Onium salt type monomer, polymer, chemically amplified resist composition, and pattern forming process

Abstract

Onium salt type monomer having the following formula (a1) or (a2).

Description

Technology Field

[0001] The present invention relates to an onium salt type monomer, a polymer, a chemical amplification resist composition, and a pattern forming method. Background Technology

[0002] To meet the demands for high integration and high speed in LSIs, the miniaturization of pattern rules is progressing rapidly. The expansion of the flash memory market and the increase in memory capacity are driving this miniaturization. As a cutting-edge miniaturization technology, mass production of microelectronic 65 nm node devices using ArF lithography is underway. Preparations for mass production of 45 nm node devices using next-generation ArF immersion lithography are in progress. Candidates for the next-generation 32 nm node include liquids with a higher refractive index than water, immersion lithography using ultra-high NA lenses combining high-refractive-index lenses and high-refractive-index resist films, EUV lithography with a wavelength of 13.5 nm, and dual exposure of ArF lithography, all of which are currently under active review.

[0003] As pattern features become finer and approach the diffraction limit, light contrast decreases. Due to this decrease in light contrast, in positive-type resist films, the resolution of hole patterns and trench patterns, as well as the focus margin, deteriorates.

[0004] With the miniaturization of pattern features, the edge roughness (LWR) of line patterns and the dimensional uniformity (CDU) of hole patterns are becoming problematic. The influence of base polymers and acid-generating agents on these factors, as well as the influence of acid diffusion, has been pointed out. As the resist film becomes thinner, LWR tends to increase. The deterioration of LWR due to thinning as miniaturization progresses is a serious problem.

[0005] For EUV lithography resists, high sensitivity, high resolution, and low LWR must be achieved simultaneously. Shortening the acid diffusion distance reduces LWR but lowers sensitivity. For example, lowering the PEB temperature results in a smaller LWR but lower sensitivity. Increasing the amount of quencher also results in a smaller LWR but lower sensitivity. It is necessary to overcome the trade-off relationship between sensitivity and LWR.

[0006] Patent Document 1 discloses a resist compound comprising repeating units derived from an onium salt of a sulfonic acid having polymerizable unsaturated bonds. Since such so-called polymer-bonded acid-generating agents generate polymeric sulfonic acid upon exposure, the acid diffusion distance is very short. Sensitivity can also be improved by increasing the proportion of the acid-generating agent. In the case of additive-type acid-generating agents, increasing the amount of the acid-generating agent increases sensitivity, but also increases the acid diffusion distance. Since acid diffuses non-uniformly, increased acid diffusion leads to the deterioration of LWR and CDU. Polymer-bonded acid-generating agents possess high capability in terms of the balance between sensitivity, LWR, and CDU.

[0007] Since iodine atoms have very high absorption for EUV with a wavelength of 13.5 nm, it has been confirmed that they generate secondary electrons during exposure, and they are attracting attention in the field of EUV lithography. Patent Document 2 discloses a photogenerator having an iodine atom in an anion, and Patent Document 3 discloses a photogenerator containing a polymerizable group having an iodine atom in an anion. Although it has been confirmed that iodine atoms improve lithography performance to some extent, iodine atoms do not have high solubility in organic solvents and may precipitate in the solvent. Prior art literature

[0008] Patent Document 1: JP 4425776 Patent Document 2: JP 6720926 Patent Document 3: JP 6973274 The problem to be solved

[0009] In the field of acid-catalyzed chemical amplification resist compositions, there is a demand for a resist composition that is more sensitive, has improved LWR of line patterns and CDU of hole patterns, and has excellent etching resistance after pattern formation.

[0010] The present invention is made in consideration of the above circumstances, and aims to provide an onium salt-type monomer for a chemical amplification resist composition that has excellent solvent solubility, high sensitivity and high contrast, excellent lithography performance such as exposure latitude (EL), LWR, CDU, and depth of focus (DOF), excellent resistance to pattern collapse and excellent etching resistance in the formation of fine patterns, a polymer comprising repeating units derived from said onium salt-type monomer, a chemical amplification resist composition comprising said polymer, and a method for forming a pattern using said chemical amplification resist composition. means of solving the problem

[0011] As a result of repeated careful examination to achieve the above objective, the inventors have discovered that by using a polymer comprising repeating units derived from a sulfonium salt or an iodonium salt, which includes an anion having a linker structure between the aromatic ring and the fluorosulfonic acid structure, as a polymer-linked acid-generating agent, a fluorosulfonic acid anion having an aromatic ring substituted with a vinyl group and an iodine atom, it is possible to obtain a chemical amplification resist composition that is highly sensitive, has improved LWR and CDU, has high contrast and high resolution, and has excellent etching resistance.

[0012] The present invention provides the following onium salt type monomer, polymer, chemical amplification resist composition, and pattern forming method.

[0013] 1. Onium salt type monomer having the following formula (a1) or (a2):

[0014]

[0015] In the expression, n1 is 0 or 1, n2 is an integer from 1 to 6, and n3 is an integer from 0 to 4, provided that when n1 is 0, the sum of n2+n3 is 4 or less, and when n1 is 1, the sum of n2+n3 is 6 or less, and n4 is an integer from 0 to 4,

[0016] R A Each is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group, and

[0017] C1-C where R may each independently contain heteroatoms 20 Hydrocarbilgi,

[0018] L A and L B Each is independently a single bond, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, or a carbamate bond, and

[0019] X L C1-C that may each independently contain heteroatoms 40 It is a hydrocarbylene group, and

[0020] Q 1 and Q 2 Each is independently a hydrogen atom, a fluorine atom, or a C1-C6 fluorinated saturated hydrocarbyl group, and

[0021] Q 3 and Q 4 Each is independently a fluorine atom or a C1-C6 fluorinated saturated hydrocarbyl group, and

[0022] R 1 ~R 5 C1-C that may each independently contain heteroatoms 30 It is hydrocarbilic, and R 1 and R 2 They may combine together to form a ring with the sulfur atoms to which they combine.

[0023] 2. An onium salt-type monomer of formula (a1) having the following formula (a1-1), and an onium salt-type monomer of formula (a2) having the following formula (a2-1):

[0024]

[0025] During the meal, R A , R, L A , L B , X L , Q 1 ~Q 4 , n2~n4 and R 1 ~R 5 is as defined above.

[0026] 3. An onium salt-type monomer of formula (a1-1) having the following formula (a1-2), and an onium salt-type monomer of formula (a2-1) having the following formula (a2-2):

[0027]

[0028] During the meal, R A , R, L A , L B , X L , Q 1 , Q 2 , n2~n4 and R 1 ~R 5 is as defined above.

[0029] 4. An onium salt type monomer of formula (a1-2) having the following formula (a1-3), and an onium salt type monomer of formula (a2-2) having the following formula (a2-3):

[0030]

[0031] During the meal, R A , R, X L , Q 1 , Q 2 , n2~n4 and R 1 ~R 5 is as defined above.

[0032] 5. A polymer comprising repeating units derived from any one of 1 to 4 onium salt-type monomers.

[0033] 6. A polymer of 5 further comprising a repeating unit having the following formula (b1) or (b2):

[0034]

[0035] During the meal, R A Each is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group, and

[0036] X 1 Silver single bond, phenylene group, naphthylene group, *-C(=O)-OX 11 - or *-C(=O)-NH-X 11 - and, the phenylene group or naphthylene group may include a fluorine atom, C1-C 10 It may be substituted with an alkoxy group or a halogen atom, and X 11 C1-C 10 The saturated hydrocarbylene group, phenylene group, or naphthylene group, wherein the saturated hydrocarbylene group may include a hydroxyl group, an ether bond, an ester bond, or a lactone ring, and

[0037] X 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, and

[0038] The asterisk (*) indicates a bonding point with a carbon atom in the main chain,

[0039] AL 1 and AL 2 Each is independently a wildfire stable period, and

[0040] R 11 C1-C may contain halogen atoms, cyano groups, and heteroatoms. 20 C1-C that may contain hydrocarbyl groups and heteroatoms 20 C2-C that may contain hydrocarbyloxy groups and heteroatoms 20Hydrocarbylcarbonyl group, C2-C that may contain heteroatoms 20 C2-C that may contain a hydrocarbylcarbonyloxy group or a heteroatom 20 It is a hydrocarbyloxycarbonyl group, and

[0041] a is an integer from 0 to 4.

[0042] 7. A polymer of 5 or 6 further comprising a repeating unit having the following formula (c1):

[0043]

[0044] During the meal, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group, and

[0045] Y 1 is a single bond, *-C(=O)-O- or *-C(=O)-NH-, and the asterisk (*) indicates the bonding point with a carbon atom in the main chain, and

[0046] R 21 C1-C may contain halogen atoms, nitro groups, cyano groups, and heteroatoms. 20 C1-C that may contain hydrocarbyl groups and heteroatoms 20 C2-C that may contain hydrocarbyloxy groups and heteroatoms 20 Hydrocarbylcarbonyl group, C2-C that may contain heteroatoms 20 C2-C that may contain a hydrocarbylcarbonyloxy group or a heteroatom 20 It is a hydrocarbyloxycarbonyl group, and

[0047] c is an integer from 1 to 4, and d is an integer from 0 to 3, provided that the sum of c+d is 1 or greater and 5 or less.

[0048] 8. Any one of 5 to 7 polymers further comprising a repeating unit having the following formula (d1):

[0049]

[0050] During the meal, RA is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group, and

[0051] Z 1 Silver single bond, phenylene group, naphthylene group, *-C(=O)-OZ 11 - or *-C(=O)-NH-Z 11 - and, the phenylene group or naphthylene group may include a fluorine atom, C1-C 10 It may be substituted with an alkoxy group or a halogen atom, and an asterisk (*) indicates a bonding point with a carbon atom in the main chain, and Z 11 C1-C 10 The saturated hydrocarbylene group, phenylene group, or naphthylene group, wherein the saturated hydrocarbylene group may include a hydroxyl group, an ether bond, an ester bond, or a lactone ring, and

[0052] R 31 A C1-C comprising at least one structure selected from a hydrogen atom, or a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sulfone ring, and a carboxylic acid anhydride (-C(=O)-OC(=O)-). 20 It is.

[0053] 9. (A) A chemical amplification resist composition comprising a base polymer comprising any one of 5 to 8 polymers.

[0054] 10. (B) A chemical amplification resist composition of 9 further comprising an organic solvent.

[0055] 11. (C) Chemical amplification resist composition of 9 or 10 further comprising a quencher.

[0056] 12. (D) A chemical amplification resist composition of any one of 9 to 11 further comprising an acid-generating agent.

[0057] 13. (E) A chemical amplification resist composition of any one of 9 to 12 further comprising a surfactant.

[0058] 14. (F) A chemical amplification resist composition of any one of 9 to 13 further comprising a dissolution inhibitor.

[0059] 15. A pattern forming method comprising the steps of: applying a chemical amplification resist composition of any one of 9 to 14 onto a substrate to form a resist film; exposing the resist film to high-energy rays; and developing the exposed resist film in a developer.

[0060] 16. A pattern forming method of 15 in which the high-energy line is an ArF excimer laser having a wavelength of 193 nm, a KrF excimer laser having a wavelength of 248 nm, EB, or EUV having a wavelength of 3 to 15 nm. Effects of the invention

[0061] A resist film comprising a polymer containing repeating units derived from an onium salt-type monomer represented by formula (a1) or (a2) has good solvent solubility and is characterized by a short acid diffusion distance due to the large amount of iodine atoms. This prevents a decrease in resolution caused by the blurring of acid diffusion, thereby improving LWR and CDU. Since the absorption amount of EUV at a wavelength of 13.5 nm by iodine atoms is very large, iodine atoms generate secondary electrons during exposure, resulting in high sensitivity. This makes it possible to construct a chemically amplified resist composition that is highly sensitive and has improved LWR and CDU. Aromatic rings act as groups exhibiting good etching resistance and are suitable for forming fine patterns. Specific details for implementing the invention

[0062] Onium salt type monomer

[0063] The onium salt type monomer of the present invention is represented by the following formula (a1) or (a2).

[0064]

[0065] In formula (a1) or (a2), n1 is 0 or 1. The onium salt-type monomer has a benzene ring when n1 is 0 and a naphthalene ring when n1 is 1, but from the perspective of solvent solubility, it is preferable for n1 to be 0. n2 is an integer from 1 to 6. As the number of iodine atoms in the anionic structure increases, the amount of absorption for EUV increases, but solvent solubility becomes insufficient, and there is a risk of precipitation in the resist composition. Therefore, it is preferable for n2 to be 1 to 3, and more preferable for it to be 1 or 2. n3 is an integer from 0 to 4, preferably an integer from 0 to 2, and more preferable for it to be 0 or 1. However, when n1 is 0, the sum of n2+n3 is 4 or less, and when n1 is 1, the sum of n2+n3 is 6 or less, and n4 is an integer from 0 to 4, preferably an integer from 0 to 3, and more preferably 1.

[0066] In equation (a1) or (a2), R A Each is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Among these, it is preferable that it be a hydrogen atom and a methyl group, and it is more preferable that it be a hydrogen atom.

[0067] In formula (a1) or (a2), it is preferable that the iodine atom in the anionic aromatic ring be bonded to a carbon atom other than the carbon atom adjacent to the carbon atom to which the vinyl group is bonded. Since the iodine atom is an element with a large atomic radius, bonding the iodine atom to the carbon atom adjacent to the vinyl group can cause steric hindrance during polymerization, which may lead to a decrease in the conversion rate of the polymerization reaction.

[0068] In formula (a1) or (a2), R may each independently contain a C1-C 20It is a hydrocarbyl group. The above hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Examples include C1-C groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, heptadecyl, octadecyl, nonadecyl, and icosyl. 20 Alkyl groups; C3-C groups such as cyclopropyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, 4-methylcyclohexyl group, cyclohexylmethyl group, norbornyl group, adamantyl group, etc. 20 Cyclic saturated hydrocarbyl group; C2-C groups such as vinyl group, allyl group, propenyl group, butenyl group, hexenyl group, etc. 20 C3-C groups such as alkenyl groups; cyclohexenyl groups, etc. 20 Cyclic unsaturated hydrocarbyl group; C2-C groups such as phenyl group, naphthyl group, etc. 20 Aryl groups; C7-C groups such as benzyl groups, 1-phenylethyl groups, 2-phenylethyl groups, etc. 20 Examples include aryl groups; combinations thereof. Among these, preferably, it is an aryl group. Some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, or halogen atoms, and some of the -CH2- constituting the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, or nitrogen atoms, and as a result, the hydroxycarbyl group may include a hydroxyl 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 sulfonic acid ester bond, a carbonate bond, a lactone ring, a sulfone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0069] In equation (a1) or (a2), L A and L BEach is independently a single bond, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, or a carbamate bond. Among these, it is preferable that it be a single bond, an ether bond, or an ester bond.

[0070] In either equation (a1) or (a2), X L C1-C that may each independently contain heteroatoms 40 It is a hydrocarbylene group. The above hydrocarbylene group may be linear, branched, or cyclic, and examples include an alkanedyl group, a cyclic saturated hydrocarbylene group, etc. Examples of the above heteroatoms include oxygen atoms, nitrogen atoms, sulfur atoms, etc.

[0071] C1-C that may contain heteroatoms 40 Hydrocarbylen group X L As such, it is preferable to represent it as follows. In the following formulas, the asterisk (*) represents L A and L B Indicates the connection point with.

[0072]

[0073]

[0074] Among these, X L -0~X L -3, X L -29~X L -34 and X L -47~X L -49 is desirable, and X L -0~X L -2, X L -29, X L -47 is more desirable.

[0075] In equation (a1) or (a2), Q 1 and Q 2 Each is independently a hydrogen atom, a fluorine atom, or a C1-C6 fluorinated saturated hydrocarbyl group. As for the fluorinated saturated C1-C6 hydrocarbyl group, a trifluoromethyl group is preferred.

[0076] In equation (a1) or (a2), Q 3 and Q 4 Each is independently a fluorine atom or a C1-C6 fluorinated saturated hydrocarbyl group. As for the fluorinated saturated C1-C6 hydrocarbyl group, a trifluoromethyl group is preferred. Q 3 and Q 4 As for that, it is more preferable that it be a fluorine atom.

[0077] In equation (a1) or (a2), the substructure -[C(Q 1 )(Q 2 )] n4 -C(Q 3 )(Q 4 )-SO3 - Examples are preferably shown below, but substructures are not limited to these. In the following formulas, the asterisk (*) indicates L B Indicates the connection point with.

[0078]

[0079] Among these, Acid-1 to Acid-7 are preferred, and Acid-1 to Acid-3, Acid-6 and Acid-7 are more preferred.

[0080] The onium salt type monomer of formula (a1) is preferably represented by the following formula (a1-1), and the onium salt type monomer of formula (a2) is preferably represented by the following formula (a2-1).

[0081]

[0082] During the meal, R A , R, L A , L B , X L , Q 1 ~Q 4 , n2~n4 and R 1 ~R 5 is as defined above.

[0083] The onium salt type monomer of formula (a1-1) is preferably represented by the following formula (a1-2), and the onium salt type monomer of formula (a2-1) is preferably represented by the following formula (a2-2).

[0084]

[0085] During the meal, R A , R, L A , L B , X L , Q 1 , Q 2 , n2~n4 and R 1 ~R 5 is as defined above.

[0086] As an onium salt type monomer of formula (a1-2), it is preferable to be represented by the following formula (a1-3), and as an onium salt type monomer of formula (a2-2), it is preferable to be represented by the following formula (a2-3).

[0087]

[0088] During the meal, R A , R, X L , Q 1 , Q 2 , n2~n4 and R 1 ~R 5 is as defined above.

[0089] Examples of anions for the sulfonium salt represented by formula (a1) and the iodonium salt represented by formula (a2) include those shown below, but are not limited thereto. Among the following formulas, R A and Q 1 It is as defined above. The bonding positions of substituents on the directional ring are interchangeable.

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106] Among equations (a1) and (a2), R 1 ~R 5 C1-C that may each independently contain heteroatoms 30It is a hydrocarbyl group. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups; cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; alkenyl groups such as vinyl, allyl, propenyl, butenyl, and hexenyl groups; cyclic unsaturated hydrocarbyl groups such as cyclohexenyl groups; aryl groups such as phenyl, naphthyl, and thienyl groups; aryl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl groups; and combinations thereof. An aryl group is preferred. Some or all of the hydrogen atoms of the above hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the -CH2- constituting the above hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., and as a result, the above hydroxycarbyl group may include a hydroxyl 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 sulfone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0107] R 1 and R 2 They may combine together to form a ring with the sulfur atom to which they are bonded. Examples of sulfonium cations in formula (a1) include those represented by the following formula.

[0108]

[0109] In the formula, the asterisk (*) is R 3 It is the connection point with.

[0110] Examples of cations of the sulfonium salt represented by formula (a1) include those shown below, but are not limited to these.

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[0117]

[0118]

[0119]

[0120]

[0121]

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129] Examples of cations of iodium salts represented by formula (a2) include those shown below, but are not limited to these.

[0130]

[0131] Specific examples of the onium salt type monomer of the present invention include any combination of the anion and the cation.

[0132] The onium salt-type monomer represented by formula (a1) or (a2) can be synthesized in the same way as the synthesis of the sulfonium salt having a polymerizable anion of JP 5201363, but the synthesis method is not limited thereto.

[0133] polymer

[0134] The polymer of the present invention comprises a repeating unit derived from an onium salt-type monomer represented by formula (a1) (hereinafter also referred to as repeating unit (a1)) or a repeating unit derived from an onium salt-type monomer represented by formula (a2).

[0135] The polymer of the present invention is a polymer-linked photogenerator that functions as a photogenerator and also functions as a base polymer in a chemically amplified resist composition. Structural features of the polymer of the present invention include an aromatic ring directly linked to a main chain in which an anion is substituted with an iodine atom, and a linker structure between said aromatic ring and a fluorosulfonic acid structure. Since iodine atoms have a very high absorption of EUV at a wavelength of 13.5 nm, they generate secondary electrons during exposure, and high sensitivity is achieved as the energy of the secondary electrons is transferred to the acid generator. However, since iodine is not an element with high solvent solubility, if multiple iodine atoms are introduced to achieve high sensitivity, the iodine atoms may precipitate within the resist composition. By introducing a linker structure, lipid solubility is improved, allowing for uniform dissolution in the solvent. Furthermore, since an anion is directly linked to the main chain of the base polymer but an appropriate acid diffusion distance can be secured, excessive acid diffusion is suppressed, thereby improving the LWR of line patterns and CDU of hole patterns. In addition, the glass transition temperature (Tg) of the base polymer is improved because the main chain of the base polymer becomes rigid due to the presence of an aromatic ring directly connected to the main chain. It is thought that the base polymer is regularly arranged through the interaction of aromatic rings within or between base polymers (exhibiting a π-π stacking effect), thereby exhibiting resistance to pattern collapse with respect to the developer even during the formation of fine patterns. Excellent etching resistance is also exhibited during the etching process after the formation of fine patterns due to the presence of an aromatic ring directly connected to the main chain. Since these effects act synergistically, the polymer of the present invention is particularly suitable as a material for a chemically amplified positive type resist composition because excessive acid diffusion is suppressed, the LWR of line patterns and CDU of hole patterns are excellent, and pattern formation is possible where pattern collapse is unlikely to occur.

[0136] The above polymer may further include a repeating unit represented by the following formula (b1) (hereinafter also referred to as repeating unit (b1)) or a repeating unit represented by the following formula (b2) (hereinafter also referred to as repeating unit (b2)).

[0137]

[0138] Among equations (b1) and (b2), R A Each is independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

[0139] In equation (b1), X 1 Silver single bond, phenylene group, naphthylene group, *-C(=O)-OX 11 - or *-C(=O)-NH-X 11 - and, the phenylene group or naphthylene group may include a fluorine atom, C1-C 10 It may be substituted with an alkoxy group or a halogen atom. X 11 C1-C 10 The saturated hydrocarbylene group, phenylene group, or naphthylene group may include a hydroxyl group, an ether bond, an ester bond, or a lactone ring, and an asterisk (*) indicates a bonding point with a carbon atom of the main chain.

[0140] In equation (b2), X 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-. The asterisk (*) indicates a bonding point with a carbon atom in the main chain, and R 11 C1-C may contain halogen atoms, cyano groups, and heteroatoms. 20 C1-C that may contain hydrocarbyl groups and heteroatoms 20 C2-C that may contain hydrocarbyloxy groups and heteroatoms 20 Hydrocarbylcarbonyl group, C2-C that may contain heteroatoms 20 C2-C that may contain a hydrocarbylcarbonyloxy group or a heteroatom 20It is a hydrocarbyloxycarbonyl group, where a is an integer from 0 to 4, preferably 0 or 1.

[0141] Among equations (b1) and (b2), AL 1 and AL 2 Each is independently a wild fire stable. Examples of the above wild fire stables include those described in JP-A 2013-80033 and JP-A 2013-83821, but are not limited to these.

[0142] Typically, the above-mentioned acid-stable can be an example of a unit represented by the following formulas (AL-1) to (AL-3).

[0143]

[0144] In the formula, the asterisk (*) is the joint point.

[0145] Among equations (AL-1) and (AL-2), R L1 and R L2 C1-C each independently 40 It is a hydrocarbyl group and may contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, and iodine atoms. The hydrocarbyl group may be linear, branched, or cyclic. As for the hydrocarbyl group, C1-C 20 It is desirable to be hydrocarbyl.

[0146] In formula (AL-1), b is an integer from 0 to 10, and preferably an integer from 1 to 5.

[0147] In formula (AL-2), R L3 and R L4 Each is independently a hydrogen atom or C1-C 20 It is a hydrocarbyl group and may contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, and iodine atoms. The hydrocarbyl group may be linear, branched, or cyclic. R L2 , R L3 and R L4Any two of them bond together with the carbon atom they bond to, or with a carbon atom or an oxygen atom, to form a C3-C 20 A ring may be formed. As the above ring, C4-C 16 A ring shape is desirable, and a ring shape is particularly desirable.

[0148] In formula (AL-3), R L5 , R L6 and R L7 C1-C each independently 20 It is a hydrocarbyl group and may contain heteroatoms such as oxygen, sulfur, nitrogen, fluorine, and iodine atoms. The hydrocarbyl group may be linear, branched, or cyclic. R L5 , R L6 and R L7 Any two of them combine together with the carbon atom they bond to, forming a C3-C bond. 20 A ring may be formed. As the above ring, C4-C 16 A ring shape is desirable, and a ring shape is particularly desirable.

[0149] Examples of repetition units (b1) include those shown below, but are not limited to these. Among the following expressions, R A and AL 1 It is as defined above.

[0150]

[0151]

[0152]

[0153]

[0154] Examples of repetition units (b2) include those shown below, but are not limited to these. Among the following formulas, R A and AL 2 is as defined above.

[0155]

[0156]

[0157] The above base polymer preferably further comprises a repeating unit represented by the following formula (c1) (hereinafter also referred to as repeating unit (c)).

[0158]

[0159] In equation (c1), 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-, the asterisk (*) indicates the bonding point with a carbon atom in the main chain, and R 21 C1-C may contain halogen atoms, nitro groups, cyano groups, and heteroatoms. 20 C1-C that may contain hydrocarbyl groups and heteroatoms 20 C2-C that may contain hydrocarbyloxy groups and heteroatoms 20 Hydrocarbylcarbonyl group, C2-C that may contain heteroatoms 20 C2-C that may contain a hydrocarbylcarbonyloxy group or a heteroatom 20 It is a hydrocarbyloxycarbonyl group, where c is an integer from 1 to 4 and d is an integer from 0 to 3, provided that the sum of c+d is 1 or more and 5 or less.

[0160] Examples of repetition units (c) include those shown below, but are not limited to them. Among the following expressions, R A is as defined above.

[0161]

[0162]

[0163]

[0164] The above base polymer preferably further comprises a repeating unit (hereinafter also referred to as repeating unit (d)) represented by the following formula (d1).

[0165]

[0166] In equation (d1), R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group, and Z 1 Silver single bond, phenylene group, naphthylene group, *-C(=O)-OZ 11 - or *-C(=O)-NH-Z 11 - Or, the above phenylene group or naphthylene group may include a fluorine atom, C1-C 10 It may be substituted with an alkoxy group or a halogen atom, and an asterisk (*) indicates a bonding point with a carbon atom in the main chain, and Z 11 C1-C 10 is a saturated hydrocarbylene group, a phenylene group, or a naphthylene group, and the saturated hydrocarbylene group may include a hydroxyl group, an ether bond, an ester bond, or a lactone ring, and R 31 A C1-C comprising at least one structure selected from a hydrogen atom, or a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sulfone ring, and a carboxylic acid anhydride (-C(=O)-OC(=O)-). 20 It is.

[0167] Examples of repetition units (d) include those shown below, but are not limited to them. Among the following expressions, R A is as defined above.

[0168]

[0169]

[0170]

[0171]

[0172]

[0173]

[0174]

[0175]

[0176]

[0177]

[0178]

[0179]

[0180] Among the repeating units (c) or (d), for ArF lithography, a unit having a lactone ring as a polar group is preferred, and for KrF, EB, or EUV lithography, a unit having a phenol group as a polar group is preferred.

[0181] The above polymer may further include a repeating unit (hereinafter also referred to as repeating unit (e)) having a structure in which a hydroxyl group is protected by an acid-unstable group. The repeating unit (e) is not particularly limited as long as it has one or more structures in which a hydroxyl group is protected by a protecting group, and the protecting group decomposes to form a hydroxyl group upon the action of an acid. A repeating unit represented by the following formula (e1) is preferred.

[0182]

[0183] In equation (e1), R A is as defined above. R 41 C1-C that may contain heteroatoms 30 It is an (e+1) valence hydrocarbon group of R 42 is a wildfire stable period. e is an integer from 1 to 4.

[0184] In Equation (e1), wildfire stability period R 42 It deprotects through the action of acid, generating a hydroxyl group. R 42The structure is not particularly limited, and an acetal structure, a ketal structure, an alkoxycarbonyl group, an alkoxymethyl group represented by the following formula (e2), etc. are preferred, and an alkoxymethyl group represented by the following formula (e2) is more preferred.

[0185]

[0186] In the expression, the asterisk (*) indicates a joint point, and R 43 C1-C 15 It is hydrocarbilgi.

[0187] Forest fire stabilization period R 42 Examples of the alkoxymethyl group and repeating unit (e) represented by formula (e2) include those exemplified in the repeating unit (d) of JP-A 2020-111564.

[0188] In addition to the above units, the base polymer may further include repeating units (f) derived from indene, benzofuran, benzothiophene, acenaphtylene, chromone, coumarin, and norbornadiene or derivatives thereof. Examples of monomers imparting repeating units (f) include those listed below, but are not limited thereto.

[0189]

[0190] In addition, the base polymer may further include repeating units (g) derived from styrene, indan, vinylpyridine, vinylcarbazole, or derivatives thereof.

[0191] In the polymer of the present invention, the content ratio of repeating units (a1), (a2), (b1), (b2), (c), (d), (e), (f) and (g) is preferably 0 <a1≤0.4, 0<a2≤0.4, 0<b1≤0.8, 0≤b2≤0.8, 0<c≤0.6, 0≤d≤0.6, 0≤e≤0.3, 0≤f≤0.3 및 0≤g≤0.3이고; 더욱 바람직하게는 0<a1≤0.3, 0<a2≤0.3, 0<b1≤0.7, 0≤b2≤0.7, 0<c≤0.5, 0≤d≤0.5, 0≤e≤0.2, 0≤f≤0.2 및 0≤g≤0.2이다.

[0192] The weight average molecular weight (Mw) of the above polymer is preferably in the range of 1,000 to 500,000, and more preferably in the range of 3,000 to 100,000. When Mw is in this range, sufficient etching resistance is secured, and there is no concern about a decrease in resolution due to the inability to secure a difference in dissolution rate before and after exposure. In the present invention, Mw is a polystyrene equivalent measurement value by gel permeation chromatography (GPC) using tetrahydrofuran (THF) or N,N-dimethylformamide (DMF) as a solvent.

[0193] Since the influence of the dispersion degree (Mw / Mn) of the above base polymer tends to increase as the pattern rule becomes finer, it is preferable that the Mw / Mn be narrowly dispersed to 1.0 to 2.0 in order to obtain a resist composition suitable for fine patterning with fine feature dimensions. If the Mw / Mn is within the above range, there is a small fraction of low molecular weight or high molecular weight, so there is no risk of foreign matter being visible on the pattern or the shape of the pattern deteriorating after exposure and development.

[0194] As a method for synthesizing the above polymer, for example, one or more monomers selected from monomers that impart the repeating unit described above are dissolved in an organic solvent, a radical polymerization initiator is added, and the mixture is heated to polymerize.

[0195] Examples of organic solvents that can be used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, dioxane, cyclohexane, cyclopentane, methyl ethyl ketone (MEK), propylene glycol monomethyl ether acetate (PGMEA), γ-butyrolactone (GBL), etc. Examples of polymerization initiators used at this time include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropyrronate), 1,1'-azobis(1-acetoxy-1-phenylethane), benzoyl peroxide, lauroyl peroxide, etc. The amount of these initiators added is preferably 0.01 to 25 mol% relative to the total amount of monomers. The reaction temperature is preferably 50 to 150°C, and more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours, and more preferably 2 to 12 hours from the perspective of production efficiency.

[0196] The polymerization initiator may be added to the monomer solution and supplied to the reaction vessel. Alternatively, a polymer initiator solution may be prepared separately from the monomer solution, and the monomer and initiator solutions may be supplied to the reaction vessel independently. Since there is a possibility that the polymerization reaction may proceed due to radicals generated from the initiator during the waiting time, thereby producing ultra-high molecular weight compounds, it is desirable to prepare and dropwise the monomer solution and the initiator solution independently from the perspective of quality control. The acid instability group may be used as is, introduced into the monomer, or may be protected or partially protected after polymerization. To adjust the molecular weight, known chain transfer agents such as dodecyl mercaptan or 2-mercaptoethanol may be used. The appropriate amount of the chain transfer agent is preferably 0.01 to 20 mol% relative to the total amount of monomers to be polymerized.

[0197] When copolymerizing monomers containing hydroxyl groups, the hydroxyl groups may be substituted with acetal groups that are easily deprotected by acid, typically ethoxyethoxy groups, before polymerization, and deprotected by a weak acid and water after polymerization. Alternatively, the hydroxyl groups may be substituted with acetyl groups, formyl groups, pivaloyyl groups, or similar groups before polymerization, and alkaline hydrolysis may be performed after polymerization.

[0198] When copolymerizing hydroxystyrene or hydroxyvinylnaphthalene, alternative methods are possible. Specifically, instead of hydroxystyrene or hydroxyvinylnaphthalene, acetoxystyrene or acetoxyvinylnaphthalene may be used, and the acetoxy groups may be deprotected by alkaline hydrolysis after polymerization to convert the polymer product into polyhydroxystyrene or hydroxypolyvinylnaphthalene.

[0199] As the base for alkaline hydrolysis, water ammonia, triethylamine, etc., may be used. The reaction temperature is preferably -20 to 100°C, more preferably 0 to 60°C. The reaction time is 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0200] The amount of monomer in the above monomer solution may be appropriately set to a desirable content ratio of the aforementioned repeating unit.

[0201] The reaction solution obtained by the polymerization reaction may be used as the final product. Alternatively, the polymer may be recovered in powder form through a purification process, such as a reprecipitation method in which the polymer solution is added to a solvent to precipitate the polymer as a powder, and the polymer powder may be used as the final product. From the perspective of work efficiency and quality stabilization, it is preferable to handle the polymer solution obtained by dissolving the powdered polymer obtained from the purification process in a solvent as the final product.

[0202] The solvents that can be used at this time are described in paragraphs

[0144] to

[0145] of JP-A 2008-111103. Examples of solvents include ketones such as cyclohexanone and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; and ethers such as propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether. Examples include esters such as PGMEA, 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 mono-tert-butyl ether acetate; lactones such as GBL; alcohols such as diacetone alcohol (DAA); and high-boiling point alcohols such as diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, and 1,3-butanediol, which may be used alone or in combination.

[0203] Among the above polymer solution, the concentration of the polymer is preferably 0.01 to 30 weight%, and more preferably 0.1 to 20 weight%.

[0204] Before use, it is desirable to filter the above reaction solution or polymer solution. Filtration is effective in terms of quality stabilization as it removes foreign substances or gels that may cause defects.

[0205] As the material of the filter on which filtration is performed, materials such as fluorocarbon-based, cellulose-based, nylon-based, polyester-based, or hydrocarbon-based materials are suitable. For the filtration of the chemical amplification resist composition, a filter formed from a fluorocarbon-based material, commonly known as Teflon®, a hydrocarbon-based material such as polyethylene and polypropylene, or nylon is preferred. The pore diameter of the filter can be appropriately selected to match the target cleanliness, but the pore diameter of the filter is preferably 100 nm or less, and more preferably 20 nm or less. A filter may be used alone or a combination of multiple filters may be used. The filtration method may involve passing the solution through only once, but it is preferable to repeat the filtration step by flowing the solution in a circulating manner. The filtration step may be performed in any order, at any stage, and any number of times during the polymer manufacturing process. It may be possible to filter the polymerized reaction solution or the polymer solution, and it is preferable to filter both.

[0206] Chemical amplification resist composition

[0207] (A) Base polymer

[0208] The chemical amplification resist composition of the present invention comprises (A) a base polymer comprising the polymer defined above.

[0209] The above polymer may be used alone or as a mixture of two or more polymers with different composition ratios, Mw and / or Mw / Mn. (A) In addition to the polymer defined above, the base polymer may include a hydrogenation product of a ring-opening metathesis polymer, as described in JP-A 2003-66612.

[0210] (B) Organic solvent

[0211] The chemical amplification resist composition of the present invention may include (B) an organic solvent. (B) The organic solvent is not particularly limited as long as it is capable of dissolving the above component (A) and the component described below. Examples of such organic solvents include ketones such as cyclopentanone, cyclohexanone, and methyl-2-n-pentyl ketone; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol; keto-alcohols such as DAA; and ethers such as PGME, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether. Esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol mono-tert-butyl ether acetate; lactones such as GBL are suitable, and these may be used alone or in combination.

[0212] Among the above organic solvents, 1-ethoxy-2-propanol, PGMEA, cyclohexanone, GBL, DAA, and mixtures thereof are preferred, as they have particularly excellent solubility of the base polymer (A).

[0213] In the chemical amplification resist composition of the present invention, the content of the organic solvent (B) is preferably 200 to 5,000 parts by weight and more preferably 400 to 3,500 parts by weight with respect to 80 parts by weight of the base polymer (A). The organic solvent (B) may be used alone or in combination.

[0214] (C) Kencher

[0215] The chemical amplification resist composition of the present invention may include (C) a quencher. In the present invention, a quencher refers to a compound that helps form a desired pattern by trapping acid generated from a photogenerative agent in the chemical amplification resist composition during exposure, thereby preventing the diffusion of acid into an unexposed area.

[0216] As a quencher (C), an onium salt represented by the following formulas (1) and (2) is useful.

[0217]

[0218] In Equation (1), R q1 C1-C may contain hydrogen atoms or heteroatoms. 40 It is a hydrocarbyl group, but excludes hydrocarbyl groups in which the hydrogen atom bonded to the carbon atom at the α position of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group. In Formula (2), R q2 C1-C may contain hydrogen atoms or heteroatoms 40 It is hydrocarbilgi.

[0219] C1-C 40 Hydrocarbilgi R q1 Examples include C1-C groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl groups. 40 Alkyl group; 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 C3-C groups such as decyl and adamantyl groups 40 Cyclic saturated hydrocarbyl group; C6-C groups such as phenyl group, naphthyl group, anthracenyl group, etc. 40Examples include aryl groups. Some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- constituting the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, the hydrocarbyl group may include a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sulfone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0220] Hydrocarbilgi R q2 As an example, R q1 Examples of such groups include the ones exemplified above, fluorinated saturated hydrocarbyl groups such as trifluoromethyl groups and trifluoroethyl groups, and fluorinated aryl groups such as pentafluorophenyl groups and 4-trifluoromethylphenyl groups.

[0221] Examples of anions of the onium salt represented by formula (1) include those shown below, but are not limited to these.

[0222]

[0223]

[0224] Examples of anions of the onium salt represented by formula (2) include those shown below, but are not limited to these.

[0225]

[0226]

[0227] Among equations (1) and (2), Mq +is an onium cation. As the onium cation, the sulfonium cation in formula (a1), the iodonium cation in formula (a2), or the ammonium cation represented by the following formula (3) is preferred.

[0228]

[0229] In Equation (3), R q3 ~R q6 C1-C that may each independently contain heteroatoms 40 It is hydrocarbyl. R q3 and R q4 They arbitrarily combine with each other to form a ring together with the nitrogen atom to which they combine. As the hydrocarbyl group, the hydrocarbyl group R in formulas (a1) and (a2) is. 1 ~R 5 Examples such as those exemplified above can be cited.

[0230] Examples of ammonium cations represented by formula (3) include those shown below, but are not limited to these.

[0231]

[0232] Examples of onium salts represented by formula (1) or (2) include any combination of the anions and cations exemplified above. These onium salts can be easily prepared by ion exchange reactions using known organic chemical methods. For ion exchange reactions, for example, JP-A 2007-145797 can be referenced.

[0233] The onium salt represented by formula (1) or (2) acts as a quencher in a chemically amplified resist composition, which is due to the fact that each counter-anion of the onium salt is a conjugate base of a weak acid. The weak acid used here means an acidity that is not capable of deprotecting the acid unstable group of the acid unstable group-containing unit used in the base polymer. The onium salt represented by formula (1) or (2) functions as a quencher when used in combination with an onium salt-type PAG having a conjugate base of a strong acid (typically a sulfonic acid with the α position fluorinated) as a counter-anion. In a system utilizing a mixture of an onium salt that generates a strong acid (e.g., a sulfonic acid with the α position fluorinated) and an onium salt that generates a weak acid (e.g., an unfluorinated sulfonic acid or carboxylic acid), when a strong acid generated from a PAG collides with an onium salt containing an unreacted weak acid anion upon high-energy ray irradiation, salt exchange occurs to release the weak acid, thereby forming an onium salt containing a strong acid anion. In this process, since the strong acid is exchanged for a weak acid with low catalytic activity, the acid is seemingly deactivated, allowing for the control of acid diffusion.

[0234] JP 6848776 discloses an onium salt having a sulfonium cation and a phenoxide anion site within the same molecule, JP 6583136 and JP-A 2020-200311 disclose an onium salt having a sulfonium cation and a carboxylate anion site within the same molecule, and JP 6274755 discloses an onium salt having an iodonium cation and a carboxylate anion site within the same molecule. These onium salts can also be used as quenchers (C).

[0235] In the case where the photogenerative agent that generates a strong acid is an onium salt, the strong acid generated during high-energy irradiation can be exchanged with the weak acid, but it is difficult for the weak acid generated during high-energy irradiation to collide with the unreacted strong acid-generating onium salt to induce salt exchange. This is due to the fact that onium cations are more likely to form ion pairs with the anions of strong acids.

[0236] When the chemical amplification resist composition of the present invention includes an onium salt of formula (1) or (2) as a quencher (C), the amount of onium salt used is preferably 0.1 to 20 parts by weight and more preferably 0.1 to 10 parts by weight per 80 parts by weight of base polymer (A). If the amount of component (C) is within the above range, the resolution is good and the sensitivity does not decrease significantly. The onium salt represented by formula (1) or (2) may be used alone or in combination.

[0237] The chemical amplification resist composition of the present invention may include a nitrogen-containing compound as a quencher (C). Examples of nitrogen-containing compounds (C) include primary, secondary, and tertiary amine compounds described in JP-A 2008-111103, paragraphs

[0146] to

[0164] (USP 7,537,880), specifically amine compounds having a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonic acid ester bond, and compounds in which a primary or secondary amine described in JP 3790649 is protected by a carbamate group.

[0238] As a nitrogen-containing compound, a sulfonium sulfonic acid salt having a nitrogen-containing substituent may also be used. Since such a compound functions as a quencher in the unexposed area and loses its quenching ability in the exposed area through neutralization with its own generated acid, it functions as a so-called photodisintegrating base in the exposed area. By using a photodisintegrating base, the contrast between the exposed area and the unexposed area can be further enhanced. Regarding photodisintegrating bases, for example, JP-A 2009-109595, JP-A 2012-46501, etc. may be referenced.

[0239] When the chemical amplification resist composition of the present invention includes a nitrogen-containing compound as a quencher (C), the amount of nitrogen-containing compound used is preferably 0.001 to 12 parts by weight and more preferably 0.01 to 8 parts by weight per 80 parts by weight of base polymer (A). The nitrogen-containing compound may be used alone or in combination.

[0240] (D) Acid-generating agent

[0241] The chemical amplification resist composition of the present invention may include an acid-generating agent as long as it does not impair the effects of the present invention. Typically, the acid-generating agent may be a compound that generates acid in response to active light or radiation (photo-acid generating agent). The photo-generating agent used at this time is not particularly limited as long as it generates acid upon irradiation with high-energy rays, but compounds that generate sulfonic acid, imidic acid, or methic acid are preferred. Suitable PAGs include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonic acid type acid-generating agents, etc. Examples of acid-generating agents include those described in paragraphs

[0122] to

[0142] of JP-A 2008-111103.

[0242] In addition, as other photocatalytic agents, sulfonium salts represented by the following formula (4-1) and iodonium salts represented by the following formula (4-2) are also appropriately used.

[0243]

[0244] In equations (4-1) and (4-2), R 101 ~R 105 C1-C that may each independently contain heteroatoms 20 It is a hydrocarbyl group. As the above hydrocarbyl group, the hydrocarbyl group R in formulas (a1) and (a2) is 1 ~R 5Examples such as those exemplified above may be given. Part or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and part of the -CH2- constituting the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, the hydrocarbyl group may include a hydroxyl 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 sulfone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. R 101 and R 102 They may combine together to form a ring with the sulfur atom to which they are bonded. The ring formed in this case is R in formula (a1). 1 and R 2 Examples of rings formed by combining together with the sulfur atoms to which they combine, such as those exemplified above, can be cited.

[0245] As for the cation of the sulfonium salt represented by Equation (4-1), examples include the cation of the sulfonium salt represented by Equation (a1) as exemplified above. As for the cation of the iodonium salt represented by Equation (4-2), examples include the cation of the iodonium salt represented by Equation (a2) as exemplified above.

[0246] Among equations (4-1) and (4-2), Xa - is an anion of the following formulas (4A), (4B), (4C) or (4D).

[0247]

[0248] In Equation (4A), R fa C1-C may contain fluorine atoms or heteroatoms. 40It is a hydrocarbyl group. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. An example is the hydrocarbyl group R of formula (4A') described later. 111 Examples of such things can be cited.

[0249] As an anion of formula (4A), a structure represented by the following formula (4A') is preferred.

[0250]

[0251] In equation (4A'), R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group.

[0252] In equation (4A'), R fa1 C1-C that may contain heteroatoms 38 It is a hydrocarbyl group. Suitable heteroatoms include oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc., and oxygen atoms are preferred. As for the hydrocarbyl group, it is preferable that it has 6 to 30 carbon atoms from the perspective of obtaining high resolution in fine pattern formation.

[0253] C1-C 38 Hydrocarbilgi R fa1 It may be saturated or unsaturated, and may be linear, branched, or cyclic. Examples include C1-C groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and icosyl. 38 Alkyl groups; C3-C groups such as cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, 1-adamantylmethyl group, norbornyl group, norbornylmethyl group, tricyclodecyl group, tetracyclododecyl group, tetracyclododecylmethyl group, dicyclohexylmethyl group, etc. 38 C2-C of cyclic saturated hydrocarbyl group; allyl group, 3-cyclohexenyl group, etc.38 unsaturated aliphatic hydrocarbyl groups; C6-C groups such as phenyl groups, 1-naphthyl groups, 2-naphthyl groups, etc. 38 Aryl groups; C7-C groups such as benzyl groups, diphenylmethyl groups, etc. 38 Examples include Aralkilgi; combinations of these.

[0254] Some or all of the hydrogen atoms of the above hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- constituting the above hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, the above hydrocarbyl group may include a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sulfone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. As the above heteroatom, an oxygen atom is preferred. Examples of hydrocarbyl groups containing heteroatoms include tetrahydrofuryl groups, methoxymethyl groups, ethoxymethyl groups, methylthiomethyl groups, acetamidomethyl groups, trifluoroethyl groups, (2-methoxyethoxy)methyl groups, acetoxymethyl groups, 2-carboxy-1-cyclohexyl groups, 2-oxopropyl groups, 4-oxo-1-adamantyl groups, 3-oxocyclohexyl groups, etc.

[0255] For the synthesis of sulfonium salts containing anions of formula (4A'), refer to JP-A 2007-145797, JP-A 2008-106045, JP-A 2009-7327, JP-A 2009-258695, etc. Additionally, sulfonium salts described in JP-A 2010-215608, JP-A 2012-41320, JP-A 2012-106986, JP-A 2012-153644, etc. are also useful.

[0256] Examples of anions represented by formula (4A) include those shown below, but are not limited to these. In the following formulas, Ac is an acetyl group.

[0257]

[0258]

[0259] In Equation (4B), R fb1 and R fb2 C1-C atoms may each independently contain a fluorine atom or a heteroatom. 40 It is a hydrocarbyl group. The above hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. An example of a hydrocarbyl group is the hydrocarbyl group R in formula (4A'). fa1 As such, examples such as those exemplified above can be cited. R fb1 and R fb2 Each is preferably a fluorine atom or a straight-chain C1-C4 fluorinated alkyl group. R fb1 and R fb2 The pairs combine together, and the groups to which they combine (-CF2-SO2-N - It may form a ring together with -SO2-CF2-), and the ring-forming pair is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0260] In Equation (4C), R fc1 , R fc2 and R fc3 C1-C that may each independently contain a fluorine atom or a heteroatom 40 It is a hydrocarbyl group. The above hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. An example of a hydrocarbyl group is the hydrocarbyl group R in formula (4A'). fa1 As such, examples such as those exemplified above can be cited. R fc1 , R fc2 and R fc3Each is preferably a fluorine atom or a straight-chain C1-C4 fluorinated alkyl group. fc1 and R fc2 The pairs combine together, and the groups to which they combine (-CF2-SO2-C - It may form a ring together with -SO2-CF2-), and the ring-forming pair is preferably a fluorinated ethylene group or a fluorinated propylene group.

[0261] In equation (4D), R fd C1-C that may contain heteroatoms 40 It is a hydrocarbyl group. The above hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. An example of a hydrocarbyl group is the hydrocarbyl group R in formula (4A'). fa1 Examples such as those exemplified above can be cited.

[0262] For the synthesis of sulfonium salts containing the anion of formula (4D), refer to JP-A 2010-215608 and JP-A 2014-133723.

[0263] Examples of anions represented by formula (4D) include those shown below, but are not limited to these.

[0264]

[0265] The photogenerator containing an anion represented by formula (4D) does not have a fluorine atom at the α position of the sulfon group, but has two trifluoromethyl groups at the β position. Due to this, it has sufficient acidity to cleave acid unstable groups in the base polymer. Therefore, the compound is an effective photogenerator.

[0266] As a photogenerator, a compound represented by the following formula (5) can also be appropriately used.

[0267]

[0268] In Equation (5), R 201 and R 202C1-C that may each independently contain heteroatoms 30 It is hydrocarbyl. R 203 C1-C that may contain heteroatoms 30 It is a hydrocarbylene group. R 201 and R 202 and R 203 Any two of them may combine together to form a ring with the sulfur atom to which they are bonded. As the ring, R in formula (a1) 1 and R 2 Examples of rings formed by combining together with the sulfur atoms to which they combine, such as those exemplified above, can be cited.

[0269] C1-C 30 Hydrocarbilgi R 201 and R 202 It may be saturated or unsaturated, and may be linear, branched, or cyclic. Examples include C1-C groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl groups. 30 Alkyl group; cyclopentyl group, cyclohexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylbutyl group, norbornyl group, oxanorbornyl group, tricyclo[5.2.1.0 2,6 C3-C groups such as decyl and adamantyl groups 30 Cyclic saturated hydrocarbyl group; C6-C groups 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, anthracenyl group, etc. 30Examples include aryl groups; combinations thereof. Some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, or halogen atoms, and some of the -CH2- constituting the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen atoms, sulfur atoms, or nitrogen atoms. As a result, the hydroxycarbyl group may include a hydroxyl 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 sulfonic acid ester bond, a carbonate bond, a lactone ring, a sulfone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0270] C1-C 30 Hydrocarbylen group R 203 It may be saturated or unsaturated, and may be linear, branched, or cyclic. Examples include C1-C groups such as methane diyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl, and heptadecane-1,17-diyl. 30 Alkanedyl group; C3-C groups such as cyclopentanediyl group, cyclohexanedyl group, norbornandyl group, adamantandyl group, etc. 30Cyclic saturated hydrocarbylene group; C6-C groups such as phenylene, methylphenylene, ethylphenylene, n-propylphenylene, isopropylphenylene, n-butylphenylene, isobutylphenylene, sec-butylphenylene, tert-butylphenylene, naphthylene, methylnaphthylene, ethylnaphthylene, n-propylnaphthylene, isopropylnaphthylene, n-butylnaphthylene, isobutylnaphthylene, sec-butylnaphthylene, tert-butylnaphthylene, etc. 30 Examples include arylene groups; combinations thereof. Some or all of the hydrogen atoms of the hydrocarbylene group may be substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, and some of the -CH2- constituting the hydrocarbylene group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms. As a result, the hydroxycarbylene group may include a hydroxyl 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 sulfonic acid ester bond, a carbonate bond, a lactone ring, a sulfone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. As the heteroatom, an oxygen atom is preferred.

[0271] In formula (5), L A is a linear, branched, or cyclic C1-C bond that may contain single bonds, ether bonds, or heteroatoms. 20 It is a hydrocarbylene group. The above hydrocarbylene group may be saturated or unsaturated, and may be linear, branched, or cyclic. An example of a hydrocarbylene group is the hydrocarbylene group R 203 Examples such as those exemplified above can be cited.

[0272] In equation (5), X A , X B , X C and X DEach is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. However, X A , X B , X C and X D At least one of them is a fluorine atom or a trifluoromethyl group.

[0273] In equation (5), k is an integer from 0 to 3.

[0274] As for the photogenerative agent represented by formula (5), it is preferable to have it represented by the following formula (5').

[0275]

[0276] In equation (5'), L A is as defined above. R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R 301 , R 302 and R 303 C1-C that may each independently contain heteroatoms 20 It is a hydrocarbyl group. The above hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. An example of a hydrocarbyl group is the hydrocarbyl group R in formula (4A'). fa1 Examples such as those exemplified above can be given. x and y are each independently integers from 0 to 5. z is an integer from 0 to 4.

[0277] As a photocatalytic agent represented by Equation (5), examples include the photocatalytic agent represented by Equation (2) of JP-A 2017-26980.

[0278] Among the above photocatalytic agents, those containing anion of formula (4A') or (4D) are particularly desirable because they have low acid diffusion and excellent solubility in resist solvents. Additionally, those represented by formula (5') are particularly desirable because they have very low acid diffusion.

[0279] As other acid-generating agents, sulfonium salts and iodonium salts represented by the following formulas (6-1) or (6-2) may be used. These salts contain anions having an aromatic ring substituted with an iodine atom.

[0280]

[0281] In equations (6-1) and (6-2), p is an integer from 1 to 3. q is an integer from 1 to 5, r is an integer from 1 to 3, and the sum of q+r is an integer from 1 to 5. It is preferable that q be an integer from 1 to 3, and more preferably 2 or 3. r is an integer from 0 to 2.

[0282] Among equations (6-1) and (6-2), L 1 It is a C1-C6 saturated hydrocarbylene group that may include a single bond, an ether bond or an ester bond, or an ether bond or an ester bond. The saturated hydrocarbylene group may be straight, branched, or cyclic.

[0283] Among equations (6-1) and (6-2), L 2 is, when p=1, a single bond or C1-C 20 It is a divalent linker, and when p=2 or 3, C1-C 20 The (p+1) of the linker is a linker, and the linker may include an oxygen atom, a sulfur atom, or a nitrogen atom.

[0284] In equations (6-1) and (6-2), R 401 C1-C that may include a hydroxyl group, a carboxyl group, a fluorine atom, a chlorine atom, a bromine atom, or an amino group, or a fluorine atom, a chlorine atom, an iodine atom, a hydroxyl group, an amino group, or an ether bond. 20 Hydrocarbyl group, C1-C 20 Hydrocarbyloxygen, C2-C 20 Hydrocarbylcarbonyl group, C2-C 20 Hydrocarbyloxycarbonyl group, C2-C 20 Hydrocarbylcarbonyloxygen or C1-C20 Hydrocarbylsulfonyloxy group, or -N(R 401A )(R 401B ), -N(R 401C )-C(=O)-R 401D or -N(R 401C )-C(=O)-OR 401D is. R 401A and R 401B is independently a hydrogen atom or a C1-C6 saturated hydrocarbyl group. R 401C is a hydrogen atom or a C1-C6 saturated hydrocarbyl group, and may include a halogen atom, a hydroxyl group, a C1-C6 saturated hydrocarbyloxy group, a C2-C6 saturated hydrocarbylcarbonyl group, or a C2-C6 saturated hydrocarbylcarbonyloxy group. 401D is C1-C 16 aliphatic hydrocarbilic group, C6-C 14 aryl group or C7-C 15 It is an aralkyl group, a halogen atom, a hydroxyl group, a C1-C6 saturated hydrocarbyloxy group, a C2-C6 saturated hydrocarbylcarbonyl group, or a C2-C6 saturated hydrocarbylcarbonyloxy group. The aliphatic hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. The hydrocarbyl group, hydrocarbyloxy group, hydrocarbylcarbonyl group, hydrocarbyloxycarbonyl group, hydrocarbylcarbonyloxy group, and hydrocarbylsulfonyloxy group may be linear, branched, or cyclic. When p and / or r are 2 or more, group R 401 It may be the same or different.

[0285] Among these, R 401 As, hydroxyl group, -N(R 401C )-C(=O)-R 401D , -N(R 401C )-C(=O)-OR 401D Fluorine atoms, chlorine atoms, bromine atoms, methyl groups, methoxy groups, etc. are preferred.

[0286] Among equations (6-1) and (6-2), Rf 11~Rf 14 Each is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, and Rf 11 ~Rf 14 At least one of them is a fluorine atom or a trifluoromethyl group. Rf 11 and Rf 12 It may be combined to form a carbonyl group. Preferably, Rf 13 and Rf 14 It is desirable that all of them are fluorine atoms.

[0287] In equations (6-1) and (6-2), R 402 ~R 406 C1-C atoms may each independently contain halogen atoms or heteroatoms. 20 It is a hydrocarbyl group. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. An example thereof is the hydrocarbyl group R in formulas (a1) and (a2). 1 ~R 5 Examples such as those exemplified above may be given. Part or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, a nitro group, a mercapto group, a sulfone ring, a sulfo group, or a sulfonium salt-containing group, and part of the -CH2- constituting the hydrocarbyl group may be substituted with an ether bond, an ester bond, a carbonyl group, an amide bond, a carbonate bond, or a sulfonic acid ester bond. R 402 and R 403 These may combine together to form a ring with the sulfur atom to which they are bonded. As the ring, R in formula (a1) 1 and R 2 Examples of rings formed by combining together with the sulfur atoms to which they combine, such as those exemplified above, can be cited.

[0288] As for the cation of the sulfonium salt represented by Formula (6-1), examples include the cation of the sulfonium salt represented by Formula (a1) as exemplified above. As for the cation of the iodonium salt represented by Formula (6-2), examples include the cation of the iodonium salt represented by Formula (a2) as exemplified above.

[0289] Examples of anions of onium salts represented by formula (6-1) or (6-2) include those shown below, but are not limited to these.

[0290]

[0291]

[0292]

[0293]

[0294]

[0295]

[0296]

[0297]

[0298]

[0299]

[0300]

[0301]

[0302]

[0303]

[0304]

[0305]

[0306]

[0307]

[0308]

[0309]

[0310]

[0311]

[0312] When the chemical amplification resist composition of the present invention includes an acid generator (D), the amount of acid generator (D) used is preferably 0.1 to 40 parts by weight and more preferably 0.5 to 20 parts by weight per 80 parts by weight of base polymer (A). If the amount of acid generator (D) is within the above range, good resolution is ensured, and there is no risk of foreign matter issues occurring after development or peeling of the resist film. The acid generator (D) may be used alone or in combination.

[0313] (E) Surfactant

[0314] The chemical amplification resist composition of the present invention may further include a surfactant (E). Typically, (E) is a surfactant that is insoluble or sparingly soluble in water and an alkaline developer, or a surfactant that is insoluble or sparingly soluble in water and soluble in an alkaline developer. As surfactants, the compounds described in JP-A 2010-215608 and JP-A 2011-16746 may be referenced.

[0315] Numerous examples of surfactants that are insoluble or sparingly soluble in water and alkaline developers are described in the patent literature cited herein, examples of which preferred are the fluorochemical surfactants FC-4430 (3M), Olfine®R E1004 (Nissin Chemical Co., Ltd.), Surflon®R S-381, KH-20, and KH-30 (AGC Seimi Chemical Co., Ltd.). Partially fluorinated oxetane ring-opening polymers represented by the following formula (surf-1) are also useful.

[0316]

[0317] Here, R, Rf, A, B, C, m, and n apply only to Formula (surf-1), regardless of the aforementioned description of the surfactant. R is a 2- to 4-valent C2-C5 aliphatic group. Examples of the aliphatic groups include, for divalent groups, ethylene groups, 1,4-butylene groups, 1,2-propylene groups, 2,2-dimethyl-1,3-propylene groups, 1,5-pentylene groups, etc. Examples of trivalent and tetravalent groups include the following.

[0318]

[0319] In the formulas, the dashed lines represent valence bonds. These formulas are substructures derived from glycerol, trimethylolethane, trimethylolpropane, pentaerythritol, etc.

[0320] Among these, 1,4-butylene groups, 2,2-dimethyl-1,3-propylene groups, etc. are preferred.

[0321] Rf is a trifluoromethyl group or a pentafluoroethyl group, preferably a trifluoromethyl group. The subscript m is an integer from 0 to 3, n is an integer from 1 to 4, the sum of n and m is the valence of R, and is an integer from 2 to 4. "A" is 1, B is an integer from 2 to 25, and C is an integer from 0 to 10. B is preferably an integer from 4 to 20, and C is preferably 0 or 1. Furthermore, the arrangement of each constituent unit in formula (surf-1) is not specified, and may be arranged in blocks or randomly. For the preparation of surfactants in the form of partially fluorinated oxetane ring-opening polymers, refer, for example, to USP 5,650,483.

[0322] A surfactant that is insoluble or sparingly soluble in water and soluble in an alkaline developer is useful when applying ArF immersion lithography to a resist composition without using a resist protective film. In this embodiment, the surfactant tends to achieve the function of reducing water penetration or leaching by orienting on the surface of the resist film. The surfactant is also effective in reducing damage to the exposure device by suppressing the leaching of water-soluble components from the resist film. The surfactant becomes solubilized during alkaline aqueous development after exposure and PEB, making it difficult to form foreign substances that cause defects. As such a surfactant, a polymeric surfactant that is insoluble or sparingly soluble in water and soluble in an alkaline developer, also referred to as a "hydrophobic resin" in this sense, is particularly desirable to have high water repellency and improved water activity.

[0323] As such a polymeric surfactant, it is suitable to include at least one repeating unit selected from the following formulas (7A) to (7E).

[0324]

[0325] Among equations (7A) to (7E), R B is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. W 1 It is -CH2-, -CH2CH2-, or -O-, or two separate -Hs. R s1 Each is independently a hydrogen atom or C1-C 10 It is hydrocarbyl. R s2 is a single bond, or a C1-C5 straight-chain or branched hydrocarbylene group. R s3 Each independently consists of hydrogen atoms, C1-C 15 It is a hydrocarbyl group, a fluorinated hydrocarbyl group, or an acid-unstable group. R s3 In the case of this hydrocarbyl group or fluorinated hydrocarbyl group, an ether bond or a carbonyl group may be interposed between the carbon-carbon bonds. R s4 is C1-C20 It is a hydrocarbon group or fluorinated hydrocarbon group of the (u+1) valence. u is an integer from 1 to 3. R s5 Each independently consists of a hydrogen atom, or a group -C(=O)-OR sa and, among the formulas, R sa is C1-C 20 It is the fluorinated hydrocarbyl group of. R s6 C1-C 15 It is a hydrocarbyl group or a fluorinated hydrocarbyl group, and an ether bond or a carbonyl group may be interposed between the carbon-carbon bonds.

[0326] C1-C 10 Hydrocarbilgi R s1 As such, a saturated hydrocarbyl group is preferred and may be straight, branched, or cyclic. Examples include C1-C groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups. 10 C3-C groups such as alkyl groups, cyclopropyl groups, cyclobutyl groups, cyclopentyl groups, cyclohexyl groups, adamantyl groups, norbornyl groups 10 Examples include cyclic saturated hydrocarbyl groups. Among these, C1-C6 groups are preferred.

[0327] Hydrocarbylen group R s2 As such, a saturated hydrocarbylene group is preferred, and may be straight, branched, or cyclic. Examples include methylene groups, ethylene groups, propylene groups, butylene groups, pentylene groups, etc.

[0328] Hydrocarbilgi R s3 or R s6 It may be saturated or unsaturated, and may be linear, branched, or cyclic. Examples include aliphatic unsaturated hydrocarbyl groups such as saturated hydrocarbyl groups, alkenyl groups, and alkynyl groups, but saturated hydrocarbyl groups are preferred. As the above saturated hydrocarbyl group, hydrocarbyl group Rs1 In addition to those exemplified as such, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, etc. are suitable. Fluorinated hydrocarbyl group R s3 or R s6 Examples include groups in which some or all of the hydrogen atoms bonded to the carbon atoms of the aforementioned hydrocarbyl group are substituted with fluorine atoms. In these groups, as previously mentioned, an ether bond or a carbonyl group may be interposed between these carbon-carbon bonds.

[0329] Forest fire stabilization period R s3 As such, the groups of the above formulas (AL-3) to (AL-5), trialkylsilyl groups in which each alkyl group is a C1-C6 alkyl group, and C4-C 20 Examples include oxoalkyl groups.

[0330] (u+1) valence hydrocarbon group or fluorinated hydrocarbon group R s4 It may be a straight chain, branched, or cyclic group, and examples thereof include a group from which "u" hydrogen atoms have been removed from the aforementioned hydrocarbyl group or fluorinated hydrocarbyl group.

[0331] Fluorinated hydrocarbyl group R sa It is preferable that it be saturated, and it may be linear, branched, or cyclic. An example is that some or all of the hydrogen atoms of the hydrocarbyl group are substituted with fluorine atoms. Specific examples include trifluoromethyl groups, 2,2,2-trifluoroethyl groups, 3,3,3-trifluoro-1-propyl groups, 3,3,3-trifluoro-2-propyl groups, 2,2,3,3-tetrafluoropropyl groups, 1,1,1,3,3,3-hexafluoroisopropyl groups, 2,2,3,3,4,4,4-heptafluorobutyl groups, 2,2,3,3,4,4,5,5-octafluoropentyl groups, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl groups, 2-(perfluorobutyl)ethyl groups, 2-(perfluorohexyl)ethyl groups, 2-(perfluorooctyl)ethyl groups, 2-(perfluorodecyl)ethyl groups, etc.

[0332] Examples of repeating units for equations (7A) to (7E) include those shown below, but are not limited thereto. In the equations, R B is as defined above.

[0333]

[0334]

[0335]

[0336] The above polymeric surfactant may further include repeating units other than those represented by formulas (7A) to (7E). Typical examples of other repeating units are those obtained from methacrylic acid and α-trifluoromethylacrylic acid derivatives. Among the polymeric surfactants, the content of the repeating units represented by formulas (7A) to (7E) is preferably 20 mol% or more of the total repeating units, more preferably 60 mol% or more, and most preferably 100 mol%.

[0337] The Mw of the above polymeric surfactant is preferably 1,000 to 500,000, more preferably 3,000 to 100,000, and the Mw / Mn is preferably 1.0 to 2.0, more preferably 1.0 to 1.6.

[0338] The above polymeric surfactant can be synthesized by dissolving monomer(s) containing repeating units represented by formulas (7A) to (7E) and, if necessary, other repeating units, into an organic solvent, adding a radical initiator, heating, and polymerizing. Suitable organic solvents for this purpose include toluene, benzene, THF, diethyl ether, and dioxane. Suitable polymerization initiators for this purpose include AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The reaction temperature is preferably 50 to 100°C, and the reaction time is preferably 4 to 24 hours. The acid instability group may be used as is, introduced into the monomer, or may be protected or partially protected after polymerization.

[0339] When synthesizing the above polymeric surfactant, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol may be used to adjust the molecular weight. An appropriate amount of chain transfer agent is 0.01 to 10 mol% with respect to the total moles of monomers to be polymerized.

[0340] When the chemically amplified resist composition includes a surfactant (E), the amount of surfactant (E) used is 0.1 to 50 parts by weight per 80 parts by weight of base polymer (A), and 0.5 to 10 parts by weight is more preferable. If the amount of surfactant (E) is 0.1 parts by weight or more, the receding contact angle between the surface of the resist film and water is sufficiently improved. If the amount of surfactant (E) is 50 parts by weight or less, the dissolution rate of the surface of the resist film with respect to the developer is low, so the height of the formed fine-sized pattern is sufficiently maintained. The surfactant (E) may be used alone or in combination.

[0341] (F) Dissolution inhibitor

[0342] The chemical amplification resist composition of the present invention may further include a dissolution inhibitor (F). When the chemical amplification resist composition of the present invention is of the positive type, by incorporating a dissolution inhibitor, the difference in dissolution rates between the exposed and unexposed parts can be further increased, thereby further improving the resolution.

[0343] Examples of dissolution inhibitors that can be used at this time include compounds having a molecular weight preferably 100 to 1,000, more preferably 150 to 800, in which the hydrogen atoms of the phenolic hydroxyl groups of a compound containing two or more phenolic hydroxyl groups on the molecule are substituted with acid unstable groups at an average of 0 to 100 mol% as a whole, or compounds having one or more carboxyl groups of a compound in which the hydrogen atoms of the carboxyl groups are substituted with acid unstable groups at an average of 50 to 100 mol% as a whole. Typically, examples include derivatives in which the hydrogen atoms of the hydroxyl or carboxyl groups of bisphenol A, trisphenol, phenolphthalein, cresol novolac, naphthalenecarboxylic acid, adamantancarboxylic acid, and cholic acid are substituted with acid unstable groups, as described in paragraphs

[0155] to

[0178] of JP-A 2008-122932.

[0344] When the chemical amplification resist composition of the present invention includes a dissolution inhibitor (F), the amount of dissolution inhibitor (F) used is preferably 0 to 50 parts by weight and more preferably 5 to 40 parts by weight with respect to 80 parts by weight of base polymer (A).

[0345] (G) Other ingredients

[0346] The chemical amplification resist composition of the present invention may further include (G) other components, such as a compound that decomposes by an acid to generate another acid (i.e., an acid-multiplying compound), an organic acid derivative, a fluorinated alcohol, a water-repellent enhancer, etc. The acid-multiplying compound is described in JP-A 2009-269953 and JP-A 2010-215608. The amount of the acid-multiplying compound used is preferably 0 to 5 parts by weight and more preferably 0 to 3 parts by weight per 80 parts by weight of the base polymer (A). If the amount of the acid-multiplying compound is excessively large, it becomes difficult to control acid diffusion, which may result in deterioration of resolution and deterioration of pattern shape. Regarding the organic acid derivative and the fluorinated alcohol, reference may be made to JP-A 2009-269953 and JP-A 2010-215608.

[0347] The above-mentioned water repellency enhancer can be used in immersion lithography without a topcoat. Suitable water repellency enhancers include polymers containing fluorinated alkyl groups and polymers containing 1,1,1,3,3,3-hexafluoro-2-propanol residues of a specific structure, as described, for example, in JP-A 2007-297590, JP-A 2008-111103, etc. The water repellency enhancer added to the above-mentioned resist composition must be soluble in alkaline developers and organic solvent developers. Water repellency enhancers having 1,1,1,3,3,3-hexafluoro-2-propanol residues of a specific structure have good solubility in developers. Polymers containing amino groups or amine salts copolymerized as repeating units are highly effective in preventing the evaporation of acid in the PEB, thereby preventing defects in the opening of the hole pattern after development. When the chemical amplification resist composition of the present invention includes the water repellency enhancer, the amount of water repellency enhancer used is preferably 0 to 20 parts by weight and more preferably 0.5 to 10 parts by weight with respect to 80 parts by weight of base polymer (A).

[0348] Pattern formation method

[0349] The chemical amplification resist composition of the present invention is used in the manufacture of various integrated circuits. Pattern formation using the chemical amplification resist composition can be performed by known lithography techniques. A pattern formation method generally comprises the steps of applying the chemical amplification resist composition onto a substrate to form a resist film, exposing the resist film to high-energy rays, and developing the exposed resist film in a developer.

[0350] First, the chemical amplification resist composition of the present invention is applied to a substrate for manufacturing an integrated circuit (e.g., Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.) or a substrate for manufacturing a mask circuit (e.g., Cr, CrO, CrON, MoSi2, SiO2, etc.) by a suitable application method such as spin coating, roll coating, flow coating, dip coating, spray coating, or doctor coating. The coating is pre-baked on a hot plate at a temperature of 60 to 150°C for 10 seconds to 30 minutes, preferably at 80 to 120°C for 30 seconds to 20 minutes. The resulting resist film generally has a thickness of 0.01 to 2.0 μm.

[0351] Next, the above-mentioned resist film is exposed to a desired pattern of high-energy rays, such as UV, far-ultraviolet rays, EB, EUV with a wavelength of 3 to 15 nm, i-rays, X-rays, soft X-rays, excimer laser light, gamma rays, synchrotron radiation, etc. When UV, far-ultraviolet rays, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, synchrotron radiation, etc. are used as the high-energy rays, the resist film is irradiated directly or using a mask having the desired pattern so that the exposure amount is preferably about 1 to 200 mJ / ㎠, more preferably about 10 to 100 mJ / ㎠. When EB is used as the high-energy rays, the resist film is irradiated directly or using a mask having the desired pattern so that the exposure amount is preferably about 0.1 to 100 μC / ㎠, more preferably about 0.5 to 50 μC / ㎠. The chemical amplification resist composition of the present invention is suitable for fine patterning using high-energy rays such as ArF excimer laser light with a wavelength of 193 nm, KrF excimer laser light with a wavelength of 248 nm, EB, EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, γ-rays, or synchrotron radiation.

[0352] After exposure, the resist film may be baked (PEB) on a hot plate, preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 60 to 120°C for 30 seconds to 20 minutes.

[0353] After exposure or after PEB, the resist film is developed in a developer in the form of an aqueous basic solution for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by conventional methods such as immersion, puddle, or spray. A typical developer is an aqueous solution of 0.1 to 10 weight%, preferably 2 to 5 weight%, tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc. The resist film in the exposed portion is dissolved in the developer, while the resist film in the unexposed portion is not dissolved. In this way, a desired positive pattern is formed on the substrate.

[0354] In the formation of a negative pattern, an organic solvent developer may be used instead of a basic aqueous solution. The developer used at this time is 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutylketone, 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 penthenate, methyl crotonicate, ethyl crotonicate, methyl propionate, ethyl propionate, 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, Examples include 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. The above organic solvents may be used alone or in combination.

[0355] At the end of the development process, the resist film may be rinsed. As for the rinsing solution, a solvent that does not dissolve the resist film when mixed with the developer is preferred. As such a solvent, C3-C 10Alcohol, C8-C 12 Ether compound, C6-C 12 Alkanes, alkenes and alkynes, aromatic solvents, etc. are suitable.

[0356] The above C3-C 10 As alcohols, 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, Examples include 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, etc.

[0357] The above C8-C 12 Examples of ether compounds 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, etc.

[0358] The above C6-C 12 Examples of alkanes include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. The above C6-C 12 Examples of alkenes include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. The above C6-C 12 Examples of alkynes include hexine, heptin, and octine.

[0359] Examples of the above aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, mesitylene, etc.

[0360] Rinsing is effective in reducing the risk of the resist pattern collapsing or defects occurring. However, rinsing is not essential. By not rinsing, the amount of solvent used can be reduced.

[0361] The hole pattern or trench pattern after development can be shrunk using Thermal Flow, RELACS® technology, or DSA technology. A shrinkage agent is applied to the hole pattern and baked; by the diffusion of an acid catalyst from the resist layer during baking, crosslinking of the shrinkage agent occurs on the resist surface, and the shrinkage agent adheres to the sidewalls of the hole pattern, thereby shrinking 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. The hole pattern is shrunk by removing the unnecessary shrinkage agent.

[0362] Examples

[0363] The present invention will be specifically described below by presenting synthesis examples, embodiments, and comparative examples, but the present invention is not limited to these embodiments. The apparatus used is as follows.

[0364] MALDI TOF-MS: S3000 manufactured by JEOL Ltd.

[0365] [1] Synthesis of onium salt-type monomers

[0366] Example 1-1

[0367] Synthesis of onium salt-type monomer (monomer a1-1)

[0368]

[0369] (1) Synthesis of intermediate In-1

[0370] Under a nitrogen atmosphere, 37.2 g of reactant SM-1, 18.0 g of potassium carbonate, and 1.50 g of sodium iodide were dissolved or suspended in 200 g of acetone in a reaction vessel, and the internal temperature of the reaction vessel was raised to 50°C. Subsequently, 16.4 g of isopropyl chloroacetate was added dropwise. After adding, the reaction mixture was heated under reflux for 6 hours. Afterward, the reaction solution was cooled, and 100 g of water was added to stop the reaction. The reaction product was extracted twice with 200 g of ethyl acetate, followed by a conventional aqueous work-up, and the solvent was distilled. Subsequently, by purification by silica gel chromatography, 45.8 g of the intermediate In-1 was obtained as an oil phase (yield 97%).

[0371] (2) Synthesis of intermediate In-2

[0372] Under a nitrogen atmosphere, 45.8 g of intermediate In-1 was dissolved in 200 g of THF. While cooling the reaction vessel in an ice bath, 15.5 g of a 25 wt% aqueous sodium hydroxide solution was added dropwise. After addition, the internal temperature of the reaction vessel was raised to 30°C, and the reaction mixture was aged for 12 hours. After aging, the reaction mixture was cooled, and 18.2 g of 20 wt% hydrochloric acid was added dropwise to stop the reaction. The reaction product was extracted twice with 200 g of ethyl acetate, subjected to normal aqueous treatment, and the solvent was distilled. Subsequently, by recrystallization with hexane, 37.5 g of intermediate In-2 was obtained as white crystals (yield 90%).

[0373] (3) Synthesis of intermediate In-3

[0374] Under a nitrogen atmosphere, 37.5 g of intermediate In-2, 34.8 g of reactant SM-2, 1.1 g of 4-dimethylaminopyridine, and 150 g of methylene chloride were placed in a reaction vessel and cooled in an ice bath. While maintaining the internal temperature of the reaction vessel at 20°C or below, 20.1 g of powdered 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride was added. After addition, the reaction mixture was heated to room temperature and aged for 12 hours. After aging, 100 g of water was added to stop the reaction, followed by conventional aqueous treatment and distillation of the solvent. Subsequently, diisopropyl ether was added to recrystallize the mixture, yielding 61.5 g of intermediate In-3 as an oil phase (yield 89%).

[0375] (4) Synthesis of onium salt type monomer a1-1

[0376] Under a nitrogen atmosphere, 61.5 g of intermediate In-3, 31.8 g of reactant SM-3, 200 g of methylene chloride, and 150 g of water were placed in a reaction vessel, and the mixture was stirred for 30 minutes. Afterward, the organic layer was aliquoted, washed with water, and then concentrated under reduced pressure. By purifying the concentrate by silica gel chromatography, 61.0 g of the title monomer a1-1 was obtained as an oil phase (yield 87%).

[0377] MALDI TOF-MS: POSITIVE M + 261(C 18 H 13 S + (Significant)

[0378] NEGATIVE M-641(C 13 H8F5I2O6S - (Significant)

[0379] Examples 1-2 to 1-7

[0380] Synthesis of monomers a1-2 to a1-5, a2-1 and a2-2

[0381] Monomers a1-2 to a1-5, a2-1, and a2-2 of the following formulas were synthesized using corresponding reactants and known organic chemical reactions.

[0382]

[0383] Comparative Examples 1-1 to 1-4

[0384] Synthesis of comparative monomers Ca-1 to Ca-4

[0385] Comparative monomers ca-1 to ca-4 of the following formulas were synthesized using corresponding reactants and known organic chemical reactions.

[0386]

[0387] [2] Synthesis of base polymer

[0388] In addition to monomers a1-1 to a1-5, a2-1 and a2-2, and comparative monomers ca-1 to ca-4, monomers of the following formulas were used in the synthesis of base polymers.

[0389]

[0390] Example 2-1

[0391] Synthesis of Polymer P-1

[0392] A monomer / initiator solution was prepared by filling a flask under a nitrogen atmosphere with 46.1 g of monomer a1-1, 41.8 g of monomer b1-1, 12.3 g of monomer c-1, 3.92 g of V-601 (manufactured by Fujifilm Wako Pure Chemical Corp.), and 127 g of MEK. 46 g of MEK was added to a separate flask under a nitrogen atmosphere and heated to 80°C while stirring. The monomer solution was added dropwise to the MEK over a period of 4 hours. After the addition was finished, stirring was continued for 2 hours while maintaining the temperature of the polymerization solution at 80°C. After cooling the polymerization solution to room temperature, it was added dropwise to 2,000 g of hexane while stirring vigorously. The precipitated solid was separated by filtration. The precipitate was washed twice with 600 g of hexane and vacuum dried at 50°C for 20 hours to obtain a white powder-type polymer P-1 (amount 98.1 g, yield 98%). The Mw of polymer P-1 was 9,700, and the Mw / Mn ratio was 1.81. Additionally, Mw was measured by polystyrene conversion using GPC with DMF as the solvent.

[0393]

[0394] Examples 2-2 to 2-20 and Comparative Examples 2-1 to 2-10

[0395] Synthesis of polymers P-2 to P-20 and comparative polymers CP-1 to CP-10

[0396] The polymers shown in Tables 1 and 2 were prepared by the same procedure as in Example 2-1, except that the type and mixing ratio of the monomers were changed.

[0397]

[0398]

[0399] [3] Preparation of a resist composition

[0400] Examples 3-1 to 3-20 and Comparative Examples 3-1 to 3-10

[0401] Chemical amplification resist compositions (R-1 to R-20 and CR-1 to CR-10) were prepared by dissolving a component selected from base polymers (P-1 to P-20), a component selected from comparative base polymers (CP-1 to CP-10), a component selected from acid generators (PAG-1 and PAG-2), and a component selected from quenchers (SQ-1 to SQ-3 and AQ-1) in a solvent containing 0.01 wt% of surfactant FC-4430 (3M) in the compositions shown in Tables 3 and 4 below, and by filtering the solution with a Teflon® filter having a pore size of 0.2 μm.

[0402]

[0403]

[0404] In Tables 3 and 4, the solvents, quenchers (SQ-1 to SQ-3, AQ-1), and acid-generating agents (PAG-1, PAG-2) are as follows.

[0405] Solvent: PGMEA (propylene glycol monomethyl ether acetate)

[0406] DAA (diacetone alcohol)

[0407] Kencher: SQ-1~SQ-3, AQ-1

[0408]

[0409] Acid-generating agents: PAG-1, PAG-2

[0410]

[0411] [4] EUV lithography test (1)

[0412] Examples 4-1 to 4-20 and Comparative Examples 4-1 to 4-10

[0413] Each chemically amplified resist composition (R-1 to R-20, CR-1 to CR-10) shown in Tables 3 and 4 was spin-coated onto a silicon substrate having a 20 nm coating of a silicon-containing spin-on hard mask SHB-A940 (Shin-Etsu Chemical Co., Ltd., silicon content 43 wt%), and pre-baked on a hot plate at 100°C for 60 seconds to form a resist film with a thickness of 50 nm. Using an ASML-manufactured EUV scanner NXE3300 (NA 0.33, σ 0.9 / 0.6, dipole illumination), the resist film was exposed to EUV through a mask having a line and space (LS) of 18 nm (wafer dimension) and a pitch of 36 nm, while varying the exposure amount to a pitch of 1 mJ / cm² and the focus to a pitch of 0.020 μm. The resist film was baked (PEB) for 60 seconds at the temperatures shown in Tables 5 and 6. Afterward, puddle development was performed in a 2.38 wt% aqueous TMAH solution for 30 seconds, rinsed with a surfactant-containing rinse solution, and spin-dried. A positive LS pattern was obtained.

[0414] The obtained LS patterns were observed using a CD-SEM (CG6300, Hitachi High-Technologies Corp.), and the sensitivity, exposure latitude (EL), LWR, depth of focus (DOF), and decay limit were evaluated according to the following methods. The results are shown in Tables 5 and 6.

[0415] [Sensitivity Evaluation]

[0416] Optimal exposure amount (E) for imparting an LS pattern with a line width of 18 nm and a pitch of 36 nm op , mJ / cm²) was measured and reported as sensitivity. The smaller this value, the higher the sensitivity.

[0417] [EL Evaluation]

[0418] The exposure amount for imparting an LS pattern with a space width of 18 nm ± 10% (i.e., 16.2 to 19.8 nm) was measured. The EL (%) was calculated from the exposure amount using the following formula.

[0419] EL(%)=(|E1-E2| / E op )×100

[0420] In the formula, E1 is the optimal exposure amount for imparting an LS pattern with a line width of 16.2 nm and a pitch of 36 nm, and

[0421] E2 is the optimal exposure amount for imparting an LS pattern with a line width of 19.8 nm and a pitch of 36 nm, and

[0422] E op is the optimal exposure amount for imparting an LS pattern with a line width of 18 nm and a pitch of 36 nm. The larger this value, the better the performance.

[0423] [LWR Evaluation]

[0424] Optimal exposure amount E op For the LS pattern obtained by investigation, the dimensions of 10 points spaced apart in the longitudinal direction of the line width were measured, and a value three times the standard deviation (σ) (3σ) was determined from therein and reported as LWR. The smaller this value, the less roughness and the more uniform the line width pattern is.

[0425] [DOF Evaluation]

[0426] As a depth of focus index, the focus range that imparts an LS pattern of dimensions 18 nm ± 10% (i.e., 16.2 to 19.8 nm) was measured. The larger this value, the wider the depth of focus.

[0427] [Assessment of Line Pattern Collapse Limits]

[0428] For an LS pattern formed by exposure at an exposure amount corresponding to the optimal focus, the dimensions of 10 points spaced apart along the length of the line width were measured. The minimum line dimension at which the line could be obtained without collapse was measured and reported as the collapse limit. The smaller this value, the better the collapse limit.

[0429]

[0430]

[0431] From the results shown in Tables 5 and 6, it was revealed that the chemical amplification resist composition of the present invention, comprising a base polymer containing an onium salt-type monomer, possesses high sensitivity and excellent EL, LWR, and DOF. It was also confirmed that the resist composition has a small decay limit value and is resistant to pattern decay even in fine pattern formation. The chemical amplification resist composition of the present invention was found to be suitable as a material for EUV lithography.

[0432] [5] EUV lithography evaluation (2)

[0433] [Examples 5-1 to 5-20, Comparative Examples 5-1 to 5-10]

[0434] Each chemically amplified resist composition (R-1 to R-20, CR-1 to CR-10) shown in Tables 3 and 4 was spin-coated onto a silicon substrate having a 20 nm coating of a silicon-containing spin-on hard mask SHB-A940 (Shin-Etsu Chemical Co., Ltd., silicon content 43 wt%), and pre-baked on a hot plate at 105°C for 60 seconds to form a resist film with a thickness of 50 nm. Using an ASML EUV scanner NXE3400 (NA 0.33, σ 0.9 / 0.6, quadruple illumination), the resist film was exposed to EUV through a mask having a hole pattern with a pitch (wafer dimension) of 46 nm + 20% bias. The resist film was baked (PEB) on a hot plate at the temperatures listed in Tables 7 and 8 for 60 seconds, and developed in a 2.38 wt% TMAH aqueous solution for 30 seconds to form a hole pattern with dimensions of 23 nm.

[0435] Using a CD-SEM (CG6300) manufactured by Hitachi High-Technologies Corp., the exposure amount at which the hole pattern dimensions are formed to 23 nm was measured and reported as the sensitivity. The dimensions of 50 holes were measured, and from the results, a value three times the standard deviation (σ) (3σ) was calculated and reported as the critical dimension uniformity (CDU). The results are shown in Tables 7 and 8.

[0436]

[0437]

[0438] From the results shown in Tables 7 and 8, it was confirmed that the chemical amplification resist composition of the present invention has high sensitivity and excellent CDU.

[0439] [6] Dry etching resistance evaluation

[0440] Examples 6-1 to 6-20 and Comparative Examples 6-1 to 6-10

[0441] 2 g of each polymer shown in Tables 1 and 2 (polymers P-1 to P-20 and comparative polymers CP-1 to CP-10) was dissolved in 10 g of cyclohexanone. This solution was filtered through a filter with a pore size of 0.2 μm and spin-coated onto a Si substrate to form a film with a thickness of 300 nm, and the film was tested under the following conditions.

[0442] Etching test with CHF3 / CF4 gas:

[0443] The difference in polymer film thickness before and after etching was determined using the dry etching apparatus TE-8500P manufactured by Tokyo Electron Limited.

[0444] The etching conditions are as follows.

[0445] Chamber pressure: 40 Pa

[0446] RF Power: 1,000 W

[0447] Gap: 9 mm

[0448] CHF3 gas flow rate: 30 mL / min

[0449] CF4 gas flow rate: 30 mL / min

[0450] Ar gas flow rate: 100 mL / min

[0451] Time: 60 sec

[0452] In this evaluation, a small difference in film thickness, that is, a small amount of reduction, indicates high etching resistance.

[0453] The results of the dry etching resistance evaluation are shown in Tables 9 and 10.

[0454]

[0455]

[0456] From the results shown in Tables 9 and 10, it was confirmed that the polymer of the present invention has excellent dry etching resistance to CHF3 / CF4-based gases.

Claims

Claim 1 Onium salt type monomer having the following formula (a1) or (a2): In the expression, n1 is 0 or 1, n2 is an integer from 1 to 6, and n3 is an integer from 0 to 4, provided that when n1 is 0, the sum of n2+n3 is 4 or less, when n1 is 1, the sum of n2+n3 is 6 or less, and n4 is an integer from 0 to 4;R A is each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; and R may each independently contain a heteroatom. 20 Hydrocarbilgi and;L A and L B are each independently an ether bond, ester bond, sulfonic acid ester bond, carbonate bond, or carbamate bond; X L C1-C that may each independently contain heteroatoms 40 hydrocarbylene group;Q 1 and Q 2 are each independently a hydrogen atom, a fluorine atom, or a C1-C6 fluorinated saturated hydrocarbyl group; Q 3 and Q 4 are each independently a fluorine atom or a C1-C6 fluorinated saturated hydrocarbyl group; R 1 ~R 5 C1-C that may each independently contain heteroatoms 30 It is hydrocarbil, and here R 1 and R 2 They may combine together to form a ring with the sulfur atoms to which they combine. Claim 2 In claim 1, the onium salt type monomer of formula (a1) has the following formula (a1-1), and the onium salt type monomer of formula (a2) has the following formula (a2-1): During the meal, R A , R, L A , L B , X L , Q 1 ~Q 4 , n2~n4 and R 1 ~R 5 is as defined above. Claim 3 In paragraph 2, the onium salt type monomer of formula (a1-1) has the following formula (a1-2), and the onium salt type monomer of formula (a2-1) has the following formula (a2-2): During the meal, R A , R, L A , L B , X L , Q 1 , Q 2 , n2~n4 and R 1 ~R 5 is as defined above. Claim 4 In paragraph 3, the onium salt type monomer of formula (a1-2) has the following formula (a1-3), and the onium salt type monomer of formula (a2-2) has the following formula (a2-3): During the meal, R A , R, X L , Q 1 , Q 2 , n2~n4 and R 1 ~R 5 is as defined above. Claim 5 A polymer comprising repeating units derived from the onium salt type monomer of claim 1. Claim 6 In claim 5, a polymer further comprising a repeating unit having the following formula (b1) or (b2): In either (b1) or (b2), R A are each independently a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; X 1 Silver single bond, phenylene group, naphthylene group, *-C(=O)-OX 11 - or *-C(=O)-NH-X 11 - and, the phenylene group or naphthylene group may include a fluorine atom, C1-C 10 It may be substituted with an alkoxy group or a halogen atom, and X 11 C1-C 10 is a saturated hydrocarbylene group, a phenylene group, or a naphthylene group, and the saturated hydrocarbylene group may include a hydroxyl group, an ether bond, an ester bond, or a lactone ring; X 2 is a single bond, *-C(=O)-O- or *-C(=O)-NH-; the asterisk (*) indicates a bonding point with a carbon atom in the main chain; AL 1 and AL 2 are each independently wildfire stable periods;R 11 C1-C may contain halogen atoms, cyano groups, and heteroatoms. 20 C1-C that may contain hydrocarbyl groups and heteroatoms 20 C2-C that may contain hydrocarbyloxy groups and heteroatoms 20 Hydrocarbylcarbonyl group, C2-C that may contain heteroatoms 20 C2-C that may contain a hydrocarbylcarbonyloxy group or a heteroatom 20 It is a hydrocarbyloxycarbonyl group; a is an integer from 0 to 4; and the acid unstable group is a group selected from the following formulas (AL-1) to (AL-3). In equations (AL-1) through (AL-3), an asterisk (*) indicates a joining point. In equation (AL-1), R L1 is C1-C 40 It is a hydrocarbyl group and may include a heteroatom, said heteroatom selected from the group consisting of oxygen atoms, sulfur atoms, nitrogen atoms, fluorine atoms and iodine atoms; b is an integer from 0 to 10; and in formula (AL-2), R L2 is C1-C 40 It is a hydrocarbyl group and may contain a heteroatom, said heteroatom is selected from the group consisting of oxygen atoms, sulfur atoms, nitrogen atoms, fluorine atoms and iodine atoms; R L3 and R L4 Each is independently a hydrogen atom or C1-C 20 It is a hydrocarbyl group and may contain a heteroatom, said heteroatom is selected from the group consisting of oxygen atoms, sulfur atoms, nitrogen atoms, fluorine atoms and iodine atoms; R L2 , R L3 and R L4 Any two of them bond together with the carbon atom they bond to, or with a carbon atom or an oxygen atom, to form a C3-C 20 It may form a ring; among formula (AL-3), R L5 , R L6 and R L7 C1-C each independently 20 It is a hydrocarbyl group and may contain a heteroatom, said heteroatom is selected from the group consisting of oxygen atoms, sulfur atoms, nitrogen atoms, fluorine atoms and iodine atoms; R L5 , R L6 and R L7 Any two of them combine together with the carbon atom they bond to, forming a C3-C bond. 20 It is also acceptable to form a ring. Claim 7 In claim 5, a polymer further comprising a repeating unit having the following formula (c1): During the meal, 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-, and the asterisk (*) indicates the bonding point with a carbon atom in the main chain;R 21 C1-C may contain halogen atoms, nitro groups, cyano groups, and heteroatoms. 20 C1-C that may contain hydrocarbyl groups and heteroatoms 20 C2-C that may contain hydrocarbyloxy groups and heteroatoms 20 Hydrocarbylcarbonyl group, C2-C that may contain heteroatoms 20 C2-C that may contain a hydrocarbylcarbonyloxy group or a heteroatom 20 It is a hydrocarbyloxycarbonyl group; c is an integer from 1 to 4, and d is an integer from 0 to 3, provided that the sum of c+d is 1 or more and 5 or less. Claim 8 In claim 5, a polymer further comprising a repeating unit having the following formula (d1): During the meal, R A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; Z 1 Silver single bond, phenylene group, naphthylene group, *-C(=O)-OZ 11 - or *-C(=O)-NH-Z 11 - and, the phenylene group or naphthylene group may include a fluorine atom, C1-C 10 It may be substituted with an alkoxy group or a halogen atom, and an asterisk (*) indicates a bonding point with a carbon atom in the main chain, and Z 11 C1-C 10 is a saturated hydrocarbylene group, a phenylene group, or a naphthylene group, and the saturated hydrocarbylene group may include a hydroxyl group, an ether bond, an ester bond, or a lactone ring; R 31 A C1-C comprising at least one structure selected from a hydrogen atom, or a hydroxyl group other than a phenolic hydroxyl group, a cyano group, a carbonyl group, a carboxyl group, an ether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sulfone ring, and a carboxylic acid anhydride (-C(=O)-OC(=O)-). 20 It is hydrocarbilgi. Claim 9 (A) A chemical amplification resist composition comprising a base polymer comprising the polymer of claim 5. Claim 10 In claim 9, (B) a chemical amplification resist composition further comprising an organic solvent. Claim 11 In claim 9, (C) a chemical amplification resist composition further comprising a quencher. Claim 12 In claim 9, (D) a chemical amplification resist composition further comprising an acid-generating agent. Claim 13 In claim 9, (E) a chemical amplification resist composition further comprising a surfactant. Claim 14 In claim 9, (F) a chemical amplification resist composition further comprising a dissolution inhibitor. Claim 15 A pattern forming method comprising the steps of: applying a chemical amplification resist composition of claim 9 onto a substrate to form a resist film; exposing the resist film to high-energy rays; and developing the exposed resist film in a developer. Claim 16 A pattern forming method according to claim 15, wherein the high-energy line is an ArF excimer laser having a wavelength of 193 nm, a KrF excimer laser having a wavelength of 248 nm, an electron beam, or an EUV having a wavelength of 3 to 15 nm. Claim 17 In paragraph 1, X L An onium salt-type monomer selected from groups represented by the following formula: In the formula, the asterisk (*) is L A and L B Indicates the connection point with.

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