Chemically amplified resist composition and pattern formation method

Abstract

The present invention provides a chemically amplified resist composition characterized by containing (A) a photoacid generator, (B) a base polymer having an acid-unstable group, and (C) an organic solvent, and further containing (D) a fluorine atom-containing polymer having a repeating unit having a structure represented by the following formula (d0) and a base-dissociable group. This provides a chemically amplified resist composition and a pattern formation method that have higher sensitivity than conventional resist compositions, good lithography performance such as CDU and LWR, and good water repellency and development defect suppression ability. [C181] TIFF0007927201000185.tif2039 (In this formula, X is a halogen atom other than a fluorine atom.)

Description

[Technical Field]

[0001] The present invention relates to a fluorine atom-containing polymer, a chemically amplified resist composition, and a pattern forming method. [Background technology]

[0002] In recent years, with the increasing integration and speed of LSIs, the formation of fine patterns has become necessary, and chemically amplified resist compositions using acid as a catalyst are used for pattern processing of 0.2 μm or less. High-energy beams such as ultraviolet light, far ultraviolet light, and electron beams are used as exposure sources in this process. As one of the most advanced miniaturization technologies, mass production is being carried out using ArF immersion lithography, in which a liquid such as water is inserted between the projection lens and the substrate for exposure, and research is underway on multiple exposure in ArF lithography and extreme ultraviolet (EUV) lithography with a wavelength of 13.5 nm.

[0003] In particular, in ArF immersion lithography, leaching can occur when water-soluble components in the resist film (especially acids and basic compounds generated during exposure) penetrate the immersion water. In this case, the dimensions and shape of the pattern may change, raising concerns about bridge defects due to decreased surface solubility, or conversely, twisting and collapsing defects due to increased surface solubility. It has also been pointed out that small amounts of water droplets remaining after scanning may seep into the resist film and induce defects. Non-patent document 1 proposed a method (topcoat process) in ArF immersion lithography to suppress the elution of resist components and the penetration of water into the resist film by providing a protective film between the resist film and the water.

[0004] On the other hand, the topcoat process requires a protective film removal step after resist exposure. From a cost / process perspective, a topcoat-less process has been developed that suppresses the elution of resist components and the penetration of water into the resist film without using protective film materials. Patent documents 1 and 2 describe adding an alkali-soluble hydrophobic polymer compound to the resist material and localizing the hydrophobic compound on the resist surface during resist film formation. Therefore, it is expected to have the same effect as the topcoat process, and is also cost-effective as it eliminates the need for processes related to the formation and removal of the protective film.

[0005] In both topcoat and topcoat-less processes, ArF immersion lithography has required scan speeds of around 300-700 mm / s to increase throughput. When performing such high-speed scans, if the water repellency of the resist film or protective film is insufficient, water droplets may remain on the film surface after scanning, potentially inducing defects. To eliminate such defects, it is necessary to improve the water repellency and water-sliding properties (especially the receding contact angle) of the coated film.

[0006] Non-patent document 2 mentions a copolymer of a monomer having a trifluoromethyl group and a norbornene derivative as a material with excellent water-repellent / hydrophobic properties. Furthermore, non-patent document 3 reports a polymer composed of monomers having hexafluoroalcohol units, which exhibits even higher hydrophobic performance by protecting the hydroxyl group with an acid-unstable group.

[0007] As with the resins mentioned above, introducing fluorine into the polymer backbone dramatically improves water repellency and hydrophobicity, but excessive introduction induces a new type of defect called a Blob defect. This defect occurs during spin-drying after development and is more likely to occur when the surface contact angle after development is high. Therefore, introducing highly hydrophilic substituents (e.g., carboxyl groups or sulfo groups) into the resin to lower the surface contact angle after development can suppress Blob defects, but these groups reduce the water repellency and hydrophobicity of the resin, making them unsuitable for high-speed scanning as described above. Consequently, there is a need for the development of materials that can suppress Blob defects while maintaining high water repellency and hydrophobicity during immersion exposure. Patent document 3 reports on polymers having fluorinated monomers into which alkaline hydrolyzable groups have been introduced, and these polymers exhibit increased solubility in alkaline developers due to the action of alkaline developers. That is, they have high water repellency and hydrophobicity during exposure, and the hydrophilic groups are exposed during development, improving the alkaline dissolution rate. This function can be used to modify the surface of not only ArF immersion lithography materials but also EUV exposure materials.

[0008] As described above, the materials have greatly contributed to the advancements in ArF immersion lithography and EUV lithography. The polymers used in these topcoat and topcoat-less processes must contain fluorine atoms. In addition, in ArF immersion lithography, onium salts containing perfluoroalkanesulfonic acid anions are commonly used as photoacid generators. These fluorine-containing substances (especially PFAS materials) do not have degradable groups such as ester structures and hardly decompose in nature, making them persistent compounds that remain in the environment for long periods. Furthermore, because they are water-soluble, they diffuse widely through water systems, resulting in a significant environmental burden and becoming a problem in modern society.

[0009] In recent years, examples have been reported of using compounds containing fluorine atoms but not classified as PFAS as substitutes for resist materials, as well as examples of using compounds that do not contain fluorine atoms. Patent documents 4, 5, and 6 report examples of using CF2H groups as PFAS substitutes, and examples of introducing fluorinated unsaturated bonds. Patent document 7 also reports an example of using CF2Cl groups as PFAS substitutes. However, further improvements in water repellency and development defect suppression are required.

[0010] Thus, conventional technologies have problems in that they do not provide resist compositions or pattern formation methods that simultaneously satisfy lithography performance such as sensitivity, CDU, LWR, water repellency, and development defect suppression ability in the mass production of devices by ArF immersion lithography, while also having a low environmental impact. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2006-48029 [Patent Document 2] Japanese Patent Publication No. 2006-309245 [Patent Document 3] Patent No. 5375811 [Patent Document 4] International Patent Publication No. 2025-134675 [Patent Document 5] International Patent Publication No. 2025-134677 [Patent Document 6] International Patent Publication No. 2025-134678 [Patent Document 7] International Patent Publication No. 2024-248135 [Non-patent literature]

[0012] [Non-Patent Document 1] 2nd Immersion Work Shop: Resist and Cover Material Investigation for Immersion Lithography (2003) [Non-Patent Document 2] Proc. SPIE. Vol. 4690, p18 (2002) [Non-Patent Document 3] Proc. SPIE. Vol. 6519, p651905 (2007) [Overview of the Initiative] [Problems that the invention aims to solve]

[0013] The present invention has been made in view of the above circumstances, and aims to provide a chemically amplified resist composition and a pattern formation method that have higher sensitivity than conventional resist compositions, good lithography performance such as CDU and LWR, and good water repellency and development defect suppression ability. [Means for solving the problem]

[0014] In order to solve the above problems, the present invention provides: The present invention provides a chemically amplified resist composition comprising (A) a photoacid generator, (B) a base polymer having an acid-unstable group, and (C) an organic solvent, and further comprising (D) a fluorine atom-containing polymer having a repeating unit having a structure represented by the following formula (d0) and a base-dissociable group. [ka] (In the formula, X is a halogen atom other than a fluorine atom.)

[0015] Such a chemically amplified resist composition would have higher sensitivity than conventional resist compositions, good lithography performance such as CDU and LWR, and good water repellency and development defect suppression capabilities.

[0016] Further, the (D) fluorine atom-containing polymer may include a repeating unit represented by the following formula (D1), and preferably includes at least one of a repeating unit represented by the following formula (D2) and a repeating unit represented by the following formula (D3).

Chemical Formula

[0017] Such (D) fluorine atom-containing polymers exhibit even better water repellency and development defect suppression capabilities.

[0018] In this case, it is preferable that the (D) fluorine atom-containing polymer contains repeating units represented by the following formula (D4). [ka] (In the formula, R B This is the same as described above. R 26 R is a linear, branched, or cyclic hydrocarbylene group having 1 to 20 carbon atoms, which may contain single bonds, ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or urea bonds. 27 Each of these groups is independently a hydrogen atom, a C1-C12 hydrocarbyl group, a C1-C12 hydrocarbyloxy group, a C2-C12 hydrocarbyloxycarbonyl group, a C2-C12 hydrocarbylcarbonyloxy group, a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, or a nitro group, and may contain heteroatoms, acid-unstable groups, or base-unstable groups. o is either 0 or 1. When o is 0, m and n are independent integers between 0 and 5, and 0 ≤ m + n ≤ 5. When o is 1, m and n are independent integers between 0 and 7, and 0 ≤ m + n ≤ 7.

[0019] (D) Fluorine atom-containing polymers can be made even more hydrophobic by including such repeating units.

[0020] Furthermore, it is preferable that the repeating unit (D2) is represented by the following formula (D2-1). [ka] (In the formula, R B, R 25 (X and k are the same as above.)

[0021] The repeating unit (D2) is particularly suited to this structure.

[0022] In this case, it is preferable that the (D) fluorine atom-containing polymer includes a repeating unit represented by formula (D2-1) and a repeating unit represented by the following formula (D4-1). [ka] (In the formula, R B This is the same as above. R 26 R is a linear, branched, or cyclic hydrocarbylene group having 1 to 20 carbon atoms, which may contain single bonds, ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or urea bonds. 27 Each of these groups is independently a hydrogen atom, a C1-C12 hydrocarbyl group, a C1-C12 hydrocarbyloxy group, a C2-C12 hydrocarbyloxycarbonyl group, a C2-C12 hydrocarbylcarbonyloxy group, a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, or a nitro group, and may contain heteroatoms, acid-unstable groups, or base-unstable groups. m is an integer of 4 or 5, where n=1 when m=4 and n=0 when m=5.

[0023] In the present invention, such (D) fluorine atom-containing polymers can be used more preferably.

[0024] Furthermore, it is preferable that the content of the (D) fluorine atom-containing polymer is 0.1 to 20 parts by mass with respect to 80 parts by mass of the (B) base polymer.

[0025] (D) The effects of the present invention can be more fully realized if the content of the fluorine atom-containing polymer is within this range.

[0026] Furthermore, it is preferable that the (B) base polymer contains repeating units having an acid-unstable group represented by the following formula (B1). [ka] (In the formula, R A R is a hydrogen atom or a methyl group. AL It is an acid-unstable group.

[0027] In this case, the (B) base polymer may include at least one selected from the repeating units represented by the following formula (B2), the repeating unit represented by the following formula (B3), and the repeating unit represented by the following formula (B4). [ka] (In the formula, R A R is a hydrogen atom or a methyl group. 11 and R 12 Each of these is independently either a hydrogen atom or a hydroxyl group. 13 R is a substituent having a lactone structure or a substituent having a sultone structure. 14 (This is a hydrogen atom, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or a monovalent fluoroalcohol-containing substituent having 1 to 15 carbon atoms.)

[0028] In the present invention, such (B)-based polymers can be suitably used.

[0029] Furthermore, it is preferable that the photoacid generator (A) does not contain "fully fluorinated methyl groups" or "fully fluorinated methylene groups".

[0030] In this case, it is preferable that the photoacid generator (A) is represented by the following formula (a). [ka] [ka] [ka] [In the formula, R is a hydrocarbyl group having 1 to 50 carbon atoms, which may be substituted with a heteroatom, and L is a divalent linking group represented by formula (a1) or (a2). In equation (a1), m1 is an integer between 1 and 4. 1 and R 2 Each of these is independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxyl group, an alkoxy group, an alkylthio group, an amino group, a mercapto group, a pentafluorosulfanyl group, or a C1-C20 hydrocarbyl group, hydrocarbyloxy group, or hydrocarbylthio group, which may contain a heteroatom, and at least one of them is an electron-withdrawing group. In equation (a2), m2 is an integer between 0 and 1. m3 is between 0 and 4 when m2 is 0, and between 0 and 6 when m2 is 1. m4 is between 0 and 4 when m2 is 0, and between 0 and 6 when m2 is 1. However, when m2 is 0, 1 ≤ m3 + m4 ≤ 4, and when m2 is 1, 1 ≤ m3 + m4 ≤ 6. R f R is a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms, or a pentafluorosulfanil group. When there are multiple m3s, each R f These may be identical or different from each other. 3 This is a C1-C20 hydrocarbyl group, hydrocarbyloxy group, or hydrocarbylthio group, which may contain halogen atoms other than fluorine atoms, cyano groups, nitro groups, hydroxyl groups, alkoxy groups, alkylthio groups, amino groups, mercapto groups, or heteroatoms. However, when m3 is 0, R 3 At least one of them is an electron-withdrawing group. In formulas (a1) and (a2), * indicates the binding site with R, and ** indicates the binding site with the sulfonate anion. Z + This is a sulfonium cation represented by the following formula (Z-1) or an iodonium cation represented by the following formula (Z-2). [ka] (In the formula, R ct1 ~R ct5 Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain a halogen atom or a heteroatom. ct1 and R ct2 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded.

[0031] In the present invention, such (A) photoacid generators can be suitably used.

[0032] The chemically amplified resist composition of the present invention may further contain a surfactant.

[0033] The chemically amplified resist composition of the present invention may further include a quencher.

[0034] The chemically amplified resist composition of the present invention may optionally contain various other components.

[0035] The present invention also provides a pattern formation method comprising the steps of: forming a resist film on a substrate using the above-mentioned chemically amplified resist composition; exposing the resist film with high-energy rays; and developing the exposed resist film using a developer.

[0036] The present invention provides a pattern formation method that exhibits higher sensitivity than conventional resist compositions, good lithography performance such as CDU and LWR, and good water repellency and development defect suppression capabilities.

[0037] Furthermore, it is preferable that the high-energy beam is KrF excimer laser light, ArF excimer laser light, an electron beam, or extreme ultraviolet light with a wavelength of 3 to 15 nm.

[0038] The chemically amplified resist composition of the present invention is preferably subjected to exposure with such high-energy rays.

[0039] Furthermore, in the pattern formation method of the present invention, it is preferable to insert water between the projection lens and the resist film during the exposure step and to expose the film with high-energy rays through a photomask.

[0040] The chemically amplified resist composition and pattern formation method of the present invention can be suitably used in immersion lithography.

[0041] Furthermore, the present invention provides a fluorine atom-containing polymer that includes repeating units having a structure represented by the following formula (d0) and a base-dissociable group. [ka] (In the formula, X is a halogen atom other than a fluorine atom.)

[0042] By using such a fluorine atom-containing polymer as a surfactant, a chemically amplified resist composition is obtained that exhibits higher sensitivity than conventional resist compositions, good lithography performance such as CDU and LWR, and good water repellency and development defect suppression ability.

[0043] Furthermore, the fluorine atom-containing polymer of the present invention may contain repeating units represented by the following formula (D1), and preferably contains at least one of the repeating units represented by the following formula (D2) and the following formula (D3). [ka] (In the formula, R B This is either a hydrogen atom or a methyl group. L is a C1-C10 hydrocarbylene group which may contain a single bond, a carbonyl group, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonamide bond, a carbonate bond, a carbamate bond, or a carbonyl group, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonamide bond, a carbonate bond, or a carbamate bond. 21 and R 22Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. 23 This is a 1-20 carbon dioxide hydrocarbylene group which may contain single bonds or linear, branched, or cyclic heteroatoms. 23k This is a (k+1) valent organic group having 1 to 20 carbon atoms, which may contain single bonds or linear, branched, or cyclic heteroatoms. 24 This includes a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, and an acyl group having 2 to 15 carbon atoms, and the hydrocarbyl group and acyl group may contain heteroatoms or acid-unstable groups. 24 When the group is a hydrocarbyl group, some of these -CH2- groups may be substituted with ether bonds or carbonyl groups. 25 This is a single-bonded, linear, or branched hydrocarbylene group having 1 to 5 carbon atoms. 25k A (k+1) valence organic group is a single-bonded, linear, or branched organic group with 1 to 5 carbon atoms. j is an integer between 1 and 2. k is an integer between 1 and 3. X is the same as described above.

[0044] Such fluorine atom-containing polymers exhibit even better water repellency and development defect suppression capabilities.

[0045] In this case, it is preferable that the repeating unit is represented by the following formula (D4). [ka] (In the formula, R B This is the same as described above. R 26 R is a linear, branched, or cyclic hydrocarbylene group having 1 to 20 carbon atoms, which may contain single bonds, ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or urea bonds. 27Each of these groups is independently a hydrogen atom, a C1-C12 hydrocarbyl group, a C1-C12 hydrocarbyloxy group, a C2-C12 hydrocarbyloxycarbonyl group, a C2-C12 hydrocarbylcarbonyloxy group, a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, or a nitro group, and may contain heteroatoms, acid-unstable groups, or base-unstable groups. o is either 0 or 1. When o is 0, m and n are independent integers between 0 and 5, and 0 ≤ m + n ≤ 5. When o is 1, m and n are independent integers between 0 and 7, and 0 ≤ m + n ≤ 7.

[0046] Fluorine atom-containing polymers can become even more hydrophobic by including such repeating units.

[0047] Furthermore, it is preferable that the repeating unit (D2) is represented by the following formula (D2-1). [ka] (In the formula, R B , R 25 (X and k are the same as above.)

[0048] The repeating unit (D2) is particularly suited to this structure.

[0049] In this case, the fluorine atom-containing polymer preferably includes a repeating unit represented by formula (D2-1) and a repeating unit represented by the following formula (D4-1). [ka] (In the formula, R B This is the same as above. R 26R is a linear, branched, or cyclic hydrocarbylene group having 1 to 20 carbon atoms, which may contain single bonds, ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or urea bonds. 27 Each of these groups is independently a hydrogen atom, a C1-C12 hydrocarbyl group, a C1-C12 hydrocarbyloxy group, a C2-C12 hydrocarbyloxycarbonyl group, a C2-C12 hydrocarbylcarbonyloxy group, a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, or a nitro group, and may contain heteroatoms, acid-unstable groups, or base-unstable groups. m is an integer of 4 or 5, where n=1 when m=4 and n=0 when m=5.

[0050] In the present invention, such fluorine atom-containing polymers can be used more favorably. [Effects of the Invention]

[0051] By using the chemically amplified resist composition of the present invention, it is possible to form patterns that exhibit high sensitivity, improved lithography performance such as CDU and LWR, and improved water repellency and development defect suppression. Furthermore, the chemically amplified resist composition of the present invention is suitable as a material for ArF immersion lithography and is useful in both positive pattern formation by alkaline development and negative pattern formation by organic solvent development. The pattern formation method of the present invention can be applied to the mass production of 5nm node devices, which have fine patterns corresponding to the high integration and high speed of LSIs, and further to the mass production of next-generation 3nm node and subsequent-generation 2nm node devices. It is also useful because it is a PFAS-free compound, resulting in a low environmental impact during mass production. [Modes for carrying out the invention]

[0052] As described above, there has been a need for the development of a chemically amplified resist composition and pattern formation method that exhibits higher sensitivity than conventional resist compositions, good lithography performance such as CDU and LWR, and good water repellency and development defect suppression capabilities.

[0053] As a result of diligent research to achieve the above objective, the present inventors have discovered that by using a resist composition containing a fluorine atom-containing polymer having a difluorohalogen unit having a chlorine atom, a bromine atom, or an iodine atom, a resist pattern can be obtained that is highly sensitive, has good lithography performance such as CDU and LWR, and has excellent water repellency and development defect suppression ability, thus completing the present invention.

[0054] In other words, the present invention is a chemically amplified resist composition containing (A) a photoacid generator, (B) a base polymer having an acid-unstable group, and (C) an organic solvent, and further containing (D) a fluorine atom-containing polymer having a repeating unit having a structure represented by the following formula (d0) and a base-dissociable group. [ka] (In the formula, X is a halogen atom other than a fluorine atom.)

[0055] The present invention will be described in detail below. In the following description, depending on the structure represented by the chemical formula, an asymmetric carbon may be present, and enantiomers or diastereomers may exist. In such cases, one formula will represent all of these isomers. These isomers may be used individually or as a mixture of two or more.

[0056] [Chemically amplified resist composition] The chemically amplified resist composition of the present invention comprises (A) a photoacid generator, (B) a base polymer, (C) an organic solvent, and (D) a fluorine atom-containing polymer having a repeating unit with a structure represented by formula (d0) and a base-dissociable group.

[0057] [(D) Fluorine atom-containing polymer] (D) The fluorine atom-containing polymer contains repeating units having a structure represented by the following formula (d0) and a base-dissociable group. (D) The fluorine atom-containing polymer is a different polymer from the base polymer of component (B) described later. [ka] (In the formula, X is a halogen atom other than a fluorine atom.)

[0058] The structure represented by formula (d0) is, for example, a difluorochloromethyl group, a difluorobromomethyl group, and a difluoroiodomethyl group.

[0059] There are no particular restrictions on the types of base-dissociable groups, as long as they dissociate in the presence of a base. Examples include ester bonds (―O―C(=O)-) and reverse ester bonds (―C(=O)-O-). The mechanism by which these groups act as base-dissociable groups will be described later.

[0060] Furthermore, the fluorine atom-containing polymer of the present invention may contain repeating units represented by the following formula (D1), and preferably contains at least one of the repeating units represented by the following formula (D2) and the following formula (D3). Here, the repeating units represented by the following formula (D2) and the following formula (D3) correspond to repeating units having the structure represented by the above formula (d0) and a base-dissociable group. The repeating unit represented by the following formula (D1) is a repeating unit that the fluorine atom-containing polymer may optionally contain. [ka]

[0061] In equations (D1) to (D3), R BL is a hydrogen atom or a methyl group. L is a C1-C10 hydrocarbylene group which may contain a single bond, a carbonyl group, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonamide bond, a carbonate bond, a carbamate bond, or a carbonyl group, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonamide bond, a carbonate bond, or a carbamate bond. 21 and R 22 Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. 23 This is a 1-20 carbon dioxide hydrocarbylene group which may contain single bonds or linear, branched, or cyclic heteroatoms. 23k This is a (k+1) valent organic group having 1 to 20 carbon atoms, which may contain single bonds or linear, branched, or cyclic heteroatoms. 24 This includes a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, and an acyl group having 2 to 15 carbon atoms, and the hydrocarbyl group and acyl group may contain heteroatoms or acid-unstable groups. 24 When the group is a hydrocarbyl group, some of these -CH2- groups may be substituted with ether bonds or carbonyl groups. 25 This is a single-bonded, linear, or branched hydrocarbylene group having 1 to 5 carbon atoms. 25k is a (k+1) valence organic group having 1 to 5 carbon atoms, either single-bonded, linear, or branched. j is an integer between 1 and 2. k is an integer between 1 and 3. X is the same as described above.

[0062] R 21 and R 22The C1-C10 hydrocarbyl group represented by is preferably a saturated hydrocarbyl group and may be linear, branched, or cyclic. Specific examples include C1-C10 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, and n-decyl groups; and C3-C10 cyclic saturated hydrocarbyl groups such as cyclopentyl, cyclohexyl, adamantyl, and norbornyl groups. Of these, those with C1-C6 are preferred.

[0063] R 23 The hydrocarbylene group represented by has 1 to 20 carbon atoms, preferably 1 to 5 carbon atoms, is preferably a saturated hydrocarbylene group and may be linear, branched, or cyclic. Specific examples include methylene group, ethylene group, trimethylene group, propylene group, tetramethylene group, pentamethylene group, etc. Also, R 23 There are no particular restrictions on the heteroatoms that may be included in the hydrocarbylene group, but examples include oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc.

[0064] R 24 The C1-C15 hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include saturated hydrocarbyl groups, alkenyl groups, alkynyl groups, and other aliphatic unsaturated hydrocarbyl groups, but saturated hydrocarbyl groups are preferred. The saturated hydrocarbyl group is R 21 and R 22 In addition to those mentioned above, specific examples of the 1-10 carbon dioxide hydrocarbyl group represented by include n-undecyl, n-dodecyl, tridecyl, tetradecyl, and pentadecyl groups. Furthermore, some of the -CH2- groups of the hydrocarbyl group may be substituted with ether bonds or carbonyl groups. 24There are no particular restrictions on the heteroatoms that may be included in the hydrocarbyl group, but examples include oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc.

[0065] R 24 When the group is acid-unstable, specific examples include tertiary hydrocarbyl groups having 4 to 20 carbon atoms, preferably 4 to 15; trihydrocarbylsilyl groups in which each hydrocarbyl group has 1 to 6 carbon atoms; carbonyl groups; and hydrocarbyl groups having 4 to 20 carbon atoms that include an ether bond or an ester bond.

[0066] (D) The fluorine atom-containing polymer has a structure represented by the following formula (d0) in the repeating units represented by the general formulas (D1), (D2), and (D3), and therefore the polymer itself functions as a surfactant. That is, when this polymer is added to a resist material, the (D) fluorine atom-containing polymer is localized and distributed on the surface of the resist film at the same time as film formation. [ka] (In the formula, X is a halogen atom other than a fluorine atom.)

[0067] Generally, fluorine atom-containing polymers exhibit excellent water-repellent and hydrophobic properties. Therefore, applying a composition containing a fluorine atom-containing polymer to the surface after resist film formation functions as a useful protective film in the topcoat process. Furthermore, when used as a resist additive, it simultaneously forms a resist film surface with excellent water-repellent and hydrophobic properties while simultaneously forming the resist material, thus functioning as a useful protective film in topcoat-less processes.

[0068] This paper describes the required performance characteristics of fluorine atom-containing polymers used in topcoat-less processes and the units necessary to meet those characteristics.

[0069] (1) Water repellency, liquid repellency To provide a barrier function that prevents the penetration of water and onium salts and amine compounds contained in the resist composition, water-repellent and liquid-repellent properties are necessary, and the presence of fluorine-containing hydrocarbon groups, specifically fluoroalkyl groups and fluorobenzene structures, is preferable.

[0070] (2) Surface eccentricity The fluorine atom-containing polymer added to the resist effectively provides a barrier function by being unevenly distributed on the surface. Conversely, if the fluorine atom-containing polymer is not unevenly distributed on the surface, or if it is unevenly distributed in the layer beneath the resist, it will not exhibit a barrier function between the resist film and the immersion liquid. Creating a difference in surface energy is effective in promoting uneven distribution on the surface, and this is achieved by introducing fluoroalkyl groups or fluorobenzene structures.

[0071] (3) Hydrophobicity The resist surface and lens must move smoothly without leaving any liquid immersion water between them during exposure. This smooth movement is achieved by increasing the contact angle between the protective film surface and water, especially the receding contact angle. For this purpose, the introduction of fluoroalkyl groups or fluorobenzene structures, or branched alkyl groups or aromatic hydrocarbon groups, is effective. If the contact angle is not within the appropriate range, liquid immersion water may remain on the resist surface, resulting in watermark defects where pattern defects appear in the water pattern, or air bubbles may enter the liquid immersion water, causing the refraction angle to fluctuate only in the bubble area during exposure, resulting in bubble defects where pattern defects appear in the bubble pattern.

[0072] (4) Solubility after development It is preferable that the fluorine atom-containing polymer is removed simultaneously with the development of the resist by the developer. Since fluorine atom-containing polymers are generally readily soluble in organic solvents, removal after development is easy in the case of organic solvent development. On the other hand, when using alkaline development, it is preferable to use monomers having alkaline hydrolyzable ester groups or highly acidic hydrophilic groups. In particular, when alkaline hydrolyzable groups are introduced, the contact angle is high during exposure and low during development, and the solubility in the developer increases. If the contact angle after development is high, the hydrophobicity of the resist surface is high, so the rinse solution tends to remain on the resist surface after development, resulting in many blob defects. For this reason, a fluorine atom-containing polymer that is soluble after development is preferred.

[0073] Monomers containing perfluoroalkyl groups and monomers containing trifluoromethyl groups have been used in fluorine atom-containing polymers, but both are subject to PFAS regulations and are compounds with a high environmental impact. On the other hand, the difluorochloro group (CF2Cl-), difluorobromo (CF2Br-), and difluoroiodo (CF2I-) groups represented by formula (d0) do not fall under PFAS regulations, yet they possess sufficient surfactant function, water repellency, and water-sliding properties. Similarly, the difluoro group (CF2H-) does not fall under PFAS regulations, but formula (d0) exhibits higher water repellency and water-sliding properties compared to the trifluoromethyl and difluoro groups. The reason is not clear, but it is thought that the substituent represented by formula (d0) exhibits different orientation than the trifluoromethyl and difluoro groups because it is a substituent that is substituted with one halogen atom other than a fluorine atom in addition to two fluorine atoms. Furthermore, since the difluoro group has a highly acidic hydrogen atom, it acts as a hydrogen bond donor to water molecules and increases hydrophilicity, so in comparison, the substituent represented by formula (d0) has significantly higher water repellency and water-sliding properties.

[0074] The repeating unit represented by formula (D1) has a difluorohalo group and a hydroxyl group. Therefore, polymers containing the repeating unit represented by formula (D1) have improved surface segregation ability, water repellency, and water-sliding properties, while also exhibiting a high dissolution rate in alkaline development. 21and R 22 The number of carbon atoms and the degree of branching can be easily controlled structurally, making it possible to control water repellency and water-sliding properties.

[0075] Furthermore, the repeating unit represented by formula (D1) can have its hydroxyl group protected by an acetal group or a tertiary ester group. In this case, hydrolysis can be induced by the acid or alkaline developer generated after exposure, increasing the hydrophilicity of the resist film surface after development and significantly lowering the surface contact angle after development. As a result, the occurrence of blob defects can be suppressed. Moreover, by increasing the hydrophilicity of the exposed area, it is possible to prevent defects in which insoluble polymer residue remains in the exposed area.

[0076] In particular, in positive tone development using alkaline developers such as TMAH aqueous solution, there is a high risk that highly hydrophobic fluorine atom-containing polymers will remain on the resist film surface and substrate. Therefore, by including repeating units represented by formula (D1) in the fluorine atom-containing polymer, it is possible to prevent adhesion defects of the fluorine atom-containing polymer.

[0077] The repeating units represented by formula (D1) include, but are not limited to, the following. Note that in the following formula, R B This is the same as described above.

[0078] [ka]

[0079] [ka]

[0080] [ka]

[0081] [ka]

[0082] [ka]

[0083] [ka]

[0084] Preferred base-dissociable groups (base hydrolysis groups) are ester bonds (―O―C(=O)-) and reverse ester bonds (―C(=O)-O-). The presence of a unit represented by formula (d0) in the vicinity of these (at a position via a hydrocarbyl group with 1 to 5 carbon atoms) allows the ester bond and reverse ester bond to act as base hydrolysis groups. The presence of repeating units containing base-dissociable groups can impart (4) post-development solubility to fluorine atom-containing polymers. For example, the repeating unit represented by formula (D1) has highly acidic alcohol units, so when used, post-development solubility increases but water repellency decreases, resulting in a decrease in RCA. On the other hand, copolymerizing repeating units having base-dissociable groups in addition to the repeating unit represented by formula (D1) can increase RCA while increasing hydrophilicity after alkaline development, resulting in a reduction of post-development defects.

[0085] The repeating unit having the base-dissociable group and formula (d0) is preferably one represented by formulas (D2) and (D3). In particular, the R 23 Preferably, the group is a linear, branched, or cyclic hydrocarbylene group having 1 to 20 carbon atoms, and more preferably, it contains an alicyclic group or an aromatic ring. With such a structure, it is possible to further increase the RCA. That is, the present invention relates to a fluorine atom-containing polymer that contains a repeating unit including formula (d0) and base hydrolysis as an essential unit, such as formulas (D2) and (D3).

[0086] The repeating unit represented by formula (D2) consists of an ester bond (―O―C(=O)-*) and a unit represented by formula (d0) R 25 It has a structure connected via (where * is R 25 (or bond position with the unit represented by formula (d0)). This structure is characterized by increased solubility in alkaline developer upon the action of alkaline developer. Specifically, the ester group, whose activity is enhanced by the electron-withdrawing ability of formula (d0), undergoes basic hydrolysis due to the basic components contained in the alkaline developer, and the ester bond of formula (D2) dissociates into a hydroxyl group, thereby increasing developer solubility.

[0087] In formula (D2), R 25 Specific examples of linear and branched C1-C5 hydrocarbylene groups represented by include methylene, ethylene, n-propylene, isopropylene, n-butene, sec-butene, tert-butene, n-pentene, and cyclopentyl groups. In particular, methylene and ethylene groups exhibit effective base hydrolysis reactions, resulting in high development defect suppression ability.

[0088] In formula (D2), R 23k R is a (k+1) valence organic group having 1 to 20 carbon atoms, which may contain single bonds or linear, branched, or cyclic heteroatoms. k is an integer from 1 to 3. 23k Examples include a C1-C20 hydrocarbylene group which may contain linear, branched, or cyclic heteroatoms, or a group obtained by removing k-1 hydrogen atoms from the hydrocarbylene group. 23k There are no particular restrictions on the heteroatoms that may be included in the (k+1) valence organic group, but examples include oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms, etc.

[0089] By using a fluorine atom-containing polymer that includes repeating units represented by formula (D2), it is possible not only to exhibit excellent water-repellent and hydrophobic properties, but also to increase the hydrophilicity of the resist film surface after alkaline development, thereby significantly reducing the surface contact angle after development and consequently suppressing development defects such as blob defects.

[0090] The fluorine atom-containing polymer having the substituent represented by formula (d0) of the present invention is non-PFAS, yet it fully satisfies these performance requirements. This is thought to be due to the magnitude of the electron-withdrawing properties of the substituent represented by formula (d0). For example, the pKa of difluorochloroacetic acid containing the substituent represented by formula (d0) of the present invention is about 0.40, while the pKa of difluoroacetic acid is about 1.3. Thus, the electron-withdrawing properties differ greatly between substituents where a carbon atom is substituted with three halogen atoms and substituents where it is substituted with one or more hydrogen atoms. As a result, the basic hydrolysis properties of the ester bond, which depend on the electron-withdrawing properties of the substituent, are improved.

[0091] Furthermore, fluorine-containing polymers having substituents represented by formula (d0) exhibit slightly lower electrophilicity of the ester bond compared to existing fluorine-containing polymers having trifluoromethyl groups. This improves stability with acids and amine quenchers in resists, which was a challenge with existing fluorine-containing polymers. This is thought to be due to the slightly lower electrophilicity of the substituent represented by formula (d0) compared to the trifluoromethyl group, and the fact that it is substituted with sterically bulky chlorine, bromine, or iodine.

[0092] The repeating units represented by formula (D2) include, but are not limited to, the following. Note that in the following formula, R B This is the same as described above.

[0093] [ka]

[0094] [ka]

[0095] [ka]

[0096] [ka]

[0097] Furthermore, the repeating unit (D2) is preferably represented by the following formula (D2-1). [ka] (In the formula, R B , R 25 (X and k are the same as above.)

[0098] The repeating unit represented by formula (D3) consists of an ester bond (―C(=O)-O-*) and a unit represented by formula (d0) R 25 It has a structure connected via (where * is R 25 (or bond position with the unit represented by formula (d0)). This structure is characterized by increased solubility in alkaline developer upon the action of alkaline developer. Specifically, the ester group, whose activity is enhanced by the electron-withdrawing ability of formula (d0), undergoes basic hydrolysis due to the basic components contained in the alkaline developer, and the ester bond of formula (D3) dissociates into a carboxyl group, thereby increasing the solubility in the developer.

[0099] In equation (D3), R 25k R is a (k+1) valence organic group consisting of 1 to 5 carbon atoms, either single-bonded, linear, or branched. k is an integer between 1 and 3. 25k Examples include linear or branched hydrocarbylene groups having 1 to 5 carbon atoms, or groups obtained by removing k-1 hydrogen atoms from the hydrocarbylene group. In formula (D3), R 25k Specific examples of linear and branched C1-C5 hydrocarbylene groups represented by include methylene, ethylene, n-propylene, isopropylene, n-butene, sec-butene, tert-butene, n-pentene, and cyclopentyl groups. In particular, methylene and ethylene groups exhibit effective base hydrolysis reactions, resulting in high development defect suppression ability.

[0100] By using a fluorine atom-containing polymer containing repeating units represented by formula (D3), not only is it possible to achieve excellent water repellency and hydrophobicity, but by increasing the hydrophilicity of the resist film surface after alkaline development, the surface contact angle after development is significantly reduced, and as a result, development defects such as blob defects can be suppressed. Furthermore, the repeating units represented by formula (D3) generate highly acidic carboxyl groups after development, which not only reduces the surface contact angle but also significantly improves the solubility of the fluorine atom-containing polymer. As a result, residue defects caused by insoluble fluorine atom-containing polymer are reduced in both exposed and unexposed areas, resulting in excellent defect suppression ability.

[0101] The fluorine atom-containing polymer having the substituent represented by formula (d0) of the present invention is non-PFAS, yet it fully satisfies these performance requirements. This is thought to be due to the magnitude of the electron-withdrawing properties of the substituent represented by formula (d0). For example, the pKa of difluorochloroacetic acid containing the substituent represented by formula (d0) of the present invention is about 0.40, while the pKa of difluoroacetic acid is about 1.3. Thus, the electron-withdrawing properties differ greatly between substituents where a carbon atom is substituted with three halogen atoms and substituents where it is substituted with one or more hydrogen atoms. As a result, the basic hydrolysis properties of the ester bond, which depend on the electron-withdrawing properties of the substituent, are improved.

[0102] Furthermore, fluorine-containing polymers having substituents represented by formula (d0) exhibit slightly lower electrophilicity of the ester bond compared to existing fluorine-containing polymers having trifluoromethyl groups. This improves stability with acids and amine quenchers in resists, which was a challenge with existing fluorine-containing polymers. This is thought to be due to the slightly lower electrophilicity of the substituent represented by formula (d0) compared to the trifluoromethyl group, and the fact that it is substituted with sterically bulky chlorine, bromine, or iodine.

[0103] The repeating units represented by formula (D3) include, but are not limited to, the following. Note that in the following formula, R B This is the same as described above.

[0104]

Chem.

[0105]

Chem.

[0106]

Chem.

[0107] The fluorine atom-containing polymer of the present invention may include a repeating unit represented by formula (D4), in addition to repeating units represented by formula (D1), formula (D2) and formula (D3). Since the repeating unit represented by formula (D4) has an aromatic ring, it can increase hydrophobicity. It is considered that the fluorine atom-containing polymer has different orientation properties from a fluorine atom-containing polymer consisting only of repeating units having an alkyl chain or an alicyclic group, and is useful for controlling various properties. For example, the receding contact angle can be increased by introducing a monomer having an aromatic ring.

[0108]

Chem.

[0109] In particular, fluorinated benzenes, substituted with fluorine atoms, exhibit high hydrophobicity and can also be given surface segregation, making them useful as fluorine-containing polymers for topcoat-less processes. The number of fluorine atoms substituted on the benzene ring is preferably 1 to 5, and more preferably 4 to 5. In this case, the receding contact angle can be further increased.

[0110] Furthermore, the repeating unit represented by formula (D4) is R 27 It may also contain polar groups such as hydroxyl groups, carboxyl groups, cyano groups, and nitro groups. For example, R 27 When the group is a hydroxyl group, the repeating unit represented by formula (D4) has a phenolic hydroxyl group. Generally, phenolic hydroxyl groups have high acidity, and the acidity is further increased when the benzene ring is substituted with a fluorine atom. As a result, solubility in alkaline developers is improved, and the ability to suppress development defects is enhanced.

[0111] Furthermore, the repeating unit represented by formula (D4) is R 27may contain an acid-labile group or a base-labile group as . When the repeating unit represented by formula (D4) contains an acid-labile group, due to the influence of the acid-labile group with high carbon density, the water repellency and water slidability are high before exposure, and the receding contact angle is significantly increased. On the other hand, after exposure, the acid-labile group is eliminated, making the polymer soluble in an alkaline aqueous solution, and reducing residue defects in exposed areas in positive tone exposure. Furthermore, in lithography using a halftone phase shift mask, since a small amount of light is also transmitted through the mask portion, it is possible to improve the solubility of unexposed areas in the developer after exposure.

[0112] When the repeating unit represented by formula (D4) contains a base-labile group, similar to the case of the repeating units represented by the above formulas (D2) and (D3), the solubility in a developer is significantly improved after alkali development, thereby imparting surface hydrophilicity and making it possible to suppress development defects such as Blob defects.

[0113] Examples of the repeating unit represented by formula (D4) include, but are not limited to, those shown below. In the following formulas, R B is the same as defined above.

[0114]

Chemical Formula

[0115]

Chemical Formula

[0116] The (D) fluorine atom-containing polymer preferably includes the repeating unit represented by the above formula (D2-1) and the repeating unit represented by the following formula (D4-1).

Chemical Formula

[0117] (D) In ​​the fluorine atom-containing polymer, the content of repeating units having a structure represented by formula (d0) and a base-dissociable group (for example, repeating units represented by formula (D2) and repeating units represented by formula (D3)) can be 5 mol% or more, 10 mol% or more, 20 mol% or more, and may be 100 mol%, or may be 90 mol% or less, 80 mol% or less, or 70 mol% or less, of the total repeating units. The content of repeating units represented by formula (D1) can be 0 mol%, and may be 10 mol% or more, 20 mol% or more, 30 mol% or more, 40 mol% or more, and may be 90 mol% or less, 80 mol% or less, 70 mol% or less, or 60 mol% or less, of the total repeating units. The content of repeating units represented by formula (D4) can be 0 to 50% of the total repeating units.

[0118] The fluorine atom-containing polymer may further contain other repeating units other than those represented by any of the formulas (D1) to (D4). For example, other repeating units include those represented by the formulas (B1) to (B3) described below. In the fluorine atom-containing polymer, the content of the repeating units represented by formulas (D1) to (D4) is preferably 20 mol% or more, more preferably 60 mol% or more, and even more preferably 100 mol% of the total repeating units. The content of the repeating unit represented by formula (B1) is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 40 mol% or more. By including a large amount of the repeating unit represented by formula (B1), the receding contact angle before exposure can be increased, and development defects in the exposed area after exposure can be reduced. The content of the repeating units represented by formulas (B2) and (B3) is preferably 10 mol% or more, more preferably 15 mol% or more, and even more preferably 20 mol% or more. By including a large number of repeating units represented by equations (B2) and (B3), the hydrophilicity of the fluorine atom-containing polymer can be moderately increased, suppressing bridge defects in positive tone exposure and improving the pattern's resolution limit. In other words, even with wider line widths, patterns do not bridge to each other and are resolved.

[0119] The Mw of the fluorine atom-containing polymer of component (D) is preferably 1,000 to 100,000, more preferably 3,000 to 18,000, and even more preferably 8,000 to 15,000. When the molecular weight is within this range, surface segregation is good and residue defects are reduced. The Mw / Mn ratio is preferably 1.0 to 2.0, and more preferably 1.0 to 1.6. In this invention, Mw is a polystyrene-converted value measured by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

[0120] As a method for synthesizing the fluorine atom-containing polymer of component (D), a method may be mentioned in which a monomer having a structure represented by formula (d0) and a base-dissociable group (e.g., a monomer that provides a repeating unit represented by formula (D2) and a repeating unit represented by formula (D3)), and if necessary, monomers that provide a repeating unit represented by formula (D1), a repeating unit represented by formula (D4), and other repeating units are polymerized by adding a radical initiator and heating in an organic solvent. Examples of the organic solvent used in the polymerization reaction include toluene, benzene, THF, diethyl ether, dioxane, methyl ethyl ketone, propylene glycol monomethyl ether, PGMEA and the like. Examples of the polymerization initiator include AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl 2,2-azobis(2-methylpropionate), benzoyl peroxide, lauroyl peroxide and the like. The reaction temperature of the polymerization reaction is preferably 50 to 100°C. The addition amount of these initiators is preferably 0.01 to 25 mol% based on the total amount of monomers to be polymerized. The reaction time is preferably 4 to 24 hours. The acid-labile groups introduced into the monomer may be used as they are, or may be protected or partially protected after polymerization. Further, in order to adjust the molecular weight, polymerization may be carried out using a known chain transfer agent such as dodecyl mercaptan or 2-mercaptoethanol. In this case, the addition amount of the chain transfer agent is preferably an amount that gives a molar ratio of 0.01 to 10 relative to the total monomers to be polymerized.

[0121] Incidentally, the repeating unit having a structure represented by formula (d0) and a base-dissociable group (e.g., the repeating unit represented by formula (D2), the repeating unit represented by formula (D3)) and the monomer that provides the repeating unit represented by formula (D1) used in the present invention can be obtained using corresponding raw materials and known organic synthesis reactions as shown in the examples.

[0122] When the chemically amplified resist composition of the present invention contains the fluorine atom-containing polymer as component (D), the content thereof is preferably 0.1 to 50 parts by mass, more preferably 0.1 to 20 parts by mass, and even more preferably 0.5 to 10 parts by mass, relative to 80 parts by mass of the base polymer as component (B). When the content of the fluorine atom-containing polymer (D) falls within the above range, the contact angle between the resist film surface and water can be sufficiently increased, defects caused by residual immersion water, and elution of the photoacid generator and quencher can be suppressed. Furthermore, it becomes possible to adjust the solubility of the resist film surface, and good CDU can be achieved. The fluorine atom-containing polymer (D) may be used alone, or two or more thereof may be used in combination.

[0123] [(A) Photoacid Generator] The photoacid generator (A) is not particularly limited as long as it decomposes upon light irradiation to generate an acid. In order to reduce environmental load, the photoacid generator contained in the chemically amplified resist composition of the present invention is preferably one that does not contain perfluorinated methyl groups or methylene groups (fully fluorinated methyl groups or fully fluorinated methylene groups).

[0124] As the photoacid generator (A) that does not contain perfluorinated methyl groups or methylene groups, those represented by the following formula (a) are preferable. [Chemical Formula] [Chemical Formula] [Chemical Formula] [In the formula, R is a hydrocarbyl group having 1 to 50 carbon atoms which may be substituted with a heteroatom, and L is a divalent linking group represented by formula (a1) or (a2). In formula (a1), m1 is an integer of 1 to 4. R 1 and R 2Each of these is independently a hydrogen atom, a halogen atom other than a fluorine atom, a cyano group, a nitro group, a hydroxyl group, an alkoxy group, an alkylthio group, an amino group, a mercapto group, a pentafluorosulfanyl group, or a C1-C20 hydrocarbyl group, hydrocarbyloxy group, or hydrocarbylthio group, which may contain a heteroatom, and at least one of them is an electron-withdrawing group. In equation (a2), m2 is an integer between 0 and 1. m3 is between 0 and 4 when m2 is 0, and between 0 and 6 when m2 is 1. m4 is between 0 and 4 when m2 is 0, and between 0 and 6 when m2 is 1. However, when m2 is 0, 1 ≤ m3 + m4 ≤ 4, and when m2 is 1, 1 ≤ m3 + m4 ≤ 6. R f R is a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms, or a pentafluorosulfanil group. When there are multiple m3s, each R F These may be identical or different from each other. 3 This is a C1-C20 hydrocarbyl group, hydrocarbyloxy group, or hydrocarbylthio group, which may contain halogen atoms other than fluorine atoms, cyano groups, nitro groups, hydroxyl groups, alkoxy groups, alkylthio groups, amino groups, mercapto groups, or heteroatoms. However, when m3 is 0, R 3 At least one of them is an electron-withdrawing group. In equations (a1) and (a2), * represents L A ** indicates the binding site with the sulfonate anion. Z + This is a sulfonium cation represented by the following formula (Z-1) or an iodonium cation represented by the following formula (Z-2). [ka] (In the formula, R ct1 ~R ct5 Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain a halogen atom or a heteroatom. ct1 and R ct2may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.)]

[0125] Specific examples of the anion of the photoacid generator represented by formula (a) are shown below, but are not limited thereto.

[0126]

Chemical Formula

[0127]

Chemical Formula

[0128]

Chemical Formula

[0129] Further, as the photoacid generator represented by the following formula (a), a photoacid generator wherein R in the formula is represented by the following formula (r) is more preferable. With such a photoacid generator, acid diffusion can be effectively suppressed, and CDU and LWR are improved.

Chemical Formula

[0130] Specific examples of the anion of the photoacid generator are shown below, but are not limited thereto.

[0131]

Chemical Formula

[0132] [ka]

[0133] [ka]

[0134] [ka]

[0135] [ka]

[0136] [ka]

[0137] Furthermore, a photoacid generator represented by the following formula (a3) ​​is also preferred. [ka] (In the formula, X is a carbon atom or a nitrogen atom.) m1 is 1, 2, 3, 4, or 5. m2 is 0, 1, 2, 3, or 4, where 1 ≤ m1 + m2 ≤ 5. When X is a carbon atom, m3 is 1, 2, or 3, m4 is 0, 1, or 2, and m3 + m4 = 3. When X is a nitrogen atom, m3 is 1 or 2, m4 is 0 or 1, and m3 + m4 = 2. R 1This is a C1-C20 hydrocarbyl group which may contain halogen atoms other than fluorine, a nitro group, a hydroxyl group, a cyano group, a heteroatom, a C1-C20 hydrocarbyloxy group which may contain a heteroatom, or a C1-C20 hydrocarbylthio group which may contain a heteroatom. When m2 is 2, 3, or 4, each R 1 These may be the same or different from each other, and there may be multiple R 1 However, they may bond with each other to form a ring with the carbon atoms to which they are bonded. R 2 This is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a fluorine atom or a heteroatom. Z + (This is the same as above.)

[0138] Specific examples of the photoacid generator anion represented by formula (a3) ​​are shown below, but are not limited to these.

[0139] [ka]

[0140] [ka]

[0141] [ka]

[0142] In formula (a3), Z + This is a sulfonium cation represented by the following formula (Z-1) or an iodonium cation represented by the following formula (Z-2). [ka]

[0143] In equations (Z-1) and (Z-2), R ct1 ~R ct5Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain a halogen atom or a heteroatom.

[0144] R ct1 ~R ct5 Specific examples of halogen atoms represented by include fluorine, chlorine, bromine, and iodine atoms.

[0145] R ct1 ~R ct5 The hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include C1-C30 alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl groups; C3-C30 cyclic saturated hydrocarbyl groups such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl groups; C2-C30 alkenyl groups such as vinyl, allyl, propenyl, butenyl, and hexenyl groups; C3-C30 cyclic unsaturated hydrocarbyl groups such as cyclohexenyl groups; C6-C30 aryl groups such as phenyl, naphthyl, and thienyl groups; C7-C30 aralkyl groups such as benzyl, 1-phenylethyl, and 2-phenylethyl groups; and groups obtained by combining these, but aryl groups are preferred. Furthermore, some or all of the hydrogen atoms of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, nitrogen atom, or halogen atom, and some of the -CH2- of the hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom, sulfur atom, or nitrogen atom, and as a result, it may contain 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 sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc.

[0146] Also, R ct1 and Rct2 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded. In this case, specific examples of the structure of the ring include those represented by the following formula.

[0147] [ka] (In the formula, the dashed line represents R ct3 (This is a combination of the two.)

[0148] Specific examples of sulfonium cations represented by formula (Z-1) are listed below, but are not limited to these.

[0149] [ka]

[0150] [ka]

[0151] [ka]

[0152] [ka]

[0153] [ka]

[0154] [ka]

[0155] [ka]

[0156]

change

[0157]

change

[0158]

change

[0159]

change

[0160]

change

[0161]

change

[0162]

change

[0163]

change

[0164]

change

[0165]

change

[0166]

change

[0167]

change

[0168]

change

[0169]

change

[0170]

change

[0171]

change

[0172]

change

[0173]

change

[0174]

change

[0175]

change

[0176]

change

[0177]

change

[0178] [ka]

[0179] [ka]

[0180] [ka]

[0181] [ka]

[0182] [ka]

[0183] [ka]

[0184] [ka]

[0185] Specific examples of iodonium cations represented by formula (Z-2) are listed below, but are not limited to these.

[0186] [ka]

[0187] [ka]

[0188] Specific examples of photoacid generators represented by formula (a3) ​​include any combination of anion and cation as described above.

[0189] The methidic acid and imido acid generated from the photoacid generator (onium salt) represented by formula (a3) ​​have extremely high acid strength because the anionic moiety is surrounded by three sulfonyl groups in the case of methidic acid and two sulfonyl groups in the case of imido acid. In addition, the anionic moiety is sterically crowded because it is surrounded by sulfonium groups. Therefore, it has the characteristic of suppressing the diffusion distance of the generated acid. In the onium salt represented by formula (a3), it is preferable that X is a carbon atom, that is, that the anion is a methidic acid anion. Since methidic acid has a lower acid diffusion distance than imido acid, the lithography performance of CDU, LWR, MEF, etc. is further improved.

[0190] By using a photoacid generator consisting of an onium salt represented by formula (a3), sensitivity is improved compared to using conventional photoacid generators that generate alkanesulfonic acids or arylsulfonic acids. Furthermore, since the methidic acid or imido acid generated from the photoacid generator has a structure substituted with fluorinated benzene, the diffusion of the generated acid can be suppressed compared to resist compositions using onium salts that generate similar methidic acid or imido acid as photoacid generators, thereby improving lithography performance such as LWR, CDU, and MEF.

[0191] The onium salt can be synthesized by known methods. Specifically, it can be synthesized by the method described in Japanese Patent Publication No. 7067271, but the method for synthesizing the onium salt is not limited thereto.

[0192] In the chemically amplified resist composition of the present invention, the content of the photoacid generator consisting of the onium salt of component (A) is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 30 parts by mass, relative to 80 parts by mass of the base polymer described later. When the content of component (A) is within the above range, the sensitivity and resolution are good, and there is no risk of foreign matter problems occurring after development or peeling of the resist film, so it is preferable. The photoacid generator (A) may be used alone or in combination of two or more types.

[0193] [(B) Base polymer] The chemically amplified resist composition of the present invention comprises a base polymer having an acid-unstable group as component (B).

[0194] The repeating unit having the acid-unstable group is preferably represented by the following formula (B1). [ka]

[0195] In formula (B1), R A This is either a hydrogen atom or a methyl group.

[0196] In formula (B1), R AL This is an acid-unstable group. Various acid-unstable groups can be used, but specifically, examples include the group represented by the following formulas (L1) to (L9), a tertiary hydrocarbyl group having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms, a trihydrocarbylsilyl group in which each hydrocarbyl group has 1 to 6 carbon atoms, a carbonyl group, a hydrocarbyl group having 4 to 20 carbon atoms containing an ether bond or an ester bond, etc.

[0197] [ka] (In the equation, dashed lines represent connections.)

[0198] In formula (L1), R L01 and R L02Each of these is independently a hydrogen atom or a saturated hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. Specific examples include alkyl groups having 1 to 18 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-ethylhexyl, and n-octyl groups; and cyclic saturated hydrocarbyl groups having 3 to 18 carbon atoms such as cyclopentyl, cyclohexyl, norbornyl, tricyclodecyl, tetracyclododecyl, and adamantyl groups.

[0199] In formula (L1), R L03 This is a hydrocarbyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, which may contain heteroatoms. Examples of the heteroatoms include oxygen atoms, nitrogen atoms, sulfur atoms, etc. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic, but a saturated hydrocarbyl group is preferred. Furthermore, some of the hydrogen atoms of the saturated hydrocarbyl group may be substituted with a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, an oxo group, an amino group, a saturated hydrocarbylamino group having 1 to 8 carbon atoms, etc., and some of the -CH2- of the saturated hydrocarbyl group may be substituted with a group containing a heteroatom such as an oxygen atom. As for the saturated hydrocarbyl group, L01 and R L02 Examples of saturated hydrocarbyl groups represented by the formula shown are similar to those exemplified above. Furthermore, examples of substituted saturated hydrocarbyl groups include the following groups.

[0200] [ka] (In the equation, dashed lines represent connections.)

[0201] R L01 , R L02 and R L03Any two of these may bond with each other to form a ring with the carbon and oxygen atoms to which they bond. When a ring is formed, the group formed by their bonding is preferably an alkanediyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms.

[0202] In formula (L2), R L04 k is a tertiary hydrocarbyl group having 4 to 20 carbon atoms, preferably 4 to 15 carbon atoms; a trihydrocarbyl silyl group in which each hydrocarbyl group has 1 to 6 carbon atoms; a carbonyl group; a saturated hydrocarbyl group having 4 to 20 carbon atoms including an ether bond or an ester bond; or a group represented by formula (L1). k is 0, 1, 2, 3, 4, 5, or 6.

[0203] R L04 The tertiary hydrocarbyl group represented by can be branched or cyclic, and specific examples include tert-butyl group, tert-pentyl group, 1,1-diethylpropyl group, 2-cyclopentylpropan-2-yl group, 2-cyclohexylpropan-2-yl group, 2-(bicyclo[2.2.1]heptan-2-yl)propan-2-yl group, 2-(adamantan-1-yl)propan-2-yl group, 1-ethylcyclopentyl group, 1-butylcyclopentyl group, 1-ethylcyclohexyl group, 1-butylcyclohexyl group, 1-ethyl-2-cyclopentenyl group, 1-ethyl-2-cyclohexenyl group, 2-methyl-2-adamantyl group, and 2-ethyl-2-adamantyl group. Specific examples of the trihydrocarbyl silyl group include trimethylsilyl group, triethylsilyl group, and dimethyl-tert-butylsilyl group. Examples of saturated hydrocarbyl groups containing the carbonyl group, ether bond, or ester bond include, specifically, 3-oxocyclohexyl group, 4-methyl-2-oxooxan-4-yl group, and 5-methyl-2-oxooxolan-5-yl group.

[0204] In formula (L3), R L05This is a saturated hydrocarbyl group having 1 to 8 carbon atoms, which may contain heteroatoms, or an aryl group having 6 to 20 carbon atoms, which may contain heteroatoms and may be substituted. The saturated hydrocarbyl group may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, and n-hexyl groups; and cyclic saturated hydrocarbyl groups such as cyclopentyl and cyclohexyl groups. Furthermore, some of the hydrogen atoms of the saturated hydrocarbyl group may be substituted with hydroxyl groups, saturated hydrocarbyloxy groups having 1 to 8 carbon atoms, carboxyl groups, saturated hydrocarbyloxycarbonyl groups having 1 to 8 carbon atoms, oxo groups, amino groups, saturated hydrocarbylamino groups having 1 to 8 carbon atoms, cyano groups, mercapto groups, saturated hydrocarbylthio groups having 1 to 8 carbon atoms, sulfo groups, etc. Specific examples of the aryl group include phenyl group, methylphenyl group, naphthyl group, anthryl group, phenanthryl group, pyrenyl group, etc. Furthermore, some of the hydrogen atoms of the aryl group may be substituted with a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, a carboxyl group, a saturated hydrocarbylcarbonyl group having 1 to 8 carbon atoms, an oxo group, an amino group, a saturated hydrocarbylamino group having 1 to 8 carbon atoms, a cyano group, a mercapto group, a saturated hydrocarbylthio group having 1 to 8 carbon atoms, a sulfo group, etc.

[0205] In equation (L3), m is 0 or 1, n is 0, 1, 2 or 3, and 2m + n = 2 or 3.

[0206] In formula (L4), R L06 This is a C1-C8 hydrocarbyl group which may contain a heteroatom, or a C6-C20 aryl group which may contain a heteroatom. Specific examples of the saturated hydrocarbyl group and aryl group are, respectively, R L05Examples of saturated hydrocarbyl groups and aryl groups represented by the formulas shown are similar to those exemplified. Furthermore, some of the hydrogen atoms of the saturated hydrocarbyl groups and aryl groups may be substituted with hydroxyl groups, saturated hydrocarbyloxy groups having 1 to 8 carbon atoms, carboxyl groups, saturated hydrocarbylcarbonyl groups having 1 to 8 carbon atoms, oxo groups, amino groups, saturated hydrocarbylamino groups having 1 to 8 carbon atoms, cyano groups, mercapto groups, saturated hydrocarbylthio groups having 1 to 8 carbon atoms, sulfo groups, etc.

[0207] In formula (L4), R L07 ~R L16 Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 15 carbon atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic, but a saturated hydrocarbyl group is preferred. Specific examples of the hydrocarbyl group include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-octyl, n-nonyl, and n-decyl groups; and cyclic saturated hydrocarbyl groups such as cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, and cyclohexylbutyl groups. Furthermore, some of the hydrogen atoms of the hydrocarbyl group may be substituted with a hydroxyl group, a saturated hydrocarbyloxy group having 1 to 8 carbon atoms, a carboxyl group, a saturated hydrocarbyloxycarbonyl group having 1 to 8 carbon atoms, an oxo group, an amino group, a saturated hydrocarbylamino group having 1 to 8 carbon atoms, a cyano group, a mercapto group, a saturated hydrocarbylthio group having 1 to 8 carbon atoms, a sulfo group, etc. L07 ~R L16 Two of these may be selected and bonded together to form a ring with the carbon atoms to which they are bonded (for example, R L07 and R L08 , R L07 and R L09 , R L08 and R L10 , R L09 and R L10 , R L11and R L12 , R L13 and R L14 In such cases, the group involved in ring formation is a hydrocarbylene group having 1 to 15 carbon atoms. Specific examples of the hydrocarbylene group include those obtained by removing one hydrogen atom from the hydrocarbyl group exemplified above. Also, R L07 ~R L16 These atoms may bond to adjacent carbon atoms without any intermediaries, forming a double bond (for example, R L07 and R L09 , R L09 and R L15 , R L13 and R L15 etc.).

[0208] In formula (L5), R L17 ~R L19 Each of these is independently a saturated hydrocarbyl group having 1 to 15 carbon atoms, which may contain heteroatoms, or an aryl group having 6 to 15 carbon atoms, which may contain heteroatoms. The saturated hydrocarbyl group may be linear, branched, or cyclic. Specific examples include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, 2-ethylhexyl, and n-octyl; and cyclic saturated hydrocarbyl groups such as cyclopentyl, cyclohexyl, 1-adamantyl, and 2-adamantyl. Examples of the aryl group include phenyl and naphthyl groups. The aryl group may contain hydroxyl, halogen, and other elements.

[0209] In formula (L6), R L20 This is a saturated hydrocarbyl group having 1 to 10 carbon atoms, which may contain heteroatoms, or an aryl group having 6 to 20 carbon atoms, which may contain heteroatoms. Specific examples of the cyclic saturated hydrocarbyl group and aryl group are, respectively, R L05 Examples of saturated hydrocarbyl groups and aryl groups represented by the formula are similar to those exemplified above.

[0210] In formula (L7), R L21This is a saturated hydrocarbyl group having 1 to 10 carbon atoms, which may contain heteroatoms, or an aryl group having 6 to 20 carbon atoms, which may contain heteroatoms. Specific examples of the cyclic saturated hydrocarbyl group and aryl group are, respectively, R L05 Examples of saturated hydrocarbyl groups and aryl groups represented by the formula are similar to those exemplified above.

[0211] R L22 and R L23 Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R L07 ~R L16 Examples of hydrocarbyl groups represented by are similar to those exemplified. Also, R L22 and R L23 These may bond to each other to form a substituted or unsubstituted cyclopentane ring or a substituted or unsubstituted cyclohexane ring with the carbon atoms to which they are bonded. L24 p is a divalent group that, together with the carbon atom to which it is bonded, forms a substituted or unsubstituted cyclopentane ring, a substituted or unsubstituted cyclohexane ring, or a substituted or unsubstituted norbornane ring. p is 1 or 2.

[0212] In formula (L8), R L25 This is a saturated hydrocarbyl group having 1 to 10 carbon atoms, which may contain heteroatoms, or an aryl group having 6 to 20 carbon atoms, which may contain heteroatoms. Specific examples of the saturated hydrocarbyl group and the aryl group are, respectively, R L05 Examples of saturated hydrocarbyl groups and aryl groups represented by R are similar to those exemplified. L26 and R L27 Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R L07 ~R L16Examples of hydrocarbyl groups represented by are similar to those exemplified. Also, R L26 and R L27 These may bond to each other to form a substituted or unsubstituted cyclopentane ring or a substituted or unsubstituted cyclohexane ring with the carbon atoms to which they are bonded. L28 q is a divalent group that, together with the carbon atom to which it is bonded, forms a substituted or unsubstituted cyclopentane ring, a substituted or unsubstituted cyclohexane ring, or a substituted or unsubstituted norbornane ring. q is 1 or 2.

[0213] In formula (L9), R L29 This is a saturated hydrocarbyl group having 1 to 10 carbon atoms, which may contain heteroatoms, or an aryl group having 6 to 20 carbon atoms, which may contain heteroatoms. Specific examples of the saturated hydrocarbyl group and the aryl group are, respectively, R L05 Examples of saturated hydrocarbyl groups and aryl groups represented by the formula shown are similar to those exemplified.

[0214] R L30 and R L31 Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic. A specific example is R L07 ~R L16 Examples of hydrocarbyl groups represented by are similar to those exemplified. Also, R L30 and R L31 These may bond to each other to form a substituted or unsubstituted cyclopentane ring or a substituted or unsubstituted cyclohexane ring with the carbon atoms to which they are bonded. L32 It is a divalent group that, together with the carbon atom to which it is bonded, forms a substituted or unsubstituted cyclopentane ring, a substituted or unsubstituted cyclohexane ring, or a substituted or unsubstituted norbornane ring.

[0215] Specific examples of acid-unstable groups represented by formula (L1), whether linear or branched, are listed below, but are not limited to these.

[0216] [ka]

[0217] Specific examples of cyclic acid-unstable groups represented by formula (L1) include tetrahydrofuran-2-yl group, 2-methyltetrahydrofuran-2-yl group, tetrahydropyran-2-yl group, and 2-methyltetrahydropyran-2-yl group.

[0218] Specific examples of acid-unstable groups represented by formula (L2) include tert-butoxycarbonyl group, tert-butoxycarbonylmethyl group, tert-pentyloxycarbonyl group, tert-pentyloxycarbonylmethyl group, 1,1-diethylpropyloxycarbonyl group, 1,1-diethylpropyloxycarbonylmethyl group, 1-ethylcyclopentyloxycarbonyl group, 1-ethylcyclopentyloxycarbonylmethyl group, 1-ethyl-2-cyclopentenyloxycarbonyl group, 1-ethyl-2-cyclopentenyloxycarbonylmethyl group, 1-ethoxyethoxycarbonylmethyl group, 2-tetrahydropyranyloxycarbonylmethyl group, and 2-tetrahydrofuranyloxycarbonylmethyl group.

[0219] Specific examples of acid-unstable groups represented by formula (L3) include 1-methylcyclopentyl group, 1-ethylcyclopentyl group, 1-n-propylcyclopentyl group, 1-isopropylcyclopentyl group, 1-n-butylcyclopentyl group, 1-sec-butylcyclopentyl group, 1-tert-butylcyclopentyl group, 1-cyclohexylcyclopentyl group, 1-(4-methoxy-n-butyl)cyclopentyl group, 1-methylcyclohexyl group, 1-ethylcyclohexyl group, 3-methyl-1-cyclopenten-3-yl group, 3-ethyl-1-cyclopenten-3-yl group, 3-methyl-1-cyclohexen-3-yl group, and 3-ethyl-1-cyclohexen-3-yl group.

[0220] Among the acid-unstable groups represented by formula (L4), the groups represented by the following formulas (L4-1) to (L4-4) are particularly preferred.

[0221] [ka]

[0222] In equations (L4-1) to (L4-4), the dashed lines indicate the bond position and direction. L41 Each of these is independently a hydrocarbyl group having 1 to 10 carbon atoms. The hydrocarbyl group may be saturated or unsaturated, and may be linear, branched, or cyclic, but a saturated hydrocarbyl group is preferred. Specific examples of the hydrocarbyl group include alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, and n-hexyl; and cyclic saturated hydrocarbyl groups such as cyclopentyl and cyclohexyl.

[0223] Formulas (L4-1) to (L4-4) may have stereoisomers (enantiomers or diastereomers), but formulas (L4-1) to (L4-4) represent all of these stereoisomers. If the acid-unstable group is the group represented by formula (L4), multiple stereoisomers may be included.

[0224] For example, formula (L4-3) represents one or a mixture of two groups selected from the groups represented by the following formulas (L4-3-1) and (L4-3-2).

[0225] [ka] (In the formula, dashed lines indicate the joint position and direction.)

[0226] Furthermore, formula (L4-4) shall represent one or more groups selected from the groups represented by the following formulas (L4-4-1) to (L4-4-4).

[0227] [ka] (In the formula, dashed lines indicate the joint position and direction.)

[0228] Formulas (L4-1) to (L4-4), (L4-3-1), (L4-3-2), and (L4-4-1) to (L4-4-4) also represent their enantiomers and enantiomer mixtures.

[0229] Furthermore, the bonding direction of formulas (L4-1)~(L4-4), (L4-3-1), (L4-3-2), and (L4-4-1)~(L4-4-4) is on the exo side with respect to the bicyclo[2.2.1]heptane ring, which enables high reactivity in acid-catalyzed elimination reactions (see Japanese Patent Publication No. 2000-336121). In the production of monomers having a tertiary exo-saturated hydrocarbyl group as a substituent on a bicyclo[2.2.1]heptane skeleton, monomers substituted with endo-saturated hydrocarbyl groups represented by the following formulas (L4-1-endo)~(L4-4-endo) may be included, but in order to achieve good reactivity, the exo ratio is preferably 50 mol% or more, and more preferably 80 mol% or more.

[0230] [ka] (In the formula, dashed lines indicate the joint position and direction.)

[0231] Examples of acid-unstable groups represented by formula (L4) include, but are not limited to, the following groups.

[0232] [ka] (In the formula, dashed lines indicate the joint position and direction.)

[0233] Examples of acid-unstable groups represented by formula (L5) include, but are not limited to, the tert-butyl group, the tert-pentyl group, and the groups listed below.

[0234] [ka] (In the equation, dashed lines represent connections.)

[0235] Examples of acid-unstable groups represented by formula (L6) include, but are not limited to, the following groups.

[0236] [ka] (In the equation, dashed lines represent connections.)

[0237] Examples of acid-unstable groups represented by formula (L7) include, but are not limited to, the following groups.

[0238] [ka] (In the equation, dashed lines represent connections.)

[0239] Examples of acid-unstable groups represented by formula (L8) include, but are not limited to, the following groups.

[0240] [ka] (In the equation, dashed lines represent connections.)

[0241] Examples of acid-unstable groups represented by formula (L9) include, but are not limited to, the following groups.

[0242] [ka] (In the equation, dashed lines represent connections.)

[0243] Also, R ALSpecific examples of acid-unstable groups represented by tertiary hydrocarbyl groups with 4 to 20 carbon atoms, trihydrocarbylsilyl groups where each hydrocarbyl group has 1 to 6 carbon atoms, carbonyl groups, and hydrocarbyl groups with 4 to 20 carbon atoms containing ether or ester bonds, are as follows: L04 Examples include tertiary hydrocarbyl groups, trihydrocarbyl silyl groups, and carbonyl groups, as well as saturated hydrocarbyl groups having 4 to 20 carbon atoms that include ether or ester bonds, similar to those exemplified.

[0244] Specific examples of repeating units represented by formula (B1) are, but are not limited to, those listed below. Note that in the formula below, R A This is the same as above.

[0245] [ka]

[0246] [ka]

[0247] [ka]

[0248] [ka]

[0249] [ka]

[0250] The polymer may optionally further include at least one selected from the repeating units represented by the following formula (B2), the following formula (B3), and the following formula (B4).

[0251] [ka]

[0252] In formulas (B2) to (B4), R A R is a hydrogen atom or a methyl group. 11 and R 12 Each of these is independently either a hydrogen atom or a hydroxyl group. 13 R is a substituent having a lactone structure or a substituent having a sultone structure. 14 This is a hydrogen atom, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or a monovalent fluoroalcohol-containing substituent having 1 to 15 carbon atoms.

[0253] Specific examples of repeating units represented by formula (B2) are, but are not limited to, those listed below. Note that in the formula below, R A This is the same as above.

[0254] [ka]

[0255] Specific examples of repeating units represented by formula (B3) are, but are not limited to, those listed below. Note that in the formula below, R A This is the same as above.

[0256] [ka]

[0257] [ka]

[0258] [ka]

[0259] [ka]

[0260] [ka]

[0261] Specific examples of repeating units represented by formula (B4) are listed below, but are not limited to these.

[0262] [ka]

[0263] The polymer may further contain repeating units that do not contain other aromatic groups other than those described above. For example, substituted acrylic acid esters such as methyl methacrylate, methyl crotate, dimethyl maleate, and dimethyl itaconate; unsaturated carboxylic acids such as maleic acid, fumaric acid, and itaconic acid; norbornene, norbornene derivatives, and tetracyclo[4.4.0.1 2,5 .17 7,10 It may also contain repeating units derived from monomers that do not contain aromatic groups, such as cyclic olefins such as dodecene derivatives; unsaturated acid anhydrides such as itaconic anhydride; and monomers that do not contain aromatic groups, such as α-methylene-γ-butyrolactones.

[0264] The polymer may further include repeating units containing other aromatic groups besides those described above. For example, specific examples of repeating units containing aromatic groups are, but are not limited to, those listed below.

[0265] [ka]

[0266] Note that (B) base polymer and the aforementioned (D) fluorine atom-containing polymer are different components. (B) base polymer does not contain the repeating units represented by the above formulas (D1) to (D3).

[0267] The weight-average molecular weight (Mw) of the polymer is preferably 1,000 to 500,000, and more preferably 3,000 to 100,000. Within this range, there is no risk of reduced etching resistance or loss of resolution due to insufficient contrast before and after exposure. In this invention, Mw is a polystyrene-converted value measured by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as the solvent.

[0268] If the polymer has a broad molecular weight distribution (Mw / Mn), it may contain both low-molecular-weight and high-molecular-weight polymers, which may result in foreign matter being visible on the pattern or deterioration of the pattern shape after exposure. As the pattern rules become finer, the influence of Mw and Mw / Mn tends to increase. Therefore, to obtain a resist composition suitable for fine pattern dimensions, it is preferable that the Mw / Mn of the polymer be narrowly dispersed, between 1.0 and 2.0, and particularly between 1.0 and 1.5.

[0269] One method for synthesizing the polymer is to polymerize monomers that provide repeating units represented by formula (B1) and, if necessary, repeating units represented by formulas (B2) to (B4) and other repeating units, by heating them in an organic solvent with a radical initiator. Examples of organic solvents used in the polymerization reaction include toluene, benzene, THF, diethyl ether, dioxane, methyl ethyl ketone, γ-butyrolactone, and propylene glycol monomethyl ether acetate (PGMEA). Examples of polymerization initiators include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile), dimethyl-2,2-azobis(2-methylpropionate), benzoyl peroxide, and lauroyl peroxide. The amount of these initiators added is preferably 0.01 to 25 mol% of the total amount of monomers to be polymerized. The reaction temperature for the polymerization reaction is preferably 50 to 150°C, more preferably 60 to 100°C. The reaction time is preferably 2 to 24 hours. The acid-unstable group may be used as is after being introduced into the monomer, or it may be protected or partially protected after polymerization. In addition, known chain transfer agents such as dodecyl mercaptan and 2-mercaptoethanol may be used to adjust the molecular weight during polymerization. In this case, the amount of chain transfer agent added is preferably in a molar ratio of 0.01 to 10 relative to the total monomer to be polymerized.

[0270] In the polymer, the preferred content ratio of each repeating unit can be, for example, within the range shown below, but is not limited thereto.

[0271] (I) The repeating unit represented by formula (B1) is preferably 1 to 99 mol%, more preferably 20 to 95 mol%, more preferably 30 to 90 mol%, and as needed, (II) At least one selected from the repeating units represented by formula (B2), formula (B3), and formula (B4) is preferably contained in an amount of 0 to 99 mol%, more preferably 1 to 90 mol%, and even more preferably 10 to 70 mol%, (III) Other repeating units may be included, preferably in an amount of 0 to 99 mol%, more preferably 0 to 70 mol%, and even more preferably 0 to 50 mol%.

[0272] Furthermore, the base polymer of component (B) may be used alone, or two or more types with different composition ratios, Mw, and / or Mw / Mn may be used in combination.

[0273] [(C) Organic Solvents] The chemically amplified resist composition of the present invention contains an organic solvent as component (C). Examples of the aforementioned organic solvents include ketones such as cyclohexanone and methyl-2-n-pentyl ketone, alcohols such as 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and diacetone alcohol, as described in paragraphs

[0144] to

[0145] of Japanese Patent Publication No. 2008-111103; ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, and diethylene glycol dimethyl ether; esters such as PGMEA, propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, and propylene glycol monotert-butyl ether acetate; lactones such as γ-butyrolactone; and mixed solvents thereof. When using acetal-based acid-unstable groups, high-boiling point alcohol-based solvents, specifically diethylene glycol, propylene glycol, glycerin, 1,4-butanediol, 1,3-butanediol, etc., can be added to accelerate the deprotection reaction of the acetal.

[0274] The content of the organic solvent in component (C) is preferably 100 to 10,000 parts by mass, and more preferably 300 to 8,000 parts by mass, per 80 parts by mass of the base polymer of component (B). The organic solvent in (C) may be used alone or as a mixture of two or more types.

[0275] [(E) Quencher] The chemically amplified resist composition of the present invention may optionally contain a quencher as component (E). In the present invention, a quencher means a compound that can prevent the diffusion of acid generated from the photoacid generator into unexposed areas by trapping the acid.

[0276] Specific examples of the quencher include amine compounds, sulfonates, or carboxylates. As the amine compound, primary, secondary, or tertiary amine compounds described in paragraphs

[0146] to

[0164] of Japanese Patent Publication No. 2008-111103 are preferred, particularly amine compounds having any of the following: a hydroxyl group, an ether bond, an ester bond, a lactone ring, a cyano group, or a sulfonic acid ester bond. Compounds in which a primary or secondary amine is protected as a carbamate group, such as the compound described in Japanese Patent Publication No. 3790649, are also preferred. Such protected amine compounds are effective when there are components in the resist composition that are unstable to a base.

[0277] A specific example of the sulfonate salt is the compound represented by the following formula (E1). A specific example of the carboxylate salt is the compound represented by the following formula (E2). [ka]

[0278] In formula (E1), R 31 This refers to a hydrocarbyl group having 1 to 40 carbon atoms, which may contain a hydrogen atom or a heteroatom, but excludes those in which the hydrogen atom bonded to the α-carbon atom of the sulfo group is substituted with a fluorine atom or a fluoroalkyl group.

[0279] R 31 The C1-C40 hydrocarbyl group represented by can be saturated or unsaturated, and can be linear, branched, or cyclic. Specific examples include C1-C40 alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, tert-pentyl, n-pentyl, n-hexyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; cyclopentyl, cyclohexyl, cyclopentylmethyl, cyclopentylethyl, cyclopentylbutyl, cyclohexylmethyl, cyclohexylethyl, cyclohexylbutyl, norbornyl, and tricyclo[5.2.1.0 2,6 ]C3-40 cyclic saturated hydrocarbyl groups such as decyl group, adamantyl group, and adamantylmethyl group; C2-40 alkenyl groups such as vinyl group, 1-propenyl group, 2-propenyl group, butenyl group, and hexenyl group; C3-40 unsaturated aliphatic cyclic hydrocarbyl groups such as cyclohexenyl group; phenyl group, naphthyl group, alkylphenyl group (2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butyl group) Examples include aryl groups with 6 to 40 carbon atoms, such as phenyl groups (e.g., 4-n-butylphenyl groups), dialkylphenyl groups (e.g., 2,4-dimethylphenyl groups), trialkylphenyl groups (e.g., 2,4,6-triisopropylphenyl groups), alkylnaphthyl groups (e.g., methylnaphthyl groups, ethylnaphthyl groups), and dialkylnaphthyl groups (e.g., dimethylnaphthyl groups, diethylnaphthyl groups); and aralkyl groups with 7 to 40 carbon atoms, such as benzyl groups, 1-phenylethyl groups, and 2-phenylethyl groups.

[0280] Furthermore, 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- of the hydrocarbyl group may be substituted with a group containing heteroatoms such as oxygen, sulfur, or nitrogen atoms, and as a result, it may contain a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, a thioether bond, an ester bond, a sulfonic acid ester bond, a carbonate bond, a lactone ring, a sultone ring, a carboxylic acid anhydride (-C(=O)-OC(=O)-), a haloalkyl group, etc. Examples of hydrocarbyl groups containing heteroatoms include heteroaryl groups such as thienyl groups; alkoxyphenyl groups such as 4-hydroxyphenyl, 4-methoxyphenyl, 3-methoxyphenyl, 2-methoxyphenyl, 4-ethoxyphenyl, 4-tert-butoxyphenyl, and 3-tert-butoxyphenyl groups; alkoxynaphthyl groups such as methoxynaphthyl, ethoxynaphthyl, n-propoxynaphthyl, and n-butoxynaphthyl groups; dialkoxynaphthyl groups such as dimethoxynaphthyl and diethoxynaphthyl groups; and aryloxoalkyl groups such as 2-aryl-2-oxoethyl groups such as 2-phenyl-2-oxoethyl, 2-(1-naphthyl)-2-oxoethyl, and 2-(2-naphthyl)-2-oxoethyl groups.

[0281] R 32 R is a hydrocarbyl group having 1 to 40 carbon atoms, which may contain heteroatoms. 32 The hydrocarbyl group represented by R is 31 Examples of hydrocarbyl groups represented by the same formula as those exemplified above include the trifluoromethyl group, trifluoroethyl group, 2,2,2-trifluoro-1-methyl-1-hydroxyethyl group, 2,2,2-trifluoro-1-(trifluoromethyl)-1-hydroxyethyl group, and other fluorine-containing alkyl groups; and fluorine-containing aryl groups such as the pentafluorophenyl group and 4-trifluoromethylphenyl group.

[0282] Specific examples of sulfonate anions represented by formula (E1) are listed below, but are not limited to these.

[0283] [ka]

[0284] [ka]

[0285] Specific examples of anions of carboxylate salts represented by formula (E2) are listed below, but are not limited to these.

[0286] [ka]

[0287] In equations (E1) and (E2), MQ + This is an onium cation. Examples of the onium cation include sulfonium cations, iodonium cations, and ammonium cations. The sulfonium cation is preferably represented by formula (Z-1), and specific examples include those similar to those exemplified as specific examples of sulfonium cations represented by formula (Z-1). The iodonium cation is preferably represented by formula (Z-2), and specific examples include those similar to those exemplified as specific examples of iodonium cations represented by formula (Z-2).

[0288] Furthermore, it is also possible to use a quencher represented by the following formula (q). [ka] [In the general formula (q), R is a nitrogen-containing heterocycle, or (R 4 )(R 5 )NL-*** (q3) It is the group shown by . In general formula (q3), R 4 and R 5 R is a hydroxyl group having 1 to 20 carbon atoms, which may be independently substituted with hydrogen atoms or heteroatoms. 4 and R 5 These atoms may bond to each other to form a ring with the nitrogen atom in general formula (q3). L represents a 1-20 carbon atom hydrocarbylene group, which may be substituted with a heteroatom. *** represents L A This shows the connection point. L A This is a hydroxylene group having 1 to 10 carbon atoms, which may contain a single bond, or an ether bond, ester bond, amide bond, sulfonic acid ester bond, sulfonic acid amide bond, carbonyl bond, carbonate bond, or carbamate bond. L B This is a divalent linking group represented by the following general formula (q1) or (q2), or a hydrocarbylene group having 1 to 8 carbon atoms. [ka] In the general formula (q1), m1 is an integer between 1 and 4. 1 and R 2 Each of these is independently a hydrogen atom, a halogen atom other than a fluorine atom, a cyano group, a nitro group, a hydroxyl group, an alkoxy group, an alkylthio group, an amino group, a mercapto group, a pentafluorosulfanil group, or a C1-C20 hydrocarbyl group, hydrocarbyloxy group, or hydrocarbylthio group, which may contain a heteroatom, and at least one of them is an electron-withdrawing group. [ka] In the general formula (q2), m2 is either 0 or 1. m3 is an integer from 1 to 4 when m2 is 0, and an integer from 1 to 6 when m2 is 1. m4 is an integer from 0 to 3 when m2 is 0, and an integer from 0 to 5 when m2 is 1. m3 + m4 is an integer from 1 to 4 when m2 is 0, and an integer from 1 to 6 when m2 is 1. R fm3 is a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms, or a pentafluorosulfanil group. When there are multiple m3s, each R f These may be identical or different from each other. 3 This is a C1-C20 hydrocarbyl group, hydrocarbyloxy group, or hydrocarbylthio group, which may contain a halogen atom other than a fluorine atom, a cyano group, a nitro group, a hydroxyl group, an alkoxy group, an alkylthio group, an amino group, a mercapto group, or a heteroatom. In general formulas (q1) and (q2), * represents L A The bond site is shown, and ** indicates the bond site with the sulfonate anion. Z + This is a sulfonium cation represented by the above general formula (Z-1) or an iodonium cation represented by the following general formula (Z-2).

[0289] Specific examples of the photoacid generator anion represented by formula (q) are listed below, but are not limited to these.

[0290] [ka]

[0291] When the chemically amplified resist composition of the present invention contains a quencher component (E), its content is preferably 0.001 to 12 parts by mass, and more preferably 0.01 to 8 parts by mass, per 80 parts by mass of the base polymer component (B). The inclusion of the (E) quencher facilitates the adjustment of the sensitivity of the resist film, suppresses acid diffusion in the resist film, improves resolution, suppresses sensitivity changes after exposure, reduces substrate and environmental dependence, and improves exposure margin and pattern profile. Furthermore, the addition of the quencher can also improve substrate adhesion. The (E) quencher may be used alone or in combination of two or more types.

[0292] [(G) Surfactants] The chemically amplified resist composition of the present invention may further contain a surfactant as component (G). The surfactant (G) is preferably a surfactant that is insoluble or sparingly soluble in water and soluble in an alkaline developer, or a surfactant that is insoluble or sparingly soluble in both water and an alkaline developer. Such surfactants can be found by referring to the (S) defined components described in Japanese Patent Publication No. 2010-215608 and Japanese Patent Publication No. 2011-16746.

[0293] As surfactants that are insoluble or poorly soluble in water and alkaline developer, among the surfactants described in the above publication, FC-4430 (manufactured by 3M), Surflon® S-381 (manufactured by AGC Seimi Chemical Co., Ltd.), Orfin® E1004 (manufactured by Nisshin Chemical Industry Co., Ltd.), KH-20, KH-30 (manufactured by AGC Seimi Chemical Co., Ltd.), and oxetane ring-opening polymers represented by the following formula (surf-1) are preferred.

[0294] [ka]

[0295] Here, R, Rf, A, B, C, m, and n apply only to formula (surf-1), notwithstanding the preceding description. R is a divalent to tetravalent aliphatic group having 2 to 5 carbon atoms. Examples of such aliphatic groups include the divalent ethylene group, 1,2-propanediyl group, 1,4-butanediyl group, 2,2-dimethyl-1,3-propanediyl group, and 1,5-pentanediyl group, while examples of trivalent or tetravalent groups include those listed below.

[0296] [ka] (In the formula, the dashed lines represent bonds, which are substructures derived from glycerol, trimethylolethane, trimethylolpropane, and pentaerythritol, respectively.)

[0297] Among these, the 1,4-butanediyl group or the 2,2-dimethyl-1,3-propanediyl group are preferred.

[0298] In formula (surf-1), Rf is a trifluoromethyl group or a pentafluoroethyl group, preferably a trifluoromethyl group. m is an integer from 0 to 3. n is an integer from 1 to 4. The sum of m and n is the valence of R, an integer from 2 to 4. A is 1. B is an integer from 2 to 25, preferably an integer from 4 to 20. C is an integer from 0 to 10, preferably 0 or 1. Furthermore, the arrangement of each constituent unit in formula (surf-1) is not predetermined; they may be bonded in a block-like manner or randomly. For details on the production of partially fluorinated oxetane ring-opening polymer surfactants, please refer to U.S. Patent No. 5,650,483, etc.

[0299] [Pattern formation method] The pattern formation method of the present invention includes the steps of forming a resist film on a substrate using the above-mentioned chemically amplified resist composition, exposing the resist film with high-energy rays, and developing the exposed resist film using a developer.

[0300] As the substrate, for example, substrates for integrated circuit manufacturing (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflective coatings, etc.) or substrates for mask circuit manufacturing (Cr, CrO, CrON, MoSi2, SiO2, etc.) can be used.

[0301] The resist film can be formed by, for example, applying the chemically amplified resist composition of the present invention onto a substrate to a thickness of 0.05 to 2 μm using a method such as spin coating, and then pre-baking it on a hot plate at preferably 60 to 150°C for 1 to 10 minutes, more preferably 80 to 140°C for 1 to 5 minutes.

[0302] High-energy beams used for exposure of resist films include KrF excimer lasers, ArF excimer lasers, EUV and EB with wavelengths of 3 to 15 nm. When using KrF excimer laser light, ArF excimer laser light, or EUV, exposure is performed using a mask to form the desired pattern, with an exposure dose of preferably 1 to 200 mJ / cm². 2 More preferably 10-100 mJ / cm² 2 This can be done by irradiating in such a manner. When using electroluminescence (EB), the exposure amount is preferably 0.1 to 100 μC / cm², either using a mask to form the desired pattern or directly. 2 More preferably 0.5 to 50 μC / cm² 2 Irradiate in such a way that it results in the following.

[0303] In addition to conventional exposure methods, immersion exposure can also be performed by interposing a liquid with a refractive index of 1.0 or higher, particularly water, between the resist film and the projection lens. In this case, a protective film insoluble in water can also be used.

[0304] The aforementioned water-insoluble protective film is used to prevent leaching from the resist film and to improve the water-repellent properties of the film surface, and there are two main types. One is an organic solvent-removable type that requires removal before alkaline aqueous solution development using an organic solvent that does not dissolve the resist film, and the other is an alkaline aqueous solution-soluble type that is soluble in alkaline developer and removes the protective film along with the soluble parts of the resist film. The latter is particularly preferably based on a polymer having a 1,1,1,3,3,3-hexafluoro-2-propanol residue that is insoluble in water and soluble in alkaline developer, and dissolved in an alcohol-based solvent having 4 or more carbon atoms, an ether-based solvent having 8 to 12 carbon atoms, or a mixture thereof. Alternatively, the aforementioned water-insoluble and alkaline developer-soluble surfactant can be dissolved in an alcohol-based solvent having 4 or more carbon atoms, an ether-based solvent having 8 to 12 carbon atoms, or a mixture thereof.

[0305] Post-exposure baking (PEB) may be performed after exposure. PEB can be performed, for example, by heating on a hot plate, preferably at 60-150°C for 1-5 minutes, more preferably at 80-140°C for 1-3 minutes.

[0306] Development can be carried out, for example, by using a developer solution that is preferably an alkaline aqueous solution such as tetramethylammonium hydroxide (TMAH) in an amount of 0.1 to 5% by mass, more preferably 2 to 3% by mass, and developing by a conventional method such as dipping, puddling, or spraying for preferably 0.1 to 3 minutes, more preferably 0.5 to 2 minutes. This forms the desired pattern on the substrate.

[0307] Furthermore, after the resist film is formed, a rinsing with pure water phosphorus may be performed to extract acid generators from the film surface or to wash away particles, or a rinse may be performed to remove any water remaining on the film after exposure.

[0308] Furthermore, in the pattern formation method of the present invention, negative tone development can also be performed by using an organic solvent instead of the alkaline aqueous solution as the developer to dissolve the unexposed areas.

[0309] This organic solvent development uses the following as developers: 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclohexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, phenyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, methyl valerate, pentene Methyl benzoate, methyl crotate, ethyl crotate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, benzyl acetate, methyl phenylacetate, benzyl formate, phenylethyl formate, methyl 3-phenylpropionate, benzyl propionate, ethyl phenylacetate, 2-phenylethyl acetate, etc. can be used. These organic solvents may be used individually or in mixtures of two or more. [Examples]

[0310] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0311] [1] Synthesis of fluorine atom-containing polymers The compound monomer represented by the following formula was synthesized.

[0312] [ka]

[0313] [ka]

[0314] [ka]

[0315] [ka]

[0316] Synthesis of monomer D1-1 [ka]

[0317] (1) Synthesis of intermediate fluorinated alcohols Under a nitrogen atmosphere, 121 g of fluorinated acetone, 95 g of pyridine, and 23 g of acetaldehyde were added to a reaction vessel and stirred at room temperature. The reaction vessel was heated to 70°C and stirred overnight. After maturation, water was added to stop the reaction, and the concentrate obtained after a normal aqueous work-up was purified by distillation to obtain 86 g of the intermediate fluorinated alcohol (yield 70%).

[0318] (2) Synthesis of monomer D1-1 Under a nitrogen atmosphere, 86 g of fluorinated alcohol intermediate, 54 g of methacrylic anhydride, and 8 g of methanesulfonic acid were added. The reaction vessel was heated to 60°C and stirred overnight. After maturation, water was added to stop the reaction, and a normal aqueous work-up was performed. The mixture was then concentrated to obtain 94 g of monomer D1-1 (yield 86%).

[0319] Synthesis of monomers D1-2 to D1-7 Monomers D1-2 to D1-7 were synthesized using corresponding raw materials and known organic synthesis reactions.

[0320] Synthesis of monomer D2-4 [ka]

[0321] (1) Synthesis of monomer D2-4 Under a nitrogen atmosphere, 25 g of adamantyl alcohol derivative, 25 g of pyridine, and 75 g of chlorodifluoroacetic anhydride were added to a reaction vessel and stirred in 120 g of toluene. After maturation, water was added to stop the reaction, and the concentrate obtained after a normal aqueous work-up was purified by distillation to obtain 35 g of monomer D2-4 (yield 82%).

[0322] Synthesis of monomers D2-1 to D2-3 and D2-5 to D2-11 Monomers D2-1 to D2-3 and D2-5 to D2-11 were synthesized using corresponding raw materials and known organic synthesis reactions.

[0323] Synthesis of monomer D3-5 [ka]

[0324] (1) Synthesis of monomer D3-5 Under a nitrogen atmosphere, 15 g of vinylbenzoic acid, 20 g of triethylamine, and 24 g of 1,3-dichlorotetrafluoroisopropanol were added to a reaction vessel and stirred in 120 g of dichloromethane. After maturation, water was added to stop the reaction, and the concentrate obtained after a normal aqueous work-up was purified by distillation to obtain 26 g of monomer D3-5 (yield 80%).

[0325] Synthesis of monomers D3-1~D3-4, D3-6, and D3-7 Monomers D3-1 to D3-4, D3-6, and D3-7 were synthesized using corresponding raw materials and known organic synthesis reactions.

[0326] [2] Synthesis of fluorine atom-containing polymers The polymer used in the chemically amplified resist composition of the present invention was synthesized by the method described below. The Mw of the obtained polymer was measured as a polystyrene equivalent value by GPC using THF as the solvent.

[0327] Synthesis of polymer SF-17 Under a nitrogen atmosphere, monomer D2-4 (14.8g), monomer D4-1 (7.0g), monomer D5-3 (8.3g), pyridine (0.05g), and dimethyl 2,2'-azobisisobutyrate (1.52g) were dissolved in PGMEA (42g) to prepare a solution. This solution was added dropwise to PGMEA (14g), which had been stirred at 80°C under a nitrogen atmosphere, over 4 hours. After the addition was complete, the mixture was stirred for 2 hours while maintaining the 80°C temperature, cooled to room temperature, and then the reaction solution was added dropwise to a methanol / water = 9:1 solution (480g). The precipitated solid was filtered off, washed twice with a methanol / water = 9:1 solution (180g), filtered off the precipitated solid, and vacuum-dried at 50°C for 20 hours to obtain the polymer SF-17 shown below as a white powder. The yield was 22g, and the yield rate was 73%.

[0328] [ka]

[0329] Polymers SF-1 to SF-16, and SF-18 to SF-50 Polymers SF-1 to SF-50, shown in Tables 1 and 2, were manufactured using the same method as polymer SF-17, except that the types and mixing ratios of each monomer were changed.

[0330] [Table 1]

[0331] [Table 2]

[0332] The compound monomer represented by the following formula was used as a comparative monomer.

[0333] [ka]

[0334] [Table 3]

[0335] [3] Synthesis of base polymers The base polymer used in the chemically amplified resist composition of the present invention was synthesized by the method described below. The Mw of the obtained polymer was measured as a polystyrene equivalent value by GPC using THF as the solvent.

[0336] Synthesis of polymer P-1 Under a nitrogen atmosphere, α-methacrylateoxy-γ-butyrolactone (32.5 g), 3-hydroxyadamantyl methacrylate (12.9 g), 1-ethylcyclopentyl methacrylate (54.6 g), and dimethyl 2,2'-azobisisobutyrate (6.27 g) were dissolved in PGMEA (155 g) to prepare a solution. This solution was added dropwise over 5 hours to PGMEA (78 g) stirred at 80°C under a nitrogen atmosphere. After the addition was complete, the mixture was stirred for 2 hours while maintaining the 80°C temperature, cooled to room temperature, and then the reaction solution was added dropwise to methanol (2000 g). The precipitated solid was filtered off and vacuum-dried at 50°C for 20 hours to obtain polymer P-1 as a white powder. The yield was 82 g, and the yield rate was 82%. [ka]

[0337] Synthesis of polymer P-2 Polymer P-2, as shown below, was produced using the same method as in Synthesis Example 2-1, except that the type of monomer and the mixing ratio were changed. [ka]

[0338] [4] Preparation of chemically amplified resist compositions A predetermined component selected from a photoacid generator, base polymers P-1 and P-2, a quencher, and a fluorine atom-containing polymer was dissolved in a solvent containing 0.01% by mass of surfactant A (manufactured by Omnova) in the composition shown in the table below to prepare a solution. This solution was then filtered through a 0.2 μm Teflon® filter to prepare the chemically amplified resist compositions shown in the table below.

[0339] [Table 4]

[0340] [Table 5]

[0341] In Tables 4-5, the solvent, photoacid generators PAG-1 to PAG-10, and quenchers Q-1 to Q-4 are as follows:

[0342] • Solvent: PGMEA (Propylene glycol monomethyl ether acetate) GBL (γ-butyrolactone)

[0343] • Photoacid generators: PAG-1 to PAG-10 [ka]

[0344] • Quencher: Q-1~Q-4 [ka]

[0345] • Surfactant A: 3-methyl-3-(2,2,2-trifluoroethoxymethyl)oxetane-tetrahydrofuran-2,2-dimethyl-1,3-propanediol copolymer (manufactured by Omnova) [ka] a:(b+b'):(c+c')=1:4~7:0.01~1 (molar ratio) Mw=1500

[0346] [Examples 1-1 to 1-63, Comparative Examples 1-1 to 1-15] ArF lithography evaluation (1) Each resist composition was spin-coated onto a silicon substrate on which an anti-reflective film ARC-29A (manufactured by Nissan Chemical Industries, Ltd.) was deposited to a thickness of 87 nm. The resist was then baked at 100°C for 60 seconds using a hot plate to form a resist film with a thickness of 80 nm. An ArF excimer laser immersion scanner (ASML XT-1900Gi, NA=1.20, Dipole) was used to expose the resist film with a line-and-space pattern (LS pattern) with dimensions of 40 nm and a pitch of 80 nm on the wafer, by varying the exposure dose and focus (exposure dose pitch: 1 mJ / cm²). 2 The process was carried out while adjusting the focus pitch (0.025 μm). After exposure, PEB was performed at 95°C for 60 seconds. Water was used as the immersion solution. Subsequently, paddle development was performed with a 2.38 mass% TMAH aqueous solution for 30 seconds, rinsed with pure water, and spin-dried to obtain a positive-type LS pattern. The obtained LS pattern was observed using a Hitachi High-Tech Corporation measuring SEM (CG-5000), and the sensitivity and LWR were evaluated according to the method described below. The results are shown in Tables 6 and 7.

[0347] [Sensitivity evaluation] In terms of sensitivity, the optimal exposure dose Eop(mJ / cm²) for obtaining an LS pattern with a pitch of 80nm and a line width of 40nm is required. 2 We calculated this value and defined it as the sensitivity.

[0348] [LWR rating] For each line in the obtained LS pattern, the line width was measured at 32 points, and 11 line widths were measured from a single SEM image. The variation in these line widths was defined as the LWR. A smaller value indicates better LWR.

[0349] [Maximum CD rating for line patterns] The line dimensions for each exposure at the optimal focus of the aforementioned LS pattern were measured at 10 points along the longitudinal direction. The maximum CD at which the line patterns resolve without bridging was calculated. A larger value indicates higher suppression of bridging defects. If bridging occurs around the target CD of 40nm, it is labeled as "Target".

[0350] [Post-SB RCA evaluation] The resist composition was baked at 100°C for 60 seconds using a hot plate to form a resist film with a thickness of 80 nm. The wafer on which the resist film was formed was kept horizontal, and 50 μL of pure water was dropped onto it to form a droplet. Then, the wafer was gradually tilted using a Drop Master 500 tilt-type contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.) to determine the receding contact angle at which the droplet began to roll off.

[0351] [Evaluation of the number of development defects] After performing checker flag exposure on the entire wafer in 20 mm square areas, alternating between exposed and unexposed areas using an open frame, PEB (Photobleached Embossing) was performed, followed by development in a 2.38% TMAH aqueous solution for 60 seconds. The number of blob defects in the unexposed areas was measured using a defect inspection device, WinWin-50-1200 (manufactured by Tokyo Seimitsu Co., Ltd.), with a pixel size of 0.125 μm.

[0352] [Table 6]

[0353] [Table 7]

[0354] As shown in Tables 6 and 7, in Examples 1-1 to 1-63, by using a fluorine atom-containing polymer containing repeating units having a structure represented by formula (d0) (difluorohalogen units) and a base-dissociable group, it was possible to achieve both good lithography performance, good water repellency, and development defect suppression ability. On the other hand, in Comparative Examples 1-1 to 1-15, which used a fluorine atom-containing polymer that did not contain repeating units having a structure represented by formula (d0) (difluorohalogen units) and a base-dissociable group, it was not possible to achieve both good lithography performance, water repellency, and development defect suppression ability.

[0355] [Examples 2-1 to 2-50, Comparative Examples 2-1 to 2-15] ArF lithography evaluation (2) Each resist composition was spin-coated onto a substrate for a tri-layer process, which consisted of a silicon substrate on which Shin-Etsu Chemical Co., Ltd.'s spin-on carbon film ODL-180 (carbon content 80% by mass) was deposited to a thickness of 180 nm, and then a silicon-containing spin-on hard mask SHB-A941 (silicon content 43% by mass) was deposited on top of that to a thickness of 35 nm. The resist film was then baked at 100°C for 60 seconds using a hot plate to form a resist film with a thickness of 100 nm. The resist film was then exposed to a contact hole (CH) pattern with a wafer dimension of 52 nm and a pitch of 104 nm using an ArF excimer laser immersion scanner (ASML XT-1900Gi, NA=1.35, 3 / 4 Annular, XY polarization), by varying the exposure dose and focus (exposure dose pitch: 1 mJ / cm²). 2 The process was carried out while adjusting the focus pitch (0.025 μm). After exposure, PEB was performed at 95°C for 60 seconds. Water was used as the immersion solution. Subsequently, paddle development was performed with n-butyl acetate for 30 seconds, rinsed with 4-methyl-2-pentanol, and spin-dried to obtain a negative-type pattern, the CH pattern. The obtained CH pattern was observed using a Hitachi High-Tech Corporation measuring SEM (CG-5000), and the sensitivity, CDU, and MEF were evaluated according to the method described below. The results are shown in Tables 8 and 9.

[0356] [Sensitivity evaluation] In terms of sensitivity, the optimal exposure dose Eop(mJ / cm²) for obtaining a CH pattern with a hole pitch of 104nm and a hole diameter of 52nm is required. 2 We calculated this value and defined it as the sensitivity.

[0357] [CDU Rating] The CH patterns obtained by irradiation with Eop were measured at 10 locations within the same exposure shot (9 CH patterns per location), and the CDU was calculated as three times the standard deviation (σ) (3σ) from these results. The smaller this value, the better the CDU of the CH pattern.

[0358] [Post-SB RCA evaluation] The resist composition was baked at 100°C for 60 seconds using a hot plate to form a resist film with a thickness of 100 nm. The wafer on which the resist film was formed was kept horizontal, and 50 μL of pure water was dropped onto it to form a droplet. Then, the wafer was gradually tilted using a Drop Master 500 tilt-type contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.) to determine the receding contact angle at which the droplet began to roll off.

[0359] [Table 8]

[0360] [Table 9]

[0361] As shown in Tables 8 and 9, in Examples 2-1 to 2-50, by using a fluorine atom-containing polymer containing repeating units having a structure represented by formula (d0) (difluorohalogen units) and a base-dissociable group, it was possible to achieve both good lithography performance, good water repellency, and development defect suppression ability. On the other hand, in Comparative Examples 2-1 to 2-15, which used a fluorine atom-containing polymer that did not contain repeating units having a structure represented by formula (d0) (difluorohalogen units) and a base-dissociable group, it was not possible to achieve both good lithography performance, water repellency, and development defect suppression ability.

[0362] This specification includes the following inventions:

[0363] [1]: A chemically amplified resist composition characterized by containing (A) a photoacid generator, (B) a base polymer having an acid-unstable group, and (C) an organic solvent, and further containing (D) a fluorine atom-containing polymer having a repeating unit having a structure represented by the following formula (d0) and a base-dissociable group. [ka] (In the formula, X is a halogen atom other than a fluorine atom.)

[0364] [2]: The chemical amplification resist composition according to [1] above, wherein the (D) fluorine atom-containing polymer may contain repeating units represented by the following formula (D1), and contains at least one of the repeating units represented by the following formula (D2) and the repeating units represented by the following formula (D3). [ka] (In the formula, R B This is either a hydrogen atom or a methyl group. L is a C1-C10 hydrocarbylene group which may contain a single bond, a carbonyl group, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonamide bond, a carbonate bond, a carbamate bond, or a carbonyl group, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonamide bond, a carbonate bond, or a carbamate bond. 21 and R 22 Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. 23 This is a 1-20 carbon dioxide hydrocarbylene group which may contain single bonds or linear, branched, or cyclic heteroatoms. 23k This is a (k+1) valent organic group having 1 to 20 carbon atoms, which may contain single bonds or linear, branched, or cyclic heteroatoms. 24This includes a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, and an acyl group having 2 to 15 carbon atoms, and the hydrocarbyl group and acyl group may contain heteroatoms or acid-unstable groups. 24 When the group is a hydrocarbyl group, some of these -CH2- groups may be substituted with ether bonds or carbonyl groups. 25 This is a single-bonded, linear, or branched hydrocarbylene group having 1 to 5 carbon atoms. 25k A (k+1) valence organic group is a single-bonded, linear, or branched organic group with 1 to 5 carbon atoms. j is an integer between 1 and 2. k is an integer between 1 and 3. X is the same as described above.

[0365] [3]: The chemically amplified resist composition according to [2] above, characterized in that the (D) fluorine atom-containing polymer contains repeating units represented by the following formula (D4). [ka] (In the formula, R B This is the same as described above. R 26 R is a linear, branched, or cyclic hydrocarbylene group having 1 to 20 carbon atoms, which may contain single bonds, ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or urea bonds. 27 Each of these groups is independently a hydrogen atom, a C1-C12 hydrocarbyl group, a C1-C12 hydrocarbyloxy group, a C2-C12 hydrocarbyloxycarbonyl group, a C2-C12 hydrocarbylcarbonyloxy group, a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, or a nitro group, and may contain heteroatoms, acid-unstable groups, or base-unstable groups. o is either 0 or 1. When o is 0, m and n are independent integers between 0 and 5, and 0 ≤ m + n ≤ 5. When o is 1, m and n are independent integers between 0 and 7, and 0 ≤ m + n ≤ 7.

[0366] [4]: The chemically amplified resist composition according to [2] or [3] above, characterized in that the repeating unit (D2) is represented by the following formula (D2-1). [ka] (In the formula, R B , R 25 (X and k are the same as above.)

[0367] [5]: The chemical amplification resist composition according to [4] above, characterized in that the (D) fluorine atom-containing polymer comprises a repeating unit represented by formula (D2-1) and a repeating unit represented by the following formula (D4-1). [ka] (In the formula, R B This is the same as above. R 26 R is a linear, branched, or cyclic hydrocarbylene group having 1 to 20 carbon atoms, which may contain single bonds, ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or urea bonds. 27 Each of these groups is independently a hydrogen atom, a C1-C12 hydrocarbyl group, a C1-C12 hydrocarbyloxy group, a C2-C12 hydrocarbyloxycarbonyl group, a C2-C12 hydrocarbylcarbonyloxy group, a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, or a nitro group, and may contain heteroatoms, acid-unstable groups, or base-unstable groups. m is an integer of 4 or 5, where n=1 when m=4 and n=0 when m=5.

[0368] [6]: The chemically amplified resist composition according to any one of [1] to [5] above, characterized in that the content of the (D) fluorine atom-containing polymer is 0.1 to 20 parts by mass with respect to 80 parts by mass of the (B) base polymer.

[0369] [7]: The chemically amplified resist composition according to any one of [1] to [6] above, characterized in that the (B) base polymer includes repeating units having an acid-unstable group represented by the following formula (B1). [ka] (In the formula, R A R is a hydrogen atom or a methyl group. AL It is an acid-unstable group.

[0370] [8]: The chemically amplified resist composition according to any one of [1] to [7] above, characterized in that the (B) base polymer comprises at least one selected from repeating units represented by the following formula (B2), repeating units represented by the following formula (B3), and repeating units represented by the following formula (B4). [ka] (In the formula, R A R is a hydrogen atom or a methyl group. 11 and R 12 Each of these is independently either a hydrogen atom or a hydroxyl group. 13 R is a substituent having a lactone structure or a substituent having a sultone structure. 14 (This is a hydrogen atom, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or a monovalent fluoroalcohol-containing substituent having 1 to 15 carbon atoms.)

[0371] [9]: The chemical amplification resist composition according to any one of [1] to [8] above, characterized in that the (A) photoacid generator does not contain a "fully fluorinated methyl group" or a "fully fluorinated methylene group".

[0372]

[10] : The chemical amplification resist composition according to [9] above, characterized in that the (A) photoacid generator is represented by the following formula (a). [ka] [ka] [ka] [In the formula, R is a hydrocarbyl group having 1 to 50 carbon atoms, which may be substituted with a heteroatom, and L is a divalent linking group represented by formula (a1) or (a2). In equation (a1), m1 is an integer between 1 and 4. 1 and R 2 Each of these is independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxyl group, an alkoxy group, an alkylthio group, an amino group, a mercapto group, a pentafluorosulfanyl group, or a C1-C20 hydrocarbyl group, hydrocarbyloxy group, or hydrocarbylthio group, which may contain a heteroatom, and at least one of them is an electron-withdrawing group. In equation (a2), m2 is an integer between 0 and 1. m3 is between 0 and 4 when m2 is 0, and between 0 and 6 when m2 is 1. m4 is between 0 and 4 when m2 is 0, and between 0 and 6 when m2 is 1. However, when m2 is 0, 1 ≤ m3 + m4 ≤ 4, and when m2 is 1, 1 ≤ m3 + m4 ≤ 6. R f R is a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms, or a pentafluorosulfanil group. When there are multiple m3s, each R f These may be identical or different from each other. 3 This is a C1-C20 hydrocarbyl group, hydrocarbyloxy group, or hydrocarbylthio group, which may contain halogen atoms other than fluorine atoms, cyano groups, nitro groups, hydroxyl groups, alkoxy groups, alkylthio groups, amino groups, mercapto groups, or heteroatoms. However, when m3 is 0, R 3At least one of them is an electron-withdrawing group. In formulas (a1) and (a2), * indicates the binding site with R, and ** indicates the binding site with the sulfonate anion. Z + This is a sulfonium cation represented by the following formula (Z-1) or an iodonium cation represented by the following formula (Z-2). [ka] (In the formula, R ct1 ~R ct5 Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain a halogen atom or a heteroatom. ct1 and R ct2 However, they may bond with each other to form a ring with the sulfur atom to which they are bonded.

[0373]

[11] : The chemically amplified resist composition according to any one of [1] to

[10] above, further characterized by containing a surfactant.

[0374]

[12] : The chemically amplified resist composition according to any one of [1] to

[11] above, further characterized by comprising a quencher.

[0375]

[13] : A pattern forming method comprising the steps of forming a resist film on a substrate using a chemically amplified resist composition described in any of [1] to

[12] above, exposing the resist film with high-energy rays, and developing the exposed resist film using a developer.

[0376]

[14] : The pattern formation method according to

[13] above, characterized in that the high-energy beam is KrF excimer laser light, ArF excimer laser light, electron beam, or extreme ultraviolet light with a wavelength of 3 to 15 nm.

[0377]

[15] : The pattern forming method according to

[13] or

[14] above, characterized in that, in the exposure step, water is inserted between the projection lens and the resist film, and exposure is performed with high-energy rays through a photomask.

[0378]

[16] : A fluorine atom-containing polymer characterized by containing repeating units having a structure represented by the following formula (d0) and a base-dissociable group. [ka] (In the formula, X is a halogen atom other than a fluorine atom.)

[0379]

[17] : The fluorine atom-containing polymer according to

[16] above, which may contain repeating units represented by the following formula (D1), and is characterized by containing at least one of the repeating units represented by the following formula (D2) and the following formula (D3). [ka] (In the formula, R B This is either a hydrogen atom or a methyl group. L is a C1-C10 hydrocarbylene group which may contain a single bond, a carbonyl group, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonamide bond, a carbonate bond, a carbamate bond, or a carbonyl group, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonamide bond, a carbonate bond, or a carbamate bond. 21 and R 22 Each of these is independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. 23 This is a 1-20 carbon dioxide hydrocarbylene group which may contain single bonds or linear, branched, or cyclic heteroatoms. 23k This is a (k+1) valent organic group having 1 to 20 carbon atoms, which may contain single bonds or linear, branched, or cyclic heteroatoms. 24This includes a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, and an acyl group having 2 to 15 carbon atoms, and the hydrocarbyl group and acyl group may contain heteroatoms or acid-unstable groups. 24 When the group is a hydrocarbyl group, some of these -CH2- groups may be substituted with ether bonds or carbonyl groups. 25 This is a single-bonded, linear, or branched hydrocarbylene group having 1 to 5 carbon atoms. 25k A (k+1) valence organic group is a single-bonded, linear, or branched organic group with 1 to 5 carbon atoms. j is an integer between 1 and 2. k is an integer between 1 and 3. X is the same as described above.

[0380]

[18] : The fluorine atom-containing polymer according to

[17] above, characterized in that it contains repeating units represented by the following formula (D4). [ka] (In the formula, R B This is the same as described above. R 26 R is a linear, branched, or cyclic hydrocarbylene group having 1 to 20 carbon atoms, which may contain single bonds, ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or urea bonds. 27 Each of these groups is independently a hydrogen atom, a C1-C12 hydrocarbyl group, a C1-C12 hydrocarbyloxy group, a C2-C12 hydrocarbyloxycarbonyl group, a C2-C12 hydrocarbylcarbonyloxy group, a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, or a nitro group, and may contain heteroatoms, acid-unstable groups, or base-unstable groups. o is either 0 or 1. When o is 0, m and n are independent integers between 0 and 5, and 0 ≤ m + n ≤ 5. When o is 1, m and n are independent integers between 0 and 7, and 0 ≤ m + n ≤ 7.

[0381]

[19] : The fluorine atom-containing polymer according to

[17] or

[18] above, characterized in that the repeating unit (D2) is represented by the following formula (D2-1). [ka] (In the formula, R B , R 25 (X and k are the same as above.)

[0382]

[20] : The fluorine atom-containing polymer according to

[19] above, characterized in that it includes a repeating unit represented by the above formula (D2-1) and a repeating unit represented by the following formula (D4-1). [ka] (In the formula, R B This is the same as above. R 26 R is a linear, branched, or cyclic hydrocarbylene group having 1 to 20 carbon atoms, which may contain single bonds, ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or urea bonds. 27 Each of these groups is independently a hydrogen atom, a C1-C12 hydrocarbyl group, a C1-C12 hydrocarbyloxy group, a C2-C12 hydrocarbyloxycarbonyl group, a C2-C12 hydrocarbylcarbonyloxy group, a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, or a nitro group, and may contain heteroatoms, acid-unstable groups, or base-unstable groups. m is an integer of 4 or 5, where n=1 when m=4 and n=0 when m=5.

[0383] It should be noted that the present invention is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of the present invention and achieves similar effects is included within the technical scope of the present invention.

Claims

1. (A) A photoacid generator, (B) a base polymer having an acid-unstable group, and (C) an organic solvent, and further, (D) a fluorine atom-containing polymer containing a repeating unit having a structure represented by the following formula (d0) and a base-dissociable group, The chemically amplified resist composition is characterized in that the (D) fluorine atom-containing polymer may contain repeating units represented by the following formula (D1), and contains at least one of the repeating units represented by the following formula (D2) and the following formula (D3). 【Chemistry 1】 (In the formula, X is a halogen atom other than a fluorine atom.) 【Chemistry 2】 (In the formula, R Ｂ This is either a hydrogen atom or a methyl group. L represents a single bond, a carbonyl group, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonamide bond, a carbonate bond, a carbamate bond, or a hydrocarbylene group having 1 to 10 carbon atoms which may optionally contain a carbonyl group, an ether bond, an ester bond, an amide bond, a sulfonic acid ester bond, a sulfonamide bond, a carbonate bond or a carbamate bond. R ２１ and R ２２ are each independently a hydrogen atom or a hydrocarbyl group having 1 to 10 carbon atoms. R ２３ represents a single bond or a hydrocarbylene group having 1 to 20 carbon atoms which may optionally contain a linear, branched or cyclic hetero atom. R ２３ｋ represents a single bond or a (k+1)-valent organic group having 1 to 20 carbon atoms which may optionally contain a linear, branched or cyclic hetero atom. R ２４ represents a hydrogen atom, a hydrocarbyl group having 1 to 15 carbon atoms, or an acyl group having 2 to 15 carbon atoms, wherein the hydrocarbyl group and the acyl group may optionally contain a hetero atom or an acid-labile group. R ２４ is a hydrocarbyl group, a part of -CH ２ - may be substituted with an ether bond or a carbonyl group. R ２５ represents a single bond or a linear or branched hydrocarbylene group having 1 to 5 carbon atoms. R ２５ｋ represents a single bond or a linear or branched (k+1)-valent organic group having 1 to 5 carbon atoms. j is an integer between 1 and 2. k is an integer between 1 and 3. X is the same as described above. However, in the above formula (D3), when k is 2, R ２３ This is a 1-20 carbon-1 hydrocarbylene group which may contain linear, branched, or cyclic heteroatoms. However, in the above formula (D3), when k is 1, R ２３ This is a 1-20 carbon-1 hydrocarbylene group which may contain linear, branched, or cyclic heteroatoms, and may include an alicyclic group or an aromatic ring.

2. The chemical amplification resist composition according to claim 1, characterized in that the (D) fluorine atom-containing polymer contains repeating units represented by the following formula (D4). 【Transformation 3】 (In the formula, R Ｂ This is the same as described above. R ２６ R is a linear, branched, or cyclic hydrocarbylene group having 1 to 20 carbon atoms, which may contain single bonds, ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or urea bonds. ２７ Each of these groups is independently a hydrogen atom, a C1-C12 hydrocarbyl group, a C1-C12 hydrocarbyloxy group, a C2-C12 hydrocarbyloxycarbonyl group, a C2-C12 hydrocarbylcarbonyloxy group, a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, or a nitro group, and may contain heteroatoms, acid-unstable groups, or base-unstable groups. o is either 0 or 1. When o is 0, m and n are independent integers between 0 and 5, and 0 ≤ m + n ≤ 5. When o is 1, m and n are independent integers between 0 and 7, and 0 ≤ m + n ≤ 7.

3. The chemically amplified resist composition according to claim 1, characterized in that the repeating unit (D2) is represented by the following formula (D2-1). 【Chemistry 4】 (In the formula, R Ｂ , R ２５ (X and k are the same as above.)

4. The chemically amplified resist composition according to claim 3, characterized in that the (D) fluorine atom-containing polymer comprises a repeating unit represented by formula (D2-1) and a repeating unit represented by the following formula (D4-1). 【Transformation 5】 (In the formula, R Ｂ This is the same as above. R ２６ R is a linear, branched, or cyclic hydrocarbylene group having 1 to 20 carbon atoms, which may contain single bonds, ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or ester bonds, ether bonds, amide bonds, sulfonic acid ester bonds, urethane bonds, thiourethane bonds, or urea bonds. ２７ Each of these is independently a hydrogen atom, a C1-C12 hydrocarbyl group, a C1-C12 hydrocarbyloxy group, a C2-C12 hydrocarbyloxycarbonyl group, a C2-C12 hydrocarbylcarbonyloxy group, a hydroxyl group, a carboxyl group, a halogen atom, a cyano group, or a nitro group, and may contain heteroatoms, acid-unstable groups, or base-unstable groups. m is an integer of 4 or 5, where n=1 when m=4 and n=0 when m=5.

5. The chemically amplified resist composition according to claim 1, characterized in that the content of the (D) fluorine atom-containing polymer is 0.1 to 20 parts by mass with respect to 80 parts by mass of the (B) base polymer.

6. The chemically amplified resist composition according to claim 1, characterized in that the (B) base polymer includes repeating units having an acid-unstable group represented by the following formula (B1). 【Transformation 6】 (In the formula, R Ａ R is a hydrogen atom or a methyl group. ＡＬ It is an acid-unstable group.

7. The chemically amplified resist composition according to claim 6, characterized in that the (B) base polymer comprises at least one selected from the repeating units represented by the following formula (B2), the repeating units represented by the following formula (B3), and the repeating units represented by the following formula (B4). 【Transformation 7】 (In the formula, R Ａ R is a hydrogen atom or a methyl group. １１ and R １２ Each of these is independently either a hydrogen atom or a hydroxyl group. １３ R is a substituent having a lactone structure or a substituent having a sultone structure. １４ (This is a hydrogen atom, a fluorinated hydrocarbyl group having 1 to 15 carbon atoms, or a substituent containing a monovalent fluoroalcohol having 1 to 15 carbon atoms.)

8. The chemically amplified resist composition according to claim 1, characterized in that the (A) photoacid generator does not contain a "fully fluorinated methyl group" or a "fully fluorinated methylene group".

9. The chemically amplified resist composition according to claim 8, characterized in that the (A) photoacid generator is represented by the following formula (a). 【Transformation 8】 【Chemistry 9】 【Chemistry 10】 [In the formula, R is a 1-50 carbon hydrocarbyl group which may be substituted with a heteroatom, and L is a divalent linking group represented by formula (a1) or (a2). In equation (a1), m1 is an integer between 1 and 4. １ and R ２ Each of these is independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, a hydroxyl group, an alkoxy group, an alkylthio group, an amino group, a mercapto group, a pentafluorosulfanyl group, or a C1-C20 hydrocarbyl group, hydrocarbyloxy group, or hydrocarbylthio group, which may contain a heteroatom, and at least one of them is an electron-withdrawing group. In equation (a2), m2 is an integer between 0 and 1. m3 is between 0 and 4 when m2 is 0, and between 0 and 6 when m2 is 1. m4 is between 0 and 4 when m2 is 0, and between 0 and 6 when m2 is 1. However, when m2 is 0, 1 ≤ m3 + m4 ≤ 4, and when m2 is 1, 1 ≤ m3 + m4 ≤ 6. R ｆ R is a fluorine atom, a fluorinated saturated hydrocarbyl group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbyloxy group having 1 to 6 carbon atoms, a fluorinated saturated hydrocarbylthio group having 1 to 6 carbon atoms, or a pentafluorosulfanil group. When there are multiple m3s, each R ｆ These may be identical or different. ３ This is a C1-C20 hydrocarbyl group, hydrocarbyloxy group, or hydrocarbylthio group, which may contain halogen atoms other than fluorine atoms, cyano groups, nitro groups, hydroxyl groups, alkoxy groups, alkylthio groups, amino groups, mercapto groups, or heteroatoms. However, when m3 is 0, R ３ At least one of them is an electron-withdrawing group. In formulas (a1) and (a2), * indicates the binding site with R, and ** indicates the binding site with the sulfonate anion. Z ＋ This is a sulfonium cation represented by the following formula (Z-1) or an iodonium cation represented by the following formula (Z-2). 【Chemistry 11】 (In the formula, R ｃｔ１ ~R ｃｔ５ Each of these is independently a hydrocarbyl group having 1 to 30 carbon atoms, which may contain a halogen atom or a heteroatom. Also, R ｃｔ１ and R ｃｔ２ However, they may bond with each other to form a ring with the sulfur atom to which they are bonded.

10. Furthermore, the chemically amplified resist composition according to claim 1, characterized in that it further contains a surfactant.

11. Furthermore, the chemically amplified resist composition according to claim 1, characterized in that it further contains a quencher.

12. A pattern forming method characterized by comprising the steps of: forming a resist film on a substrate using a chemically amplified resist composition according to any one of claims 1 to 11; exposing the resist film with high-energy rays; and developing the exposed resist film using a developer.

13. The pattern formation method according to claim 12, characterized in that the high-energy beam is KrF excimer laser light, ArF excimer laser light, an electron beam, or extreme ultraviolet light with a wavelength of 3 to 15 nm.

14. The pattern forming method according to claim 12, characterized in that, in the exposure step, water is inserted between the projection lens and the resist film, and exposure is performed with high-energy rays through a photomask.

Images