integer from 0 to 4.

5. 5. The resist material of claim 4 which is a chemically amplified positive resist material.

6. 4. The resist material of claim 3, wherein the base polymer does not contain an acid labile group.

7. The resist material of claim 6 which is a chemically amplified negative resist material.

8. The resist material according to claim 1, further comprising an organic solvent.

9. The resist material according to claim 1, further comprising a quencher.

10. The resist material according to claim 1, further comprising an acid generator.

11. The resist material according to claim 1, further comprising a surfactant.

12. A pattern forming method comprising the steps of: forming a resist film on a substrate using the resist material according to any one of claims 1 to 11; exposing the resist film to high-energy radiation; and developing the exposed resist film using a developer.

13. 13. The pattern forming method according to claim 12, wherein the high-energy radiation is an ArF excimer laser beam having a wavelength of 193 nm, a KrF excimer laser beam having a wavelength of 248 nm, an electron beam, or an extreme ultraviolet ray having a wavelength of 3 to 15 nm.

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