Onium salt, resist composition, and patterning process

Abstract

[Problem] To provide a novel onium salt for use in a resist composition that is capable of high sensitivity and excellent resolution, improving LWR and CDU, and suppressing the breakdown of the resist pattern, whether in positive or negative type lithography. [Solution] An onium salt characterized by being represented by the following general formula (1). (In the formula, n1 is an integer of 0 or 1. n2 is an integer of 0 to 3. R1a is a hydrocarbyl group having 1 to 20 carbon atoms, which may contain a halogen atom or a heteroatom. n3 is an integer of 0 to 3. R1b is a hydrocarbyl group having 1 to 36 carbon atoms, which may contain a heteroatom. n4 is an integer of 1 or 2. Z+ represents an onium cation.)

Description

Technology Field

[0001] The present invention relates to a resist composition comprising an onium salt and an acid diffusion control agent comprising the onium salt, and a pattern forming method using the resist composition. Background Technology

[0002] With the increasing integration and speed of LSIs, the miniaturization of pattern rules is progressing rapidly. This is because the widespread adoption of 5G high-speed communication and artificial intelligence (AI) is creating a need for high-performance devices to process them. As a cutting-edge miniaturization technology, 5 nm node devices are being mass-produced using extreme ultraviolet (EUV) lithography with a wavelength of 13.5 nm. Furthermore, the use of EUV lithography is being explored for next-generation 3 nm node and next-next-generation 2 nm node devices as well.

[0003] With the progress of miniaturization, image blurring caused by acid diffusion is becoming a problem. It has been suggested that in order to secure resolution in fine patterns with a size of 45 nm or larger, control of acid diffusion is important in addition to the improvement of dissolution contrast proposed in the past (Non-patent Literature 1). However, since chemical amplification resist materials (compositions) increase sensitivity and contrast through acid diffusion, if one attempts to suppress acid diffusion to the extreme by lowering the post-exposure bake (PEB) temperature or shortening the time, sensitivity and contrast are significantly reduced.

[0004] The triangle triad-off relationship of sensitivity, resolution, and edge roughness is revealed. To improve resolution, it is necessary to suppress acid diffusion, but sensitivity decreases as the acid diffusion distance becomes shorter.

[0005] It is effective to suppress acid diffusion by adding an acid-generating agent that generates bulky acid. Therefore, it has been proposed to include repeating units derived from onium salts having polymerizable unsaturated bonds in a polymer. In this case, the polymer also functions as an acid-generating agent (polymer-bound acid-generating agent). Patent Document 1 proposes a sulfonium salt or iodonium salt having polymerizable unsaturated bonds that generates a specific sulfonic acid. Patent Document 2 proposes a sulfonium salt in which a sulfonic acid is directly linked to the main chain.

[0006] The acid instability group used in (meth)acrylate polymers for ArF resist materials undergoes a deprotection reaction when using a photogenerator that generates a sulfonic acid with the α position substituted with a fluorine atom, but the deprotection reaction does not proceed with an acidgenerator that generates a sulfonic acid or carboxylic acid with the α position not substituted with a fluorine atom. When a sulfonium salt or iodonium salt that generates a sulfonic acid with the α position substituted with a fluorine atom is mixed with a sulfonium salt or iodonium salt that generates a sulfonic acid with the α position not substituted with a fluorine atom, the sulfonium salt or iodonium salt that generates a sulfonic acid with the α position not substituted with a fluorine atom undergoes ion exchange with the sulfonic acid with the α position substituted with a fluorine atom. Sulfonic acid in which the α position is substituted with a fluorine atom by light is reversed back into a sulfonium salt or iodonium salt by ion exchange, so the sulfonium salt or iodonium salt of a sulfonic acid or carboxylic acid in which the α position is not substituted with a fluorine atom functions as a quencher (acid diffusion control agent). A resist material utilizing a sulfonium salt or iodonium salt that generates a carboxylic acid as a quencher has been proposed (Patent Document 3).

[0007] Sulfonium salt-type quenchers that generate various carboxylic acids have been proposed. In particular, sulfonium salts of salicylic acid or β-hydroxycarboxylic acid (Patent Document 4), salicylic acid derivatives (Patent Documents 5, 6), fluorosalicylic acid (Patent Document 7), and hydroxynaphthoic acid (Patent Document 8) have been presented.

[0008] Meanwhile, it has been pointed out that the dimensional uniformity of the resist pattern is reduced due to the aggregation of the quencher. It is expected that the dimensional uniformity of the pattern after development will be improved by preventing the aggregation of the quencher within the resist film and homogenizing its distribution. In the salicylic acid-type sulfonium salt-type quencher mentioned above, a structure having multiple hydroxyl groups on the aromatic ring has also been proposed (Patent Documents 6, 9, 10, 11), but having multiple hydroxyl groups results in low solvent solubility, raising concerns about precipitation.

[0009] In response to the demand for further miniaturization, particularly in positive-type resists, swelling caused by the developer occurs during alkali development, and pattern collapse occurs during fine pattern formation. To address these miniaturization challenges, the development of new resist materials is important, and there is a demand for the development of an onium salt type quencher that is effective in suppressing pattern collapse while having good sensitivity and sufficient control of acid diffusion, as well as excellent solvent solubility. Prior art literature

[0010] Patent Document 1: Japanese Patent Publication No. 2006-045311 Patent Document 2: Japanese Patent Publication No. 2006-178317 Patent Document 3: Japanese Patent Publication No. 2007-114431 Patent Document 4: International Publication No. 2018 / 159560 Patent Document 5: Japanese Patent Publication No. 2020-203984 Patent Document 6: Japanese Patent Publication No. 2020-91404 Patent Document 7: Japanese Patent Publication No. 2020-91312 Patent Document 8: Japanese Patent Publication No. 2019-120760 Patent Document 9: International Publication No. 2020 / 195428 Patent Document 10: Japanese Patent Publication Patent Document 11, Publication No. 2022-91525: Japanese Patent Publication No. 2020-152721

[0011] Non-patent literature 1: SPIE Vol. 6520 65203L-1(2007) The problem to be solved

[0012] The present invention has been made in consideration of the above circumstances and aims to provide a novel onium salt for use in a resist composition that is capable of having high sensitivity and excellent resolution, improving LWR (roughness) and CDU (dimensional uniformity), and suppressing the breakdown of the resist pattern, whether in positive or negative type lithography such as far-ultraviolet lithography and EUV lithography. means of solving the problem

[0013] In order to solve the above problem, the present invention,

[0014] We provide an onium salt characterized by being represented by the following general formula (1).

[0015]

[0016] (In the expression, n1 is an integer of 0 or 1. n2 is an integer of 0 to 3. R 1a is a hydrocarbyl group having 1 to 20 carbon atoms that may contain a halogen atom or a heteroatom. n3 is an integer from 0 to 3. R 1b is a hydrocarbyl group having 1 to 36 carbon atoms that may contain heteroatoms. n4 is an integer of 1 or 2. Z + represents an onium cation.)

[0017] In this case, it is useful as a novel onium salt for use in resist compositions that, whether positive or negative type in lithography, have high sensitivity and excellent resolution, improve LWR or CDU, and suppress the breakdown of the resist pattern.

[0018] In addition, it is preferable that the above general formula (1) is represented by the following formula (1-A).

[0019]

[0020] (during food, R 1a , R 1b , n1, n3, n4 and Z + is as above.)

[0021] In this case, it becomes an onium salt that acts more favorably as an acid diffusion control agent included in the resist composition.

[0022] In addition, it is preferable that the above general formula (1) is represented by the following formula (1-B).

[0023]

[0024] (during food, R 1a , R 1b , n3, and Z + is as above.)

[0025] In this case, it becomes an onium salt that acts more favorably as an acid diffusion control agent included in the resist composition.

[0026] Also, Z in the above general formula (1) + It is preferable that it be an onium cation represented by any one of the following general formulas (Cation-1) to (Cation-3).

[0027]

[0028] (Among equations (Cation-1) to (Cation-3), R 11' ~R 19' Each is independently a straight, branched, or cyclic hydrocarbyl group having 1 to 30 carbon atoms, which may contain heteroatoms and may be saturated or unsaturated.

[0029] In this case, it becomes an onium salt that acts particularly well as an acid diffusion control agent included in the resist composition.

[0030] In addition, the present invention provides an acid diffusion control agent comprising the above-mentioned onium salt.

[0031] The onium salt of the present invention is useful as an acid diffusion control agent.

[0032] In addition, the present invention provides a resist composition comprising the acid diffusion control agent described above.

[0033] By including the aforementioned acid diffusion control agent, it becomes a good resist composition.

[0034] In addition, it is desirable to include an acid-generating agent.

[0035] In this case, the above-mentioned onium salt functions as an acid diffusion control agent, and the resist composition of the present invention functions.

[0036] It is preferable that the above acid generating agent generates sulfonic acid, imidic acid, or methic acid.

[0037] If it is like this, it is more suitable as an acid-generating agent.

[0038] In addition, it is desirable that it contains an organic solvent.

[0039] If this is the case, each component can be dissolved, and the applicability of the composition is improved.

[0040] In addition, it is desirable to include a base polymer.

[0041] If it is like this, it is suitable as a resist composition.

[0042] It is preferable that the above base polymer comprises repeating units represented by the following general formula (a1) and / or repeating units represented by the following general formula (a2).

[0043]

[0044] (during food, R A Each is independently a hydrogen atom or a methyl group. Y 1 is a linker having 1 to 12 carbon atoms comprising at least one selected from a single bond, a phenylene group or a naphthylene group, or an ester bond and a lactone ring. 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond, or an ester bond. R 11 and R 12 are each independently mountain instability phases. R 13It is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 14 is a single bond or an alkandyl group having 1 to 6 carbon atoms, and some of its carbon atoms may be substituted by ether or ester bonds. a is 1 or 2. b is an integer from 0 to 4, provided that 1 ≤ a + b ≤ 5.)

[0045] If so, it is suitable as a positive-type resist composition containing acid instability groups.

[0046] It is preferable that the above resist composition is a chemically amplified positive type resist composition.

[0047] The resist composition of the present invention can function as a chemically amplified positive type resist composition.

[0048] It is also desirable that the above base polymer does not contain acid unstable groups.

[0049] If this is the case, it becomes suitable as a negative-type resist composition without containing acid instability groups.

[0050] It is preferable that the above resist composition is a chemically amplified negative type resist composition.

[0051] The resist composition of the present invention can function as a chemically amplified negative type resist composition.

[0052] It is preferable that the above base polymer further comprises at least one type selected from repeating units represented by the following general formulas (f1) to (f3).

[0053]

[0054] (during food, R A are each independently a hydrogen atom or a methyl group. Z 1is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, an ester bond, or a group having 7 to 18 carbon atoms obtained by a combination thereof, or -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -is. Z 11 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by a combination thereof, and may include a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -OC(=O)- is. Z 31 is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by a combination thereof, and may include a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine atom. Z 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethandiyl group, or a carbonyl group. Z 5 is a single bond, methylene group, ethylene group, phenylene group, fluorinated phenylene group, phenylene group substituted with a trifluoromethyl group, -OZ 51 -, -C(=O)-OZ 51 - or -C(=O)-NH-Z 51 -is. Z 51 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may also be a combination thereof, and may include a carbonyl group, an ester bond, an ether bond, a halogen atom, and / or a hydroxyl group. 21 ~R 28is a hydrocarbyl group having 1 to 20 carbon atoms, which may each independently contain a halogen atom or a heteroatom. Also, R 23 and R 24 or R 26 and R 27 They may be bonded to each other and form a ring together with the sulfur atoms to which they bond. M - is a non-nucleated counterion.)

[0055] If so, it functions as an acid generator within the base polymer.

[0056] In addition, it is desirable to include a surfactant.

[0057] If this is the case, the applicability of the resist composition can be improved or controlled.

[0058] In addition, the present invention provides a pattern forming method comprising the steps of: forming a resist film on a substrate using the resist composition described above; exposing the resist film to high-energy rays; and developing the exposed resist film using a developer.

[0059] With this pattern formation method, a good pattern can be formed.

[0060] As the above high-energy rays, KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet light with a wavelength of 3 to 15 nm can be used.

[0061] By using these high-energy lines, finer and better patterns can be formed. Effects of the invention

[0062] The novel onium salt of the present invention functions well as an acid diffusion control agent (quencher) within the resist composition, allowing for the construction of a high-resolution pattern profile with high sensitivity and excellent dissolution contrast, resulting in a small LWR or CDU and excellent rectangularity. Furthermore, by suppressing swelling of the resist pattern during alkali development and enabling the formation of a pattern resistant to collapse, the present invention provides a resist composition using the novel onium salt of the present invention, which is excellent for fine pattern formation, and a method for forming a pattern using the resist composition. Specific details for implementing the invention

[0063] As mentioned above, there was a need to develop an onium salt type quencher that has good sensitivity, sufficiently controls acid diffusion, excellent solvent solubility, and is effective in inhibiting decay.

[0064] The inventors, having repeatedly examined the above objective, discovered that a resist composition comprising an onium salt having a specific structure as an acid diffusion control agent has excellent sensitivity and resolution of the resist film, has a small LWR of the line pattern and CDU of the hole pattern, and furthermore suppresses swelling during development, making it highly effective for precise micro-processing, and thus completed the present invention.

[0065] That is, the present invention is an onium salt characterized by being represented by the following general formula (1).

[0066]

[0067] (In the expression, n1 is an integer of 0 or 1. n2 is an integer of 0 to 3. R 1a is a hydrocarbyl group having 1 to 20 carbon atoms that may contain a halogen atom or a heteroatom. n3 is an integer from 0 to 3. R 1b is a hydrocarbyl group having 1 to 36 carbon atoms that may contain heteroatoms. n4 is an integer of 1 or 2. Z + represents an onium cation.)

[0068] The present invention will be described in detail below, but the invention is not limited to these.

[0069] [Onium salts]

[0070] The onium salt of the present invention is represented by the following general formula (1).

[0071]

[0072] In the above general formula (1), n1 is an integer of 0 or 1. When n1=0, it represents a benzene ring, and when n1=1, it represents a naphthalene ring, but from the perspective of solvent solubility, it is preferable to have a benzene ring with n1=0.

[0073] In the above general formula (1), n2 is an integer from 0 to 3. When n2 is 1 or greater, at least one OH group is a carboxylate group (CO2 - It is desirable that it is bonded to a carbon atom adjacent to the carbon atom bonded to the group. [OH] n2 The substituent indicated by indicates that n2 hydrogen atoms of the benzene ring or naphthalene are substituted with OH groups.

[0074] Among the above general formula (1), R 1ais a hydrocarbyl group having 1 to 20 carbon atoms, which may include a halogen atom or a heteroatom. Some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a halogen atom, and the -CH2- constituting the hydrocarbyl group may be substituted with -O- or -C(=O)-. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include an alkyl group having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, or a tert-butyl group; and a cyclic saturated hydrocarbyl group having 3 to 20 carbon atoms, such as a cyclopropyl group, a cyclopentyl group, a cyclohexyl group, a cyclopropylmethyl group, a 4-methylcyclohexyl group, a cyclohexylmethyl group, a norbornyl group, or adamantyl group. Examples include alkenyl groups having 2 to 20 carbon atoms, such as vinyl groups, allyl groups, propenyl groups, butenyl groups, and hexenyl groups; cyclic unsaturated hydrocarbyl groups having 3 to 20 carbon atoms, such as cyclohexenyl groups; aryl groups having 6 to 20 carbon atoms, such as phenyl groups and naphthyl groups; aryl groups having 7 to 20 carbon atoms, such as benzyl groups, 1-phenylethyl groups, and 2-phenylethyl groups; and groups obtained by combining these. In addition, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing 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, and as a result, 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, a haloalkyl group, etc. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms, but among these, it is preferable to have fluorine or iodine atoms.

[0075] In the above general formula (1), n3 is an integer from 0 to 3. When n3≥2, multiple R 1a They may bond with each other and form a ring structure together with the carbon atoms they bond to. Specifically, examples of ring structures formed include five-membered and six-membered ring structures, but are not limited to these.

[0076] Among the above general formula (1), R 1b is a hydrocarbyl group having 1 to 36 carbon atoms, which may include heteroatoms. Some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with halogen atoms, and the -CH2- constituting the hydrocarbyl group may be substituted with -O- or -C(=O)-. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include R 1a Examples include things like this.

[0077] In the above general formula (1), n4 is an integer of 1 or 2, but from the perspective of raw material procurement, n4 is preferably 1.

[0078] In addition, it is preferable that the above general formula (1) be represented by the following formula (1-A), and in particular, since salicylic acid has the effect of inhibiting acid diffusion through intramolecular hydrogen bonding between the carboxylic acid and the hydroxyl group, it is more preferable that it be represented by the following general formula (1-B).

[0079]

[0080]

[0081] (during food, R 1a , R 1b , n1, n3, n4 and Z + is as above.)

[0082] If the structure represented by the above general formula (1) is the structure represented by the above formula (1-A), it becomes an onium salt that acts better as an acid diffusion control agent included in the resist composition, and if the structure represented by the above general formula (1-A) is the structure represented by the above general formula (1-B), it becomes an onium salt that acts even better.

[0083] Examples of anions of the onium salt represented by the above general formula (1) include those shown below, but are not limited to these.

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096] Among the above general formula (1), Z + represents an onium cation. Specifically, examples include sulfonium cations, iodonium cations, ammonium cations, phosphonium cations, etc., but it is preferable to use the sulfonium cation, iodonium cation, or ammonium cation shown below.

[0097] Among the above general formula (1), Z + It is preferable that it be represented by any one of the following general formulas (Cation-1) to (Cation-3).

[0098]

[0099] Among the above general formulas (Cation-1) to (Cation-3), R 11' ~R 19' Each is a hydrocarbyl group having 1 to 30 carbon atoms, which may independently contain heteroatoms. The above hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-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; and aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl groups. Examples include groups obtained by combining these, but an aryl group is preferred. Additionally, some of the hydrogen atoms of the hydrocarbyl group may be substituted with heteroatom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and heteroatom-containing groups such as oxygen atoms, sulfur atoms, and nitrogen atoms may be interposed between the carbon atoms of these groups, and as a result, may include hydroxyl groups, cyano groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sulfone rings, carboxylic acid anhydrides, haloalkyl groups, etc.

[0100] Also, R 11' and R 12' They may combine with each other to form a ring together with the sulfur atom to which they combine. In this case, examples of sulfonium cations represented by formula (Cation-1) include those represented by the following formula.

[0101]

[0102] (In the food, the dashed line is R 13 It is a connection point with.)

[0103] Examples of cations of sulfonium salts represented by formula (Cation-1) include those shown below, but are not limited thereto.

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[0117]

[0118]

[0119]

[0120]

[0121]

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129] Examples of iodine cations represented by the above general formula (Cation-2) include those shown below, but are not limited to these.

[0130]

[0131]

[0132] Examples of ammonium cations represented by the above general formula (Cation-3) include those shown below, but are not limited thereto.

[0133]

[0134] Specific structures of the onium salt of the present invention may include any combination of the anion and cation described above.

[0135] The onium salt of the present invention can be synthesized, for example, by ion-exchanging a hydrochloride or carbonate having an onium cation with a corresponding aromatic carboxylate anion.

[0136] When the onium salt of the present invention is coexisted with a strong acid-generating onium salt such as sulfonic acid, imidic acid, or methic acid (hereinafter collectively defined as strong acid), the corresponding carboxylic acid and strong acid are generated upon light irradiation. Meanwhile, in areas with low exposure levels, a large amount of undecomposed onium salt remains. Strong acid functions as a catalyst to induce a deprotection reaction of the base polymer, but the onium salt of the present invention hardly causes a deprotection reaction. The strong acid undergoes ion exchange with the remaining carboxylic acid sulfonium salt to become the onium salt of the strong acid, and instead, the carboxylic acid is released. In other words, through ion exchange, the strong acid is neutralized by the carboxylate onium salt. That is, the onium salt of the present invention functions as a quencher (acid diffusion control agent). This onium salt-type quencher generally tends to result in a smaller LWR of the resist pattern compared to a quencher using an amine compound.

[0137] Salt exchange between the strong acid and the onium carboxylate is repeated countless times. The location where the strong acid is generated at the end of the exposure is different from the location where the initial strong acid-generating onium salt exists. It is inferred that as the cycle of acid generation and salt exchange caused by light is repeated several times, the acid generation points become averaged, and consequently, the LWR of the resist pattern after development decreases.

[0138] Furthermore, a structural feature of the onium salt of the present invention is that it has a sulfonic acid ester structure in the anion. Due to the electron withdrawal effect of the sulfonic acid ester structure, the acidity of the aromatic carboxylic acid, which is the conjugate acid of the anion, is appropriately improved. As a result, the difference in acidity with that of a strong acid is appropriately reduced compared to a conventional aromatic carboxylic acid. Since the difference in acidity with that of a strong acid is reduced, salt exchange between the strong acid and the onium carboxylate salt at the interface between the exposed and unexposed parts becomes easier to occur, and the pattern shape becomes smooth, thereby improving the LWR. In addition, the sulfonic acid ester structure contains multiple heteroatoms and has multiple lone electron pairs. Therefore, the protons of the generated acid and the lone electron pairs interact electrostatically, thereby suppressing excessive acid diffusion of the generated acid into the unexposed part. Due to these synergistic effects, acid diffusion is highly suppressed, and a resist composition with a good pattern shape can be provided.

[0139] [Resist composition]

[0140] The present invention provides a resist composition comprising an acid diffusion control agent comprising the above-mentioned onium salt. The resist composition may include a base polymer, an acid generator, an organic solvent, and other components. Each component will be described below.

[0141] [Acid Diffusion Control Agent]

[0142] The present invention provides an acid diffusion control agent characterized by including the above-mentioned onium salt.

[0143] As described above, the onium salt of the present invention functions as an acid diffusion control agent for a resist composition, and it is preferable that the acid diffusion control agent containing the onium salt of the present invention be included in the resist composition.

[0144] As described above, due to the structural characteristics of the onium salt of the present invention, salt exchange between the strong acid and the onium carboxylate salt at the interface between the exposed and unexposed regions becomes easier to occur, thereby facilitating the smooth pattern shape and improving the LWR. Furthermore, the protons of the generated acid and the lone electron pairs of the onium salt electrostatically interact, thereby suppressing excessive acid diffusion of the generated acid into the unexposed region. Through these synergistic effects, acid diffusion is highly suppressed, thereby providing a resist composition with a good pattern shape.

[0145] The content of the onium salt (acid diffusion control agent) of the present invention in the above resist composition is preferably 0.001 to 50 parts by mass with respect to 100 parts by mass of the base polymer described below, and more preferably 0.01 to 40 parts by mass. The onium salt of the present invention may be used alone or in combination of two or more types.

[0146] In addition, the acid diffusion control agent of the present invention may be combined with one or more acid diffusion control agents (blend quenchers) other than the present invention in any ratio, as described below. The blend quenchers may be known acid diffusion control agents and are not particularly limited. The total content of the combined acid diffusion control agent is preferably 0.001 to 50 parts by mass, and more preferably 0.01 to 40 parts by mass, with respect to 100 parts by mass of the base polymer.

[0147] [Base Polymer]

[0148] The resist composition of the present invention may include a base polymer. In the case of a positive-type resist composition, the base polymer includes a repeating unit comprising an acid unstable group. As the repeating unit comprising an acid unstable group, a repeating unit represented by the following general formula (a1) (hereinafter also referred to as repeating unit a1) and / or a repeating unit represented by the following general formula (a2) (hereinafter also referred to as repeating unit a2) are preferred.

[0149]

[0150] Among the above general formulas (a1) and (a2), R A Each is independently a hydrogen atom or a methyl group. Y 1 is a linker having 1 to 12 carbon atoms comprising at least one selected from a single bond, a phenylene group or a naphthylene group, or an ester bond and a lactone ring. 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond, or an ester bond. R 11 and R 12 are each independently acid instability groups. Additionally, when the base polymer includes repeating unit a1 and repeating unit a2 together, R 11 and R 12 It is fine whether they are identical or different. R 13 It is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 14 is a single bond or an alkandyl group having 1 to 6 carbon atoms, and some of its carbon atoms may be substituted by ether bonds or ester bonds. a is 1 or 2. b is an integer from 0 to 4, provided that 1 ≤ a + b ≤ 5.

[0151] Monomers that provide the repeating unit a1 include those shown below, but are not limited thereto. Also, among the following formulas, R A and R 11 It is as above.

[0152]

[0153] Monomers that provide the repeating unit a2 are those shown below, but are not limited thereto. Also, among the following formulas, R A and R 12 It is as above.

[0154]

[0155] R of the above general formulas (a1) and (a2) 11 and R 12 Examples of acid instability groups indicated by [this] include those described in Japanese Patent Publication No. 2013-80033 and Japanese Patent Publication No. 2013-83821.

[0156] Typically, the above acid instability group can be represented by the following general formulas (AL-1) to (AL-3).

[0157]

[0158] (In the equation, dashed lines are joint points.)

[0159] Among the above general formulas (AL-1) and (AL-2), R L1 and R L2 Each is independently a hydrocarbyl group having 1 to 40 carbon atoms and may contain heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be in a straight chain, branched chain, or cyclic form. As for the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 40 carbon atoms is preferred, and a saturated hydrocarbyl group having 1 to 20 carbon atoms is more preferred.

[0160] In the above general formula (AL-1), c is an integer from 0 to 10, and is preferably an integer from 1 to 5.

[0161] Among the above general formula (AL-2), R L3 and R L4 Each is independently a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, or fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be straight, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 20 carbon atoms is preferred. In addition, R L2 , R L3 and R L4Any two of them may combine with each other to form a ring having 3 to 20 carbon atoms together with the carbon atom or a carbon atom and an oxygen atom to which they combine. As the ring, a ring having 4 to 16 carbon atoms is preferred, and a ring is particularly preferred.

[0162] Among the above general formula (AL-3), R L5 , R L6 and R L7 Each is independently a hydrocarbyl group having 1 to 20 carbon atoms, and may contain heteroatoms such as oxygen, sulfur, nitrogen, or fluorine atoms. The hydrocarbyl group may be saturated or unsaturated, and may be straight, branched, or cyclic. As the hydrocarbyl group, a saturated hydrocarbyl group having 1 to 20 carbon atoms is preferred. In addition, R L5 , R L6 and R L7 Any two of them may combine with each other to form a ring having 3 to 20 carbon atoms together with the carbon atoms to which they combine. As the ring, a ring having 4 to 16 carbon atoms is preferred, and a ring is particularly preferred.

[0163] In the case where the base polymer of the above resist composition includes repeating units a1 and a2, it is a chemically amplified positive type resist composition.

[0164] It is also preferable that the base polymer of the above resist composition does not contain acid unstable groups, in which case the resist composition is a chemically amplified negative type resist composition.

[0165] The above base polymer may include a repeating unit b comprising a phenolic hydroxyl group as an adhesion group. Examples of monomers providing the repeating unit b include those shown below, but are not limited thereto. In addition, among the following formulas, R A It is as above.

[0166]

[0167]

[0168]

[0169] The above base polymer may include a repeating unit c comprising, as another adhesion group, a hydroxyl group other than a phenolic hydroxyl group, a lactone ring, a sulfone ring, an ether link, an ester link, a sulfonic acid ester link, a carbonyl group, a sulfonyl group, a cyano group, and / or a carboxyl group. Examples of monomers imparting the repeating unit c include those shown below, but are not limited thereto. In addition, among the following formulas, R A It is as above.

[0170]

[0171]

[0172]

[0173]

[0174]

[0175]

[0176]

[0177]

[0178]

[0179] The above base polymer may include a repeating unit d derived from indene, benzofuran, benzothiophene, acenaphtylene, chromone, coumarin, norbornadiene, or derivatives thereof. Examples of monomers providing the repeating unit d include those listed below, but are not limited thereto.

[0180]

[0181] The above base polymer may include repeating unit e derived from styrene, vinylnaphthalene, vinylanthracene, vinylpyrene, methyleneindane, vinylpyridine, or vinylcarbazole.

[0182] The above base polymer may include a repeating unit f derived from an onium salt containing a polymerizable unsaturated bond. Preferred repeating unit f may include a repeating unit represented by the following general formula (f1) (hereinafter also referred to as repeating unit f1), a repeating unit represented by the following general formula (f2) (hereinafter also referred to as repeating unit f2), and a repeating unit represented by the following general formula (f3) (hereinafter also referred to as repeating unit f3). Additionally, repeating units f1 to f3 may be used individually or in combination of two or more types.

[0183]

[0184] Among the above general formulas (f1) to (f3), R A are each independently a hydrogen atom or a methyl group. Z 1 is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, an ester bond, or a group having 7 to 18 carbon atoms obtained by a combination thereof, or -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -is. Z 11 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by a combination thereof, and may include a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -OC(=O)- is. Z 31 is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by a combination thereof, and may include a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine atom. Z 4is a methylene group, a 2,2,2-trifluoro-1,1-ethandiyl group, or a carbonyl group. Z 5 is a single bond, methylene group, ethylene group, phenylene group, fluorinated phenylene group, phenylene group substituted with a trifluoromethyl group, -OZ 51 -, -C(=O)-OZ 51 - or -C(=O)-NH-Z 51 -is. Z 51 The group is an aliphatic hydrocarbylene group having 1 to 15 carbon atoms, preferably 1 to 6, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and a combination thereof may also be present, and may include a carbonyl group, an ester bond, an ether bond, a halogen atom, and / or a hydroxyl group.

[0185] Among the above general formulas (f1) to (f3), R 21 ~R 28 Each is a hydrocarbyl group having 1 to 20 carbon atoms, which may independently contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be straight, branched, or cyclic. Specific examples thereof include R in the description of the above general formulas (Cation-1) and (Cation-3). 11' ~R 19' Examples of hydrocarbyl groups represented by [] may include those exemplified. The above hydrocarbyl group may have some or all of its hydrogen atoms substituted with a group containing heteroatoms such as oxygen, sulfur, nitrogen, or halogen atoms, or some of the carbon atoms of these groups substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, 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, a haloalkyl group, etc. Additionally, R 23 and R 24or R 26 and R 27 They may be bonded to each other to form a ring together with the sulfur atom to which they bond. In this case, as the ring, R in the explanation of the general formula (Cation-1) above 11' and R 12' Examples of rings that can be formed by combining with the sulfur atoms they combine with, such as those exemplified, can be given.

[0186] Among the above general formula (f1), M - Examples of the above non-nucleated counterions include: halide ions such as chloride ions and bromide ions; fluoroalkylsulfonate ions such as trilate ions, 1,1,1-trifluoroethanesulfonate ions, and nonafluorobutanesulfonate ions; arylsulfonate ions such as tosylate ions, benzenesulfonate ions, 4-fluorobenzenesulfonate ions, and 1,2,3,4,5-pentafluorobenzenesulfonate ions; alkylsulfonate ions such as mesylate ions and butanesulfonate ions; imide ions such as bis(trifluoromethylsulfonyl)imide ions, bis(perfluoroethylsulfonyl)imide ions, and bis(perfluorobutylsulfonyl)imide ions; and methide ions such as tris(trifluoromethylsulfonyl)methide ions and tris(perfluoroethylsulfonyl)methide ions.

[0187] Other examples of the above-mentioned non-nucleated counterions include sulfonate ions in which the α position is substituted with a fluorine atom represented by the following general formula (f1-1), and sulfonate ions in which the α position is substituted with a fluorine atom and the β position is substituted with a trifluoromethyl group represented by the following general formula (f1-2).

[0188]

[0189] In the above general formula (f1-1), R 31is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and the hydrocarbyl group may include an ether bond, an ester bond, a carbonyl group, a lactone ring, or a fluorine atom. The hydrocarbyl group may be saturated or unsaturated, and may be straight, branched, or cyclic. As a specific example, R in formula (3A') described below. 111 Examples include the hydrocarbyl group indicated by [this].

[0190] In the above general formula (f1-2), R 32 is a hydrogen atom, a hydrocarbyl group having 1 to 30 carbon atoms, or a hydrocarbyl carbonyl group having 6 to 20 carbon atoms, and the hydrocarbyl group and hydrocarbyl carbonyl group may include an ether bond, an ester bond, a carbonyl group, or a lactone ring. The hydrocarbyl portion of the hydrocarbyl group and hydrocarbyl carbonyl group may be saturated or unsaturated, and may be straight, branched, or cyclic. As a specific example, R in formula (3A') described below. 111 Examples include the hydrocarbyl group indicated by [this].

[0191] Examples of monomer cations that provide the repeating unit f1 include those shown below, but are not limited thereto. Also, among the following formulas, R A It is as above.

[0192]

[0193] Specific examples of monomer cations that impart repeating units f2 and f3 include those exemplified as cations of sulfonium salts represented by the general formula (Cation-1) above.

[0194] Examples of monomer anions that provide the repeating unit f2 include those shown below, but are not limited thereto. Also, among the following formulas, R A It is as above.

[0195]

[0196]

[0197]

[0198]

[0199]

[0200]

[0201]

[0202]

[0203]

[0204]

[0205]

[0206]

[0207] Examples of monomer anions that provide the repeating unit f3 include those shown below, but are not limited thereto. Also, among the following formulas, R A It is as above.

[0208]

[0209]

[0210] The above repeating units f1 to f3 function as acid generators. By incorporating acid generators into the polymer main chain, acid diffusion is minimized, thereby preventing a decrease in resolution caused by the blurring of acid diffusion. Furthermore, LWR and CDU are improved as the acid generators are uniformly dispersed. Additionally, when using a base polymer containing repeating unit f, the formulation of the additive acid generator described later can be omitted.

[0211] In the above base polymer, the content ratio of repeating units a1, a2, b, c, d, e, f1, f2, and f3 is preferably 0≤a1≤0.9, 0≤a2≤0.9, 0≤a1+a2≤0.9, 0≤b≤0.9, 0≤c≤0.9, 0≤d≤0.5, 0≤e≤0.5, 0≤f1≤0.5, 0≤f2≤0.5, 0≤f3≤0.5, and 0≤f1+f2+f3≤0.5, and preferably 0≤a1≤0.8, 0≤a2≤0.8, 0≤a1+a2≤0.8, 0≤b≤0.8, 0≤c≤0.8, 0≤d≤0.4, 0≤e≤0.4, 0≤f1≤0.4, and 0≤f2≤0.4. 0≤f3≤0.4, 0≤f1+f2+f3≤0.4 is more desirable, and 0≤a1≤0.7, 0≤a2≤0.7, 0≤a1+a2≤0.7, 0≤b≤0.7, 0≤c≤0.7, 0≤d≤0.3, 0≤e≤0.3, 0≤f1≤0.3, 0≤f2≤0.3, 0≤f3≤0.3, 0≤f1+f2+f3≤0.3 is even more desirable, provided that a1+a2+b+c+d+f1+f2+f3+e=1.0.

[0212] To synthesize the above base polymer, for example, a monomer providing the repeating unit described above can be polymerized by adding a radical polymerization initiator to an organic solvent and heating it.

[0213] Examples of organic solvents used during polymerization include toluene, benzene, tetrahydrofuran (THF), diethyl ether, and dioxane. Examples of polymerization initiators include 2,2'-azobis(isobutyronitrile) (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The temperature during polymerization is preferably 50 to 80°C. The reaction time is preferably 2 to 100 hours, more preferably 5 to 20 hours.

[0214] When copolymerizing monomers containing hydroxyl groups, the hydroxyl groups may be substituted with acetal groups that are easily deprotected by acids such as ethoxyethoxy groups during polymerization and then deprotected with a weak acid and water after polymerization, or they may be substituted with acetyl groups, formyl groups, pivaloyyl groups, etc. and then alkaline hydrolysis may be performed after polymerization.

[0215] In the case of copolymerizing hydroxystyrene or hydroxyvinyl naphthalene, acetoxystyrene or acetoxyvinyl naphthalene may be used instead of hydroxystyrene or hydroxyvinyl naphthalene, and after polymerization, the acetoxy group may be deprotected by the above alkaline hydrolysis to obtain hydroxystyrene or hydroxyvinyl naphthalene.

[0216] Water ammonia, triethylamine, etc., may be used as the base during alkaline hydrolysis. In addition, the reaction temperature is preferably -20 to 100°C, more preferably 0 to 60°C. The reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

[0217] The above base polymer has a polystyrene-equivalent weight average molecular weight (Mw) by gel permeation chromatography (GPC) using THF as a solvent, preferably 1,000 to 500,000, and more preferably 2,000 to 30,000. If Mw is in the above range, the heat resistance of the resist film and solubility in an alkaline developer are good.

[0218] In addition, when the molecular weight distribution (Mw / Mn) of the base polymer is sufficiently narrow, there is no risk of foreign matter being visible on the pattern or the pattern shape deteriorating after exposure, as there are no low or high molecular weight polymers. Since the influence of Mw or Mw / Mn tends to increase as the pattern rule becomes finer, in order to obtain a resist composition suitable for use with fine pattern dimensions, it is preferable that the Mw / Mn of the base polymer be narrowly dispersed, specifically 1.0 to 2.0, and particularly 1.0 to 1.5. The molecular weight distribution is preferably measured together with the weight-average molecular weight.

[0219] The above base polymer may include two or more polymers with different composition ratios, Mw, and Mw / Mn.

[0220] [Acid generator]

[0221] The resist composition of the present invention may include an acid generator that generates a strong acid (hereinafter also referred to as an additive acid generator). The generated acid is preferably a strong acid. The strong acid referred to herein means a compound having sufficient acidity to cause a deprotection reaction of the acid unstable groups of the base polymer in the case of a chemically amplified positive type resist composition, and a compound having sufficient acidity to cause a polarity change reaction or a crosslinking reaction by the acid in the case of a chemically amplified negative type resist composition. By including such an acid generator, the above-described onium salt functions as a quencher, and the resist composition of the present invention can function as a chemically amplified positive type resist composition or a chemically amplified negative type resist composition.

[0222] Examples of the above acid-generating agents include compounds that generate acid in response to active light or radiation (photo-generating agents). As for the photo-generating agent, any compound that generates acid upon irradiation with high-energy rays is acceptable, but it is preferable to generate sulfonic acid, imidic acid, or methic acid. Suitable photo-generating agents include sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, and oxime-O-sulfonate type acid-generating agents. Specific examples of photo-generating agents include those described in paragraphs

[0122] to

[0142] of Japanese Patent Publication No. 2008-111103.

[0223] In addition, as a photocatalytic agent, a sulfonium salt represented by the following general formula (3-1) or an iodium salt represented by the following general formula (3-2) can also be suitably used.

[0224]

[0225] Among the above general formulas (3-1) and (3-2), R 101 ~R 105 is a hydrocarbyl group having 1 to 20 carbon atoms, which may each independently contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be straight, branched, or cyclic. As a specific example, R in the description of formulas (Cation-1) to (Cation-3) 11' ~R 19' Examples such as the hydrocarbyl group represented by can be cited. Also, R 101 and R 102 They may bond with each other to form a ring together with the sulfur atom to which they bond. In this case, as the ring, R in the explanation of Formula (Cation-1) 11' and R 12' Examples of rings that can be formed by combining with the sulfur atoms they combine with, such as those exemplified, can be given.

[0226] Examples of cations of sulfonium salts represented by the above general formula (3-1) include those exemplified as cations of sulfonium salts represented by formula (Cation-1), but are not limited thereto.

[0227] Examples of cations of iodium salts represented by the above general formula (3-2) include those exemplified as cations of iodium salts represented by formula (Cation-2), but are not limited to these.

[0228] Among the above general formulas (3-1) and (3-2), Xa - is an anion selected from the following formulas (3A) to (3D).

[0229]

[0230] Among the above general formula (3A), R fa is a hydrocarbyl group having 1 to 40 carbon atoms, which may include a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be straight, branched, or cyclic. As a specific example, R in formula (3A') described below. 111 Examples include the hydrocarbyl group indicated by [this].

[0231] As for the anion represented by the above general formula (3A), it is preferable that it be represented by the following general formula (3A').

[0232]

[0233] Among the above general formula (3A'), R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R 111The hydrocarbyl group having 1 to 38 carbon atoms may include heteroatoms. As the heteroatom, oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc. are preferred, and oxygen atoms are more preferred. As for the hydrocarbyl group, it is particularly preferred to have 6 to 30 carbon atoms in order to obtain high resolution in forming fine patterns.

[0234] R 111 The hydrocarbyl group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 38 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecyl, and icosanyl groups; Examples include cyclic saturated hydrocarbyl groups having 3 to 38 carbon atoms, such as cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, 1-adamantylmethyl group, norbornyl group, norbornylmethyl group, tricyclodecanyl group, tetracyclododecanyl group, tetracyclododecanylmethyl group, and dicyclohexylmethyl group; unsaturated aliphatic hydrocarbyl groups having 2 to 38 carbon atoms, such as allyl group and 3-cyclohexenyl group; aryl groups having 6 to 38 carbon atoms, such as phenyl group, 1-naphthyl group, and 2-naphthyl group; aryl groups having 7 to 38 carbon atoms, such as benzyl group and diphenylmethyl group; and groups obtained by combining these.

[0235] In addition, some or all of the hydrogen atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the carbon atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., and as a result, they may include hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sulfone rings, carboxylic acid anhydrides, haloalkyl groups, etc. Examples of hydrocarbyl groups containing heteroatoms include tetrahydrofuryl groups, methoxymethyl groups, ethoxymethyl groups, methylthiomethyl groups, acetamide methyl 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.

[0236] The synthesis of a sulfonium salt containing an anion represented by the above general formula (3A') is described in detail in Japanese Patent Publication No. 2007-145797, Japanese Patent Publication No. 2008-106045, Japanese Patent Publication No. 2009-7327, Japanese Patent Publication No. 2009-258695, etc. In addition, sulfonium salts described in Japanese Patent Publication No. 2010-215608, Japanese Patent Publication No. 2012-41320, Japanese Patent Publication No. 2012-106986, Japanese Patent Publication No. 2012-153644, etc. are also suitably used.

[0237] Examples of anions represented by the above general formula (3A) include those exemplified as anions represented by formula (1A) in Japanese Patent Publication No. 2018-197853.

[0238] Among the above general formula (3B), R fb1 and R fb2is a hydrocarbyl group having 1 to 40 carbon atoms, which may each independently contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be straight, branched, or cyclic. Specific examples thereof include R in the general formula (3A') above. 111 Examples such as the hydrocarbyl group represented by can be cited. R fb1 and R fb2 Preferably, it is a fluorine atom or a straight-chain fluorinated alkyl group having 1 to 4 carbon atoms. In addition, R fb1 and R fb2 They combine with each other, and the groups to which they combine (-CF2-SO2-N - It may form a ring together with -SO2-CF2-), and in this case, R fb1 and R fb2 It is preferable that the group obtained by combining with each other is a fluorinated ethylene group or a fluorinated propylene group.

[0239] Among the above general formula (3C), R fc1 , R fc2 and R fc3 Each is a hydrocarbyl group having 1 to 40 carbon atoms, which may independently contain a fluorine atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be straight, branched, or cyclic. Specific examples thereof include R in the general formula (3A'). 111 Examples such as the hydrocarbyl group represented by can be cited. R fc1 , R fc2 and R fc3 Preferably, it is a fluorine atom or a straight-chain fluorinated alkyl group having 1 to 4 carbon atoms. In addition, R fc1 and R fc2 They combine with each other, and the groups to which they combine (-CF2-SO2-C - It may form a ring together with -SO2-CF2-), and in this case, R fc1 and R fc2It is preferable that the group obtained by combining with each other is a fluorinated ethylene group or a fluorinated propylene group.

[0240] Among the above general formula (3D), R fd is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. The hydrocarbyl group may be saturated or unsaturated, and may be straight, branched, or cyclic. A specific example thereof is R in formula (3A'). 111 Examples of hydrocarbilic groups represented by [this] can be cited, such as those exemplified.

[0241] The synthesis of a sulfonium salt containing an anion represented by the above general formula (3D) is described in detail in Japanese Patent Publication No. 2010-215608 and Japanese Patent Publication No. 2014-133723.

[0242] Examples of anions represented by the above general formula (3D) include those exemplified as anions represented by formula (1D) in Japanese Patent Publication No. 2018-197853.

[0243] In addition, the photogenerator containing an anion represented by the above general formula (3D) does not have a fluorine atom at the α position of the sulfon group, but has two trifluoromethyl groups at the β position, and thus has sufficient acidity to cleave acid unstable groups in the base polymer. For this reason, it can be used as a photogenerator.

[0244] As a mine-generating agent, the one represented by the following general formula (4) can also be suitably used.

[0245]

[0246] Among the above general formula (4), R 201 and R 202 R is a hydrocarbyl group having 1 to 30 carbon atoms, which may each independently contain a halogen atom or a heteroatom. 203It is a hydrocarbylene group having 1 to 30 carbon atoms that may contain heteroatoms. Also, R 201 , R 202 and R 203 Any two of them may combine with each other to form a ring together with the sulfur atom to which they combine. In this case, as the ring, R in the explanation of the general formula (Cation-1) above 11 ' and R 12' Examples of rings that can be formed by combining with the sulfur atoms they combine with, such as those exemplified, can be given.

[0247] R 201 and R 202 The hydrocarbyl group represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 30 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, oxanorbornyl, and tricyclo[5.2.1.0 2,6Examples include cyclic saturated hydrocarbyl groups having 3 to 30 carbon atoms, such as decanyl groups and adamantyl groups; aryl groups having 6 to 30 carbon atoms, such as phenyl groups, methylphenyl groups, ethylphenyl groups, n-propylphenyl groups, isopropylphenyl groups, n-butylphenyl groups, isobutylphenyl groups, sec-butylphenyl groups, tert-butylphenyl groups, naphthyl groups, methylnaphthyl groups, ethylnaphthyl groups, n-propylnaphthyl groups, isopropylnaphthyl groups, n-butylnaphthyl groups, isobutylnaphthyl groups, sec-butylnaphthyl groups, tert-butylnaphthyl groups, and anthracenyl groups; and groups obtained by combining these. In addition, some or all of the hydrogen atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, etc., and some of the carbon atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, etc., and as a result, they may include hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sulfone rings, carboxylic acid anhydrides, haloalkyl groups, etc.

[0248] R 203The hydrocarbylene group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkanediyl groups having 1 to 30 carbon atoms, such as methanediyl group, ethane-1,1-diyl group, ethane-1,2-diyl group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, and heptadecane-1,17-diyl group; Examples include cyclic saturated hydrocarbylene groups having 3 to 30 carbon atoms, such as cyclopentanediyl, cyclohexanediyl, norbornandiyl, and adamantandiyl; arylene groups having 6 to 30 carbon atoms, 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, and tert-butylnaphthylene; and groups obtained by combining these. In addition, some or all of the hydrogen atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, or halogen atoms, and some of the carbon atoms of these groups may be substituted with groups containing heteroatoms such as oxygen atoms, sulfur atoms, or nitrogen atoms, and as a result, they may include hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, carbonyl groups, ether bonds, ester bonds, sulfonic acid ester bonds, carbonate bonds, lactone rings, sulfone rings, carboxylic acid anhydrides, haloalkyl groups, etc. As the heteroatom, an oxygen atom is preferred.

[0249] Among the above general formula (4), L Ais a hydrocarbylene group having 1 to 20 carbon atoms, which may include single bonds, ether bonds, or heteroatoms. The hydrocarbylene group may be saturated or unsaturated, and may be straight, branched, or cyclic. Specific examples thereof include R 203 Examples of hydrocarbylene groups represented as such include those exemplified.

[0250] Among the above general formula (4), X A , X B , X C and X D Each 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.

[0251] In the above general formula (4), d is an integer from 0 to 3.

[0252] As for the mine generator represented by the above general formula (4), it is preferable to represent it by the following general formula (4').

[0253]

[0254] Among the above general formula (4'), L A is as above. R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. R 301 , R 302 and R 303 is a hydrocarbyl group having 1 to 20 carbon atoms, which may each independently contain a hydrogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be straight, branched, or cyclic. A specific example thereof is R in formula (3A'). 111 Examples of hydrocarbyls represented by can be given as those exemplified. x and y are each independently integers from 0 to 5, and z is an integer from 0 to 4.

[0255] Examples of light-generating agents represented by the above general formula (4) include those exemplified by the light-generating agent represented by formula (2) in Japanese Patent Publication No. 2017-026980.

[0256] Among the above photogeneratives, those containing anion represented by the general formula (3A') or (3D) are particularly desirable because they have low acid diffusion and excellent solubility in solvents. Additionally, those represented by formula (4') are particularly desirable because they have very low acid diffusion.

[0257] As the above-mentioned photocatalyst, a sulfonium salt or iodonium salt containing an anion having an aromatic ring substituted with an iodine atom or a bromine atom may be used. Examples of such salts include those represented by the following general formulas (5-1) or (5-2).

[0258]

[0259] In the above general formulas (5-1) and (5-2), p is an integer satisfying 1 ≤ p ≤ 3. q and r are integers satisfying 1 ≤ q ≤ 5, 0 ≤ r ≤ 3, and 1 ≤ q + r ≤ 5. q is preferably an integer satisfying 1 ≤ q ≤ 3, and more preferably 2 or 3. r is preferably an integer satisfying 0 ≤ r ≤ 2.

[0260] Among the above general formulas (5-1) and (5-2), X BI is an iodine atom or a bromine atom, and when p and / or q are 2 or more, they may be the same or different.

[0261] Among the above general formulas (5-1) and (5-2), L 1 It is a saturated hydrocarbylene group having 1 to 6 carbon atoms, which 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.

[0262] Among the above general formulas (5-1) and (5-2), L2 When p is 1, it is a single bond or a divalent linker having 1 to 20 carbon atoms, and when p is 2 or 3, it is a (p+1)valent linker having 1 to 20 carbon atoms, and this linker may include an oxygen atom, a sulfur atom, or a nitrogen atom.

[0263] Among the above general formulas (5-1) and (5-2), R 401 It 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, a bromine atom, a hydroxyl group, an amino group, or an ether bond, an ester bond, or an amide bond, a hydrocarbyl group having 1 to 20 carbon atoms, a hydrocarbyloxy group having 1 to 20 carbon atoms, a hydrocarbyl carbonyl group having 2 to 20 carbon atoms, a hydrocarbyl oxycarbonyl group having 2 to 20 carbon atoms, a hydrocarbyl carbonyloxy group having 2 to 20 carbon atoms, or a hydrocarbyl sulfonyloxy group having 1 to 20 carbon atoms, 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 saturated hydrocarbyl group having 1 to 6 carbon atoms. R 401C is a hydrogen atom or a saturated hydrocarbyl group having 1 to 6 carbon atoms, and may include a halogen atom, a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbylcarbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbylcarbonyloxy group having 2 to 6 carbon atoms. 401Dis an aliphatic hydrocarbyl group having 1 to 16 carbon atoms, an aryl group having 6 to 14 carbon atoms, or an aryl group having 7 to 15 carbon atoms, and may include a halogen atom, a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a saturated hydrocarbyl carbonyl group having 2 to 6 carbon atoms, or a saturated hydrocarbyl carbonyloxy group having 2 to 6 carbon atoms. The aliphatic hydrocarbyl group may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. The saturated hydrocarbyl group, saturated hydrocarbyloxy group, saturated hydrocarbyloxycarbonyl group, saturated hydrocarbyl carbonyl group, and saturated hydrocarbyl carbonyloxyoxy group may be straight-chain, branched, or cyclic. When p and / or r are 2 or more, each R 401 It is fine whether they are the same or different.

[0264] Among these, R 401 As is a 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.

[0265] Among the above general formulas (5-1) and (5-2), Rf 1 ~Rf 4 Each is independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group, but at least one of these is a fluorine atom or a trifluoromethyl group. Also, Rf 1 and Rf 2 It is acceptable for them to combine to form a carbonyl group. In particular, Rf 3 and Rf 4 It is desirable that they are fluorine atoms together.

[0266] Among the above general formulas (5-1) and (5-2), R 402 ~R 406Each is a hydrocarbyl group having 1 to 20 carbon atoms, which may independently contain a halogen atom or a heteroatom. The hydrocarbyl group may be saturated or unsaturated, and may be straight, branched, or cyclic. As a specific example, R in the description of the above general formula (Cation-1) 11' ~R 19' Examples include hydrocarbyl groups represented by . In addition, some or all of the hydrogen atoms of these groups may be substituted with hydroxyl groups, carboxyl groups, halogen atoms, cyano groups, nitro groups, mercapto groups, sulfonyl rings, sulfonate groups, or sulfonium salt-containing groups, and some of the carbon atoms of these groups may be substituted with ether bonds, ester bonds, carbonyl groups, amide bonds, carbonate bonds, or sulfonic acid ester bonds. In addition, R 402 and R 403 They may bond with each other to form a ring together with the sulfur atom to which they bond. In this case, as the ring, R in the explanation of the general formula (Cation-1) above 11' and R 12' Examples include rings that can be formed by combining with each other and the sulfur atoms they combine with, such as those exemplified.

[0267] Examples of cations of the sulfonium salt represented by the above general formula (5-1) include those exemplified as cations of the sulfonium salt represented by the above general formula (Cation-1). Additionally, examples of cations of the iodonium salt represented by the above general formula (5-2) include those exemplified as cations of the iodonium salt represented by the above general formula (Cation-2).

[0268] Examples of anions of the onium salts represented by the above general formulas (5-1) or (5-2) include those shown below, but are not limited thereto. Also, among the following formulas, X BI It is as above.

[0269]

[0270]

[0271]

[0272]

[0273]

[0274]

[0275]

[0276]

[0277]

[0278]

[0279]

[0280]

[0281]

[0282]

[0283]

[0284]

[0285]

[0286]

[0287]

[0288]

[0289]

[0290]

[0291]

[0292] When the resist composition of the present invention includes an additive acid generator, its content is preferably 0.1 to 50 parts by mass with respect to 100 parts by mass of the base polymer, and more preferably 1 to 40 parts by mass. The resist composition of the present invention can function as a chemically amplified resist composition by the base polymer including any one of repeating units f1 to f3 and / or including an additive acid generator.

[0293] [Organic Solvents]

[0294] The resist composition of the present invention may include an organic solvent. The organic solvent is not particularly limited as long as it is capable of dissolving each component described above and each component described below. As for the organic solvent, ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone as described in paragraphs

[0144] to

[0145] of Japanese Patent Publication No. 2008-111103; alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol; and ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether. Examples include esters such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; and lactones such as γ-butyrolactone.

[0295] In the resist composition of the present invention, the content of the organic solvent is preferably 100 to 10,000 parts by mass per 100 parts by mass of the base polymer, and more preferably 200 to 8,000 parts by mass. The organic solvent may be used as a single type or as a mixture of two or more types.

[0296] [Other ingredients]

[0297] The resist composition of the present invention may include, in addition to the components described above, a surfactant, a solubilization inhibitor, a crosslinking agent, a quencher other than the onium salt of the present invention (hereinafter referred to as "other quenchers"), a water repellency enhancer, acetylene alcohols, etc.

[0298] Examples of the above surfactants include those described in paragraphs

[0165] to

[0166] of Japanese Patent Publication No. 2008-111103. By adding a surfactant, the applicability of the resist composition can be further improved or controlled. When the resist composition of the present invention includes the above surfactant, the content thereof is preferably 0.0001 to 10 parts by mass per 100 parts by mass of the base polymer. The above surfactant may be used as a single type or in combination of two or more types.

[0299] In the case where the resist composition of the present invention is of the positive type, by incorporating a dissolution inhibitor, the difference in the dissolution rate between the exposed and unexposed parts can be further increased, thereby further improving the resolution. Examples of the dissolution inhibitor include a compound having a molecular weight preferably 100 to 1,000, more preferably 150 to 800, and containing two or more phenolic hydroxyl groups within the molecule, wherein the hydrogen atoms of the said phenolic hydroxyl groups are substituted by an acid unstable group at a ratio of 0 to 100 mol% overall, or a compound having a carboxyl group within the molecule, wherein the hydrogen atoms of the said carboxyl groups are substituted by an acid unstable group at a ratio of 50 to 100 mol% overall. Specifically, examples include bisphenol A, trisphenol, phenolphthalein, cresol novolac, naphthalenecarboxylic acid, adamantan carboxylic acid, compounds in which the hydrogen atoms of the hydroxyl group and carboxyl group of cholic acid are substituted with acid unstable groups, and are described, for example, in paragraphs

[0155] to

[0178] of Japanese Patent Publication No. 2008-122932.

[0300] When the resist composition of the present invention is of the positive type and includes the solubility inhibitor, the content thereof is preferably 0 to 50 parts by mass per 100 parts by mass of base polymer, and more preferably 5 to 40 parts by mass. The solubility inhibitor may be used alone or in combination of two or more types.

[0301] Meanwhile, when the resist composition of the present invention is of the negative type, a negative pattern can be obtained by adding a crosslinking agent to reduce the dissolution rate of the exposed portion. Examples of the crosslinking agent include epoxy compounds, melamine compounds, guanamine compounds, glycoluryl compounds, urea compounds, isocyanate compounds, azide compounds, or compounds containing double bonds such as alkenyloxy groups, which are substituted with at least one group selected from methylol groups, alkoxymethyl groups, and acyloxymethyl groups. These may be used as additives, but may also be introduced as pendant groups into the polymer side chains. Additionally, compounds containing hydroxyl groups may also be used as crosslinking agents.

[0302] Examples of the above epoxy compounds include tris(2,3-epoxypropyl)isocyanurate, trimethylolmethanetriglycidyl ether, trimethylolpropanetriglycidyl ether, triethylolethanetriglycidyl ether, etc.

[0303] Examples of the above melamine compounds include hexamethylolmelamine, hexamethoxymethylmelamine, a compound in which 1 to 6 methylol groups of hexamethylolmelamine are methoxymethylated or a mixture thereof, hexamethoxyethylmelamine, hexaacyloxymethylmelamine, a compound in which 1 to 6 methylol groups of hexamethylolmelamine are acyloxymethylated or a mixture thereof.

[0304] Examples of the above guanamin compounds include tetramethylolguanamin, tetramethoxymethylguanamin, a compound in which 1 to 4 methylol groups of tetramethylolguanamin are methoxymethylated or a mixture thereof, tetramethoxyethylguanamin, tetraacyloxyguanamin, a compound in which 1 to 4 methylol groups of tetramethylolguanamin are acyloxymethylated or a mixture thereof.

[0305] Examples of the above glycoluryl compounds include tetramethylol glycoluryl, tetramethoxyglycoluryl, tetramethoxymethylglycoluryl, a compound in which 1 to 4 methylol groups of tetramethylol glycoluryl are methoxymethylated or a mixture thereof, a compound in which 1 to 4 methylol groups of tetramethylol glycoluryl are acyloxymethylated or a mixture thereof.

[0306] Examples of the above urea compounds include tetramethylolurea, tetramethoxymethylurea, a compound in which 1 to 4 methylol groups of tetramethylolurea are methoxymethylated or a mixture thereof, tetramethoxyethylurea, etc.

[0307] Examples of the above isocyanate compounds include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, etc.

[0308] Examples of the above azide compounds include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, 4,4'-oxybisazide, etc.

[0309] Examples of compounds containing the above alkenyloxy group include ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl glycol divinyl ether, trimethylolpropane divinyl ether, hexanediol divinyl ether, 1,4-cyclohexanediol divinyl ether, pentaerythritol divinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether, etc.

[0310] When the resist composition of the present invention is of the negative type and includes the crosslinking agent, the content thereof is preferably 0.1 to 50 parts by mass per 100 parts by mass of base polymer, and more preferably 1 to 40 parts by mass. The crosslinking agent may be used alone or in combination of two or more types.

[0311] Examples of other quenchers mentioned above include basic compounds of the conventional form. Examples of basic compounds of the conventional form include primary, secondary, or tertiary aliphatic amines, hybrid amines, aromatic amines, heterocyclic amines, nitrogen-containing compounds having a carboxyl group, nitrogen-containing compounds having a sulfonyl group, nitrogen-containing compounds having a hydroxyl group, nitrogen-containing compounds having a hydroxyphenyl group, alcoholic nitrogen-containing compounds, amides, imides, carbamates, etc. In particular, primary, secondary, or tertiary amine compounds described in paragraphs

[0146] to

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

[0312] In addition, other quenchers include onium salts, such as sulfonium salts, iodonium salts, and ammonium salts, of sulfonic acids and carboxylic acids that are not fluorinated at the α-position, as described in Japanese Patent Publication No. 2008-158339. Sulfonic acids, imidic acids, or methic acids that are fluorinated at the α-position are required to deprotect the acid unstable groups of carboxylic acid esters, but sulfonic acids or carboxylic acids that are not fluorinated at the α-position are released through salt exchange with onium salts that are not fluorinated at the α-position. Sulfonic acids and carboxylic acids that are not fluorinated at the α-position function as quenchers because they do not cause a deprotection reaction.

[0313] Other examples of quenchers include the polymer-type quencher described in Japanese Patent Publication No. 2008-239918. This improves the rectangularity of the resist pattern by orienting it on the surface of the resist film. The polymer-type quencher also has the effect of preventing film reduction of the pattern or rounding of the pattern top when a protective film for immersion exposure is applied.

[0314] When the resist composition of the present invention includes other quenchers, the content thereof is preferably 0 to 5 parts by mass per 100 parts by mass of base polymer, and more preferably 0 to 4 parts by mass. The other quenchers may be used as a single type or in combination of two or more types.

[0315] The above-mentioned water repellency enhancer improves the water repellency of the surface of a resist film and can be used in immersion lithography without a top coat. As for the above-mentioned water repellency enhancer, polymers containing alkyl fluoride groups, polymers containing 1,1,1,3,3,3-hexafluoro-2-propanol residues of a specific structure are preferred, and it is more preferable that they are exemplified in Japanese Patent Publication No. 2007-297590, Japanese Patent Publication No. 2008-111103, etc. The above-mentioned water repellency enhancer needs to be dissolved in an alkaline developer or an organic solvent developer. The above-mentioned water repellency enhancer having specific 1,1,1,3,3,3-hexafluoro-2-propanol residues has good solubility in the developer. A polymer containing repeating units including amino groups or amine salts as a water-repellent enhancer is highly effective in preventing the evaporation of acid during post-exposure bake (PEB) and thus preventing defects in the opening of hole patterns after development. When the resist composition of the present invention includes the water-repellent enhancer, its content is preferably 0 to 20 parts by mass per 100 parts by mass of base polymer, and more preferably 0.5 to 10 parts by mass. The water-repellent enhancer may be used as a single type or in combination of two or more types.

[0316] Examples of the above acetylene alcohols include those described in paragraphs

[0179] to

[0182] of Japanese Patent Publication No. 2008-122932. When the resist composition of the present invention includes the above acetylene alcohols, the content thereof is preferably 0 to 5 parts by mass per 100 parts by mass of the base polymer. The above acetylene alcohols may be used as a single type or in combination of two or more types.

[0317] The resist composition of the present invention can improve LWR or CDU. This is due to the synergistic effect of the onium salt of the present invention having a sulfonic acid ester structure, which causes the conjugated acid of the onium anion to have an appropriate acidity, thereby causing efficient proton exchange with the strong acid, and suppressing the diffusion of the generated acid to the unexposed area.

[0318] [Pattern Formation Method]

[0319] When the resist composition of the present invention is used in the manufacture of various integrated circuits, known lithography techniques may be applied. For example, a pattern formation method may include a process of forming a resist film on a substrate using the resist composition described above, a process of exposing the resist film to high-energy rays, and a process of developing the exposed resist film using a developer.

[0320] First, the resist composition of the present invention is applied to a substrate for manufacturing an integrated circuit (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective film, etc.) or a substrate for manufacturing a mask circuit (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 so that the thickness of the coating film is 0.01 to 2 μm. This is pre-baked on a hot plate, preferably at 60 to 150°C for 10 seconds to 30 minutes, more preferably at 80 to 120°C for 30 seconds to 20 minutes, to form a resist film.

[0321] Next, the resist film is exposed using high-energy rays. Examples of the high-energy rays include ultraviolet rays, far-ultraviolet rays, EB (electron beams), EUV (extreme ultraviolet) with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer laser light, gamma rays, synchrotron radiation, etc. When ultraviolet rays, 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 exposure amount is preferably 1 to 200 mJ / cm², either directly or through a mask for forming a desired pattern. 2 Approximately, more preferably 10 to 100 mJ / cm² 2 Irradiate to an extent of this degree. When using EB as the high-energy ray, the exposure amount is preferably 0.1 to 300 μC / cm² 2 The degree, more preferably 0.5 to 200 μC / cm 2Drawing is performed using a mask to form a pattern intended for the purpose, either directly or to the extent. In addition, the resist composition of the present invention is particularly suitable for fine patterning by high-energy rays, specifically KrF excimer laser light, ArF excimer laser light, EB, EUV, X-rays, soft X-rays, γ-rays, and synchrotron radiation, and among these, it is suitable to use KrF excimer laser light, ArF excimer laser light, EB, or EUV with a wavelength of 3 to 15 nm, and is particularly suitable for fine patterning by EB or EUV.

[0322] After exposure, PEB may be performed on a hot plate or in an oven, preferably at 30 to 150°C for 10 seconds to 30 minutes, more preferably at 50 to 120°C for 30 seconds to 20 minutes, or not performed.

[0323] After exposure or after PEB, a desired pattern is formed by developing a resist film exposed by a conventional method such as a dip method, puddle method, or spray method using a developer of an alkaline aqueous solution of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc., in an amount of 0.1 to 10 mass%, preferably 2 to 5 mass%, for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes. In the case of a positive-type resist composition, the portion exposed to light is dissolved in the developer, and the portion not exposed is not dissolved, thereby forming a desired positive-type pattern on the substrate. In the case of a negative-type resist composition, conversely to the case of a positive-type resist composition, the portion exposed to light becomes insoluble in the developer, and the portion not exposed is dissolved.

[0324] By using a positive-type resist composition containing a base polymer containing acid instability groups, a negative-type pattern can also be obtained by organic solvent development. 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, isopentyl lactate, Examples include 2-methyl hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. These organic solvents may be used individually or in combination of two or more types.

[0325] Rinsing is performed when the development is finished. As for the rinsing solution, a solvent that does not dissolve the resist film when mixed with the developer is preferred. Among such solvents, alcohols having 3 to 10 carbon atoms, ether compounds having 8 to 12 carbon atoms, alkanes, alkenes, alkynes having 6 to 12 carbon atoms, and aromatic solvents are preferably used.

[0326] The above alcohols having 3 to 10 carbon atoms include n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, 1-pentanol, 2-pentanol, 3-pentanol, tert-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, Examples include 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol, etc.

[0327] Examples of the above ether compounds having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, di-n-pentyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-pentyl ether, di-n-hexyl ether, etc.

[0328] Examples of the above-mentioned alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane, cyclononane, etc. Examples of the above-mentioned alkenes having 6 to 12 carbon atoms include hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene, cyclooctene, etc. Examples of the above-mentioned alkynes having 6 to 12 carbon atoms include hexine, heptene, octene, etc.

[0329] Examples of the above aromatic solvents include toluene, xylene, ethylbenzene, isopropylbenzene, tert-butylbenzene, mesitylene, etc.

[0330] By rinsing, the breakdown of the resist pattern or the occurrence of defects can be reduced. In addition, rinsing is not strictly necessary, and the amount of solvent used can be reduced by not rinsing.

[0331] The hole pattern or trench pattern after development may be shrunk using thermal flow, RELACS technology, or DSA technology. A shrinking agent is applied onto the hole pattern, and crosslinking of the shrinking agent occurs on the surface of the resist film through the diffusion of an acid catalyst from the resist film during baking, causing the shrinking agent to adhere to the sidewalls of the hole pattern. The baking temperature is preferably 70 to 180°C, more preferably 80 to 170°C, and the baking time is preferably 10 to 300 seconds, and the hole pattern is shrunk by removing the unnecessary shrinking agent.

[0332] Examples

[0333] The present invention will be specifically described below by presenting synthesis examples, examples, and comparative examples, but the present invention is not limited to the following examples. In addition, the apparatus used is as follows.

[0334] ·MALDI TOF-MS: Manufactured by Nippon Denshi Co., Ltd. S3000

[0335] [1] Synthesis of onium salts

[0336] [Example 1-1] Synthesis of SQ-1

[0337]

[0338] (1) Synthesis of intermediate In-1

[0339] Under a nitrogen atmosphere, raw material SM-1 (12.1 g), p-methyl hydroxyanoxate (6.7 g), and 4-dimethylaminopyridine (0.5 g) were dissolved in methylene chloride (100 g). The reaction mixture was cooled in an ice bath, and while maintaining the temperature at 20°C or lower, triethylamine (5.3 g) was added dropwise. After adding the dropwise mixture, the temperature was raised to room temperature and aged for 12 hours. After aging, the reaction mixture was cooled, and water (50 g) was added dropwise to stop the reaction. Subsequently, the reaction mixture was separated and subjected to a normal aqueous work-up. After removing the solvent, the mixture was recrystallized with hexane to obtain 15.6 g of the intermediate In-1 as white crystals (yield 93%).

[0340] (2) Synthesis of intermediate In-2

[0341] Under a nitrogen atmosphere, intermediate In-1 (15.6 g) was dissolved in THF (100 g). The reaction mixture was cooled in an ice bath, and while maintaining the temperature below 20°C, a 25 mass% aqueous sodium hydroxide solution (6.5 g) was added dropwise. After adding, the temperature was raised to room temperature and aged for 12 hours. After aging, the reaction mixture was concentrated, and the precipitated solid was washed with diisopropyl ether. By filtering and drying the solid, 14.6 g of intermediate In-2 was obtained as white crystals (yield 92%).

[0342] (3) Synthesis of Onium Salt SQ-1

[0343] Under a nitrogen atmosphere, intermediate In-2 (6.7 g) and raw material SM-2 (6.5 g) were dissolved in methylene chloride (60 g) and water (30 g) and stirred for 20 minutes. The reaction mixture was separated, the organic layer was separated, and a normal aqueous work-up was performed. After removing the solvent, the onium salt SQ-1 was recrystallized with diisopropyl ether to obtain 7.3 g of white crystals (yield 69%).

[0344] The TOF-MS results of the onium salt SQ-1 are shown below.

[0345] MALDI TOF-MS: POSITIVE M + 263(C 18 H 15 S + (Significant)

[0346] NEGATIVE M - 265(C 22 H 27 O5S - (Significant)

[0347] [Examples 1-2 to 1-9] Synthesis of SQ-2 to SQ-9

[0348] Various onium salts were synthesized through various organic synthesis reactions. The structures of the onium salts used in the resist composition (chemically amplified resist composition) are shown below.

[0349]

[0350] [2] [Synthetic Example] Synthesis of base polymers (P-1 to P-5)

[0351] Each monomer was combined and copolymerized in THF as a solvent, precipitated in methanol, and then isolated and dried after repeated washing with hexane to obtain base polymers (P-1 to P-5) having the compositions shown below. The composition of the obtained base polymers is 1 Mw and Mw / Mn were confirmed by H-NMR and GPC (solvent: THF, standard: polystyrene).

[0352]

[0353]

[0354] [3] [Examples 2-1 to 2-20, Comparative Examples 1-1 to 1-12] Preparation of resist composition

[0355] (1) Preparation of a resist composition

[0356] A resist composition was prepared by dissolving each component in the compositions shown in Tables 1 and 2 and filtering the solution through a 0.2 μm size filter. The resist compositions of Examples 2-1 to 2-18 and Comparative Examples 1-1 to 1-10 are positive types, and the resist compositions of Examples 2-19, 2-20 and Comparative Examples 1-11, 1-12 are negative types.

[0357] Each component in Table 1 is as follows.

[0358] · Organic solvent: PGMEA (propylene glycol monomethyl ether acetate)

[0359] DAA (diacetone alcohol)

[0360] · Mineral generators: PAG-1 to PAG-5

[0361]

[0362] · Blend Quencher: bQ-1, bQ-2

[0363]

[0364] · Comparison Quenchers: cSQ-1 to cSQ-4

[0365]

[0366]

[0367]

[0368] [4] EUV lithography evaluation (1)

[0369] [Examples 3-1 to 3-20, Comparative Examples 2-1 to 2-12]

[0370] Each chemical amplification resist composition (R-1–R-20, CR-1–CR-12) shown in Tables 1 and 2 was spin-coated onto a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 manufactured by Shin-Etsu Chemical Co., Ltd. (silicon content 43 mass%) was formed to a film thickness of 20 nm, and a resist film with a thickness of 50 nm was pre-baked using a hot plate at 100°C for 60 seconds. This was then exposed to an LS pattern with wafer dimensions of 18 nm and a pitch of 36 nm using an ASML EUV scanner NXE3300 (NA 0.33, σ 0.9 / 0.6, dipole illumination), with varying exposure dose and focus (exposure dose / pitch: 1 mJ / cm²). 2 The process was performed while setting the focus pitch to 0.020 μm, and after exposure, PEB was performed for 60 seconds at the temperatures shown in Tables 3 and 4. Subsequently, puddle development was performed for 30 seconds with a 2.38 mass% aqueous TMAH solution, rinsed with a surfactant-containing rinse material, and spin-dried to obtain positive patterns in Examples 3-1 to 3-18 and Comparative Examples 2-1 to 2-10. In addition, negative patterns were obtained in Examples 3-19 and 3-20 and Comparative Examples 2-11 and 2-12.

[0371] The obtained LS patterns were observed using a measuring SEM (CG6300) manufactured by Hitachi High-Tech Corporation, 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 3 and 4.

[0372] [Sensitivity Evaluation]

[0373] Optimal exposure amount E for obtaining an LS pattern with a line width of 18 nm and a pitch of 36 nm op (mJ / cm 2 We calculated ) and used this as the sensitivity. The smaller this value, the higher the sensitivity.

[0374] [EL Evaluation]

[0375] EL (unit: %) was calculated from the exposure amount formed within the range of ±10% (16.2–19.8 nm) of the 18 nm space width in the above LS pattern using the following formula. The higher this value, the better the performance.

[0376] EL(%)=(|E1-E2| / E op )×100

[0377] E1: Optimal exposure amount for imparting an LS pattern with a line width of 16.2 nm and a pitch of 36 nm

[0378] E2: Optimal exposure amount for imparting an LS pattern with a line width of 19.8 nm and a pitch of 36 nm

[0379] E op : Optimal exposure amount for imparting an LS pattern with a line width of 18 nm and a pitch of 36 nm

[0380] [LWR Evaluation]

[0381] E op The LS pattern obtained by investigation was measured at 10 points along the length of the line, and the 3 sets (3σ) of the standard deviation (σ) from the result was calculated as LWR. The smaller this value, the less roughness and the more uniform the line width pattern is obtained.

[0382] [DOF Evaluation]

[0383] As an evaluation of the depth of focus, the focus range formed within ±10% (16.2 to 19.8 nm) of the 18 nm dimension in the above LS pattern was determined. The larger this value, the wider the depth of focus.

[0384] [Assessment of Line Pattern Collapse Limits]

[0385] The line dimensions of each exposure amount at the optimal focus of the above LS pattern were measured at 10 points along the length. The thinnest line dimension obtained without collapse was set as the collapse limit dimension. The smaller this value, the better the collapse limit.

[0386]

[0387]

[0388] From the results shown in Tables 3 and 4, it was found that the chemical amplification resist composition containing the quencher of the present invention exhibits excellent EL, LWR, and DOF with good sensitivity in both positive and negative types. In addition, it was confirmed that the decay limit value is small and that the pattern is resistant to decay even in fine pattern formation.

[0389] [5] EUV lithography evaluation (2)

[0390] [Examples 4-1 to 4-20, Comparative Examples 3-1 to 3-12]

[0391] Each resist composition shown in Tables 1 and 2 was spin-coated onto a Si substrate on which a silicon-containing spin-on hard mask SHB-A940 (silicon content of 43 mass%) manufactured by Shin-Etsu Chemical Co., Ltd. was formed to a film thickness of 20 nm, and a resist film with a film thickness of 60 nm was produced by pre-baking at 100°C for 60 seconds using a hot plate. Next, the resist film was exposed using an ASML-manufactured EUV scanner NXE3400 (NA0.33, σ0.9 / 0.6, quadruple illumination, wafer dimensions with pitch 44 nm, and a mask of a hole pattern with +20% bias), and PEB was performed on a hot plate at the temperatures listed in Tables 5 and 6 for 60 seconds, and development was performed with a 2.38 mass% TMAH aqueous solution for 30 seconds to obtain a hole pattern with dimensions of 22 nm in Examples 4-1 to 4-18 and Comparative Examples 3-1 to 3-10, and a dot pattern with dimensions of 22 nm in Examples 4-19, 4-20 and Comparative Examples 3-11, 3-12.

[0392] Using a measuring SEM (CG6300) manufactured by Hitachi High-Tech Corporation, the exposure amount at which a hole or dot dimension is formed to 22 nm was measured and this was set as the sensitivity. Additionally, the dimensions of 50 holes or dots at this time were measured, and three sets (3σ) of the standard deviation (σ) calculated from the results were set as the CDU. The results are shown in Tables 5 and 6.

[0393]

[0394]

[0395] From the results shown in Tables 5 and 6, it was confirmed that the chemical amplification resist composition containing the quencher of the present invention has good sensitivity in both positive and negative types and excellent CDU.

[0396] This specification includes the following aspects.

[0397] [1]: An onium salt characterized by being represented by the following general formula (1).

[0398]

[0399] (In the expression, n1 is an integer of 0 or 1. n2 is an integer of 0 to 3. R 1a is a hydrocarbyl group having 1 to 20 carbon atoms that may contain a halogen atom or a heteroatom. n3 is an integer from 0 to 3. R 1b is a hydrocarbyl group having 1 to 36 carbon atoms that may contain heteroatoms. n4 is an integer of 1 or 2. Z + represents an onium cation.)

[0400] [2]: An onium salt of [1] characterized in that the above general formula (1) is represented by the following formula (1-A).

[0401]

[0402] (during food, R 1a , R 1b , n1, n3, n4 and Z +is as above.)

[0403] [3]: An onium salt of [1] or [2] characterized in that the above general formula (1) is represented by the following general formula (1-B).

[0404]

[0405] (during food, R 1a , R 1b , n3, and Z + is as above.)

[0406] [4]: Additionally, Z in the above general formula (1) + One of the onium salts [1] to [3], characterized by being an onium cation represented by any one of the following general formulas (Cation-1) to (Cation-3).

[0407]

[0408] (Among equations (Cation-1) to (Cation-3), R 11' ~R 19' Each is independently a straight, branched, or cyclic hydrocarbyl group having 1 to 30 carbon atoms, which may contain heteroatoms and may be saturated or unsaturated.

[0409] [5]: An acid diffusion control agent characterized by comprising any one of [1] to [4] onium salts.

[0410] [6]: A resist composition characterized by including an acid diffusion control agent of [5].

[0411] [7]: A resist composition of [6] characterized by further including an acid-generating agent that generates acid.

[0412] [8]: A resist composition of [7] characterized in that the above acid generating agent generates sulfonic acid, imidic acid or methic acid.

[0413] [9]: A resist composition of any one of [6] to [8] characterized by further including an organic solvent.

[0414]

[10] : A resist composition of any one of [6] to [9] characterized by further including a base polymer.

[0415]

[11] : A resist composition of

[10] characterized in that the base polymer comprises repeating units represented by the following general formula (a1) and / or repeating units represented by the following general formula (a2).

[0416]

[0417] (during food, R A Each is independently a hydrogen atom or a methyl group. Y 1 is a linker having 1 to 12 carbon atoms comprising at least one selected from a single bond, a phenylene group or a naphthylene group, or an ester bond and a lactone ring. 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond, or an ester bond. R 11 and R 12 are each independently mountain instability phases. R 13 It is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 14 is a single bond or an alkandyl group having 1 to 6 carbon atoms, and some of its carbon atoms may be substituted by ether or ester bonds. a is 1 or 2. b is an integer from 0 to 4, provided that 1 ≤ a + b ≤ 5.)

[0418]

[12] : The resist composition of

[11] , characterized in that the resist composition is a chemically amplified positive type resist composition.

[0419]

[13] : A resist composition of

[10] characterized in that the base polymer does not contain acid unstable groups.

[0420]

[14] : The resist composition of

[13] , characterized in that the resist composition is a chemically amplified negative type resist composition.

[0421]

[15] : A resist composition of any one of

[10] to

[14] , characterized in that the base polymer further comprises at least one type selected from repeating units represented by the following general formulas (f1) to (f3).

[0422]

[0423] (during food, R A are each independently a hydrogen atom or a methyl group. Z 1 is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, an ester bond, or a group having 7 to 18 carbon atoms obtained by a combination thereof, or -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -is. Z 11 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by a combination thereof, and may include a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -OC(=O)- is. Z 31 is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by a combination thereof, and may include a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine atom. Z 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethandiyl group, or a carbonyl group. Z 5is a single bond, methylene group, ethylene group, phenylene group, fluorinated phenylene group, phenylene group substituted with a trifluoromethyl group, -OZ 51 -, -C(=O)-OZ 51 - or -C(=O)-NH-Z 51 -is. Z 51 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may also be a combination thereof, and may include a carbonyl group, an ester bond, an ether bond, a halogen atom, and / or a hydroxyl group. 21 ~R 28 is a hydrocarbyl group having 1 to 20 carbon atoms, which may each independently contain a halogen atom or a heteroatom. Also, R 23 and R 24 or R 26 and R 27 They may be bonded to each other and form a ring together with the sulfur atoms to which they bond. M - is a non-nucleated counterion.)

[0424]

[16] : A resist composition of any one of [6] to

[15] characterized by further including a surfactant.

[0425]

[17] : A method for forming a pattern characterized by including a process of forming a resist film on a substrate using any one of [6] to

[16] , a process of exposing the resist film to high energy rays, and a process of developing the exposed resist film using a developer.

[0426]

[18] : A pattern forming method of

[17] characterized by using KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet light with a wavelength of 3 to 15 nm as the high-energy line.

[0427] Meanwhile, the present invention is not limited to the above embodiments. The above embodiments are examples, and any configuration substantially identical to the technical concept described in the claims of the present invention and exhibiting the same functional effect is included within the technical scope of the present invention.

Claims

Claim 1 Onium salts characterized by being represented by the following general formula (1) (except those represented by the following (1)' formula): (In the expression, n1 is an integer of 0 or 1. n2 is an integer of 0 to 3. R 1a is a hydrocarbyl group having 1 to 20 carbon atoms that may contain a halogen atom or a heteroatom. n3 is 0. R 1b is a hydrocarbyl group having 1 to 24 carbon atoms that may contain a halogen atom. n4 is an integer of 1 or 2. Z + represents an onium cation represented by any one of the following general formulas (Cation-1) to (Cation-3). (Among equations (Cation-1) to (Cation-3), R 11' ~R 19' Each is independently a straight, branched, or cyclic hydrocarbyl group having 1 to 30 carbon atoms, which may contain heteroatoms and may be saturated or unsaturated. (In the formula, Bu represents a butyl group.) Claim 2 Onium salt according to claim 1, characterized in that the above general formula (1) is represented by the following formula (1-A): (during food, R 1a , R 1b , n1, n3, n4 and Z + is as above.) Claim 3 In paragraph 2, an onium salt characterized in that the above general formula (1) is represented by the following general formula (1-B): (during food, R 1a , R 1b , n3, and Z + is as above.) Claim 4 An acid diffusion control agent characterized by comprising an onium salt described in any one of claims 1 to 3. Claim 5 A resist composition characterized by including the acid diffusion control agent described in paragraph 4. Claim 6 A resist composition characterized by further including an acid-generating agent that generates acid in claim 5. Claim 7 A resist composition according to claim 6, characterized in that the acid generating agent generates sulfonic acid, imidic acid, or methic acid. Claim 8 A resist composition characterized by further including an organic solvent in claim 5. Claim 9 A resist composition characterized by further including a base polymer in claim 5. Claim 10 A resist composition according to claim 9, characterized in that the base polymer comprises either or both of a repeating unit represented by the following general formula (a1) and a repeating unit represented by the following general formula (a2): (during food, R A Each is independently a hydrogen atom or a methyl group. Y 1 is a linker having 1 to 12 carbon atoms comprising one or more selected from single bonds, phenylene groups or naphthylene groups, or ester bonds and lactone rings. 2 is a single bond or an ester bond. Y 3 is a single bond, an ether bond, or an ester bond. R 11 and R 12 Each is an independent acid instability group. The above acid instability groups are represented by the following general formulas (AL-1) to (AL-3). (In the equation, dashed lines are connection points. R L1 and R L2 is a hydrocarbyl group having 1 to 40 carbon atoms that may each independently contain a heteroatom, c is an integer from 0 to 10, and R L3 and R L4 is a hydrocarbyl group having 1 to 20 carbon atoms that may each independently contain a hydrogen atom or a heteroatom, and R L2 , R L3 and R L4 Any two of them may combine with each other to form a ring having 3 to 20 carbon atoms together with the carbon atom to which they bond, or with a carbon atom and an oxygen atom. R L5 , R L6 and R L7 Each is independently a hydrocarbyl group having 1 to 20 carbon atoms, which may contain heteroatoms, and R L5 , R L6 and R L7 Any two of them may bond with each other to form a ring having 3 to 20 carbon atoms together with the carbon atoms to which they bond.)R 13 It is a fluorine atom, a trifluoromethyl group, a cyano group, or a saturated hydrocarbyl group having 1 to 6 carbon atoms. R 14 is a single bond or an alkandyl group having 1 to 6 carbon atoms, and some of its carbon atoms may be substituted by ether or ester bonds. a is 1 or 2. b is an integer from 0 to 4, provided that 1 ≤ a + b ≤ 5.) Claim 11 A resist composition according to claim 10, characterized in that the resist composition is a chemically amplified positive type resist composition. Claim 12 A resist composition according to claim 9, characterized in that the base polymer does not contain acid unstable groups. Claim 13 A resist composition according to claim 12, characterized in that the resist composition is a chemically amplified negative type resist composition. Claim 14 A resist composition according to claim 9, characterized in that the base polymer further comprises one or more types selected from repeating units represented by the following general formulas (f1) to (f3): (during food, R A are each independently a hydrogen atom or a methyl group. Z 1 is a single bond, an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, an ester bond, or a group having 7 to 18 carbon atoms obtained by a combination thereof, or -OZ 11 -, -C(=O)-OZ 11 - or -C(=O)-NH-Z 11 -is. Z 11 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a naphthylene group, or a group having 7 to 18 carbon atoms obtained by a combination thereof, and may include a carbonyl group, an ester bond, an ether bond, or a hydroxyl group. Z 2 is a single bond or an ester bond. Z 3 is a single bond, -Z 31 -C(=O)-O-, -Z 31 -O- or -Z 31 -OC(=O)- is. Z 31 is a hydrocarbylene group having 1 to 12 carbon atoms, a phenylene group, or a group having 7 to 18 carbon atoms obtained by a combination thereof, and may include a carbonyl group, an ester bond, an ether bond, an iodine atom, or a bromine atom. Z 4 is a methylene group, a 2,2,2-trifluoro-1,1-ethandiyl group, or a carbonyl group. Z 5 is a single bond, methylene group, ethylene group, phenylene group, fluorinated phenylene group, phenylene group substituted with a trifluoromethyl group, -OZ 51 -, -C(=O)-OZ 51 - or -C(=O)-NH-Z 51 -is. Z 51 is an aliphatic hydrocarbylene group having 1 to 6 carbon atoms, a phenylene group, a fluorinated phenylene group, or a phenylene group substituted with a trifluoromethyl group, and may also be a combination thereof, and may include any or both of a carbonyl group, an ester bond, an ether bond, a halogen atom, and a hydroxyl group. 21 ~R 28 is a hydrocarbyl group having 1 to 20 carbon atoms, which may each independently contain a halogen atom or a heteroatom. Also, R 23 and R 24 or R 26 and R 27 They may be bonded to each other and form a ring together with the sulfur atoms to which they bond. M - is a non-nucleated counterion.) Claim 15 A resist composition characterized by further including a surfactant in claim 5. Claim 16 A pattern forming method characterized by comprising: a process of forming a resist film on a substrate using a resist composition described in paragraph 5; a process of exposing the resist film to high-energy rays; and a process of developing the exposed resist film using a developer. Claim 17 A pattern forming method according to claim 16, characterized by using KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet light with a wavelength of 3 to 15 nm as the high-energy line. Claim 18 delete

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