Resist material and pattern forming method

Abstract

The invention relates to a resist material and a pattern forming method. The present invention addresses the problem of providing: a resist material which has small edge roughness and dimensional variation, excellent resolution, and good heat resistance; and a pattern forming method. [Solution] A resist material containing a base polymer (P) containing a repeating unit (A) containing a reactive group represented by formula (a1) or (a2) and a repeating unit (B) having an acid-decomposable group, a crosslinking agent having a structure represented by formula (1), a thermal acid generator, a photodecomposable quenching agent represented by formula (2), and an organic solvent. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a resist material and a pattern forming method. Background Art

[0002] With the high integration and high speed of LSI, the miniaturization of pattern rules is progressing rapidly. As the high-speed communication of 5G and the popularization of artificial intelligence (AI) are progressing, high-performance devices are needed to process them. As for the most advanced miniaturization technology, mass production of 5nm node devices using extreme ultraviolet (EUV) lithography with a wavelength of 13.5nm is underway. Furthermore, discussions on the use of EUV lithography in the next-generation 3nm node and the next-generation 2nm node devices are also underway.

[0003] In photolithography using DUV light sources, namely KrF and ArF excimer lasers, the acid generated by the photosensitive agent due to exposure is used as a catalyst to cause a reaction of the base polymer resin, thereby changing the solubility in the developer. Chemically amplified resists achieve high-sensitivity and high-resolution lithography, and are driving miniaturization as the main resist used in actual production steps.

[0004] Even in the next generation of lithography such as EUV, chemically amplified resists are still being widely explored and commercialized. On the other hand, with the miniaturization, the demand for improved resist performance is further increasing, especially the suppression of the deviation of the resist pattern size (LWR: line width roughness) and the improvement of resolution. The factors of LWR and resolution in chemically amplified resists include the diffusion length of the generated acid, the molecular weight of the base polymer, and the characteristics of the curve of the change of the dissolution rate to the exposure amount (dissolution contrast).

[0005] In order to suppress the diffusion of the acid generated in the exposed part toward the unexposed part, the addition of an acid diffusion control agent is effective. In addition, in order to suppress the diffusion of substances in the post-exposure baking (PEB: post-exposure baking) step, it is effective to increase the glass transition point (Tg) of the resist film. By increasing the molecular weight of the base polymer, Tg can be increased, but on the other hand, there is a problem of deterioration of roughness due to the increase of dissolved units during the development process. In order to solve such problems, some people have tried to increase the molecular weight of the polymer by acid-degradable cross-linking groups. Patent document 1 discloses a cross-linked polymer obtained by reacting a unit having a carboxyl group or a hydroxyl group with a divinyl ether unit. On the other hand, the molecular weight of the cross-linked polymer generated by the cross-linking of polymer chains becomes very large. If it is stored for a long time in the form of a resist solution, the polymers will aggregate with each other, resulting in an increase in the number of defects. Patent document 2 discloses a resist material containing a polymer having a reactive site and a monomer cross-linking agent. However, in the firing step after coating on the substrate, there is a problem that the cross-linking reaction between the cross-linking agent and the polymer does not proceed sufficiently, and the residual monomer components have an adverse effect on the photolithography performance.

[0006] Prior art literature

[0007] Patent Literature

[0008] [Patent Document 1] Japanese Patent No. 5562651

[0009] [Patent Document 2] International Publication No. WO2018 / 079449 Summary of the invention

[0010] [Problems to be solved by the invention]

[0011] Positive resists containing crosslinking agents undergo crosslinking reactions in the pre-bake step after resist coating to increase the molecular weight, and decompose in the PEB step after exposure to reduce the molecular weight. That is, a resist film with a high molecular weight in the unexposed part and a low molecular weight in the exposed part is formed, and the dissolution contrast can be improved.

[0012] However, in the conventional resist containing a crosslinking agent, the crosslinking reaction does not proceed sufficiently during the firing step, and a large amount of unreacted crosslinking agent components remain, which may adversely affect the photolithography performance.

[0013] The present invention is made in view of the above situation, and an object of the present invention is to provide a resist material having small edge roughness, small dimensional deviation, excellent resolution, and good heat resistance, and a pattern forming method.

[0014] [Methods to solve the problem]

[0015] In order to solve the above-mentioned problems, the present invention provides a resist material comprising:

[0016] A base polymer (P) comprising a repeating unit (A) containing a reactive group represented by the following formula (a1) or (a2) and a repeating unit (B) having an acid-decomposable group,

[0017] A cross-linking agent having a structure represented by the following formula (1),

[0018] Thermal acid generators,

[0019] A photodegradable quencher represented by the following formula (2), and

[0020] Organic solvents,

[0021] [Chemistry 1]

[0022]

[0023] In the formula, R A are each independently a hydrogen atom or a methyl group, Y a1 , Y a2 Each independently represents a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 14 carbon atoms and having an ester bond, an ether bond, an amide bond or a lactone ring, a1 is a hydrogen atom, a fluorine atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, R a1 With Y a1 They may also be bonded to each other and to the carbon atoms on the aromatic rings to which they are bonded to form a ring, p is 1 or 2, q is an integer from 0 to 4, 1≤p+q≤5, r is 0 or 1,

[0024] [Chemistry 2]

[0025]

[0026] In the formula, R 1a is an organic group which may have a substituent, L 1 is a linking group selected from a single bond, an ester bond, and an ether bond, R 1b is a single bond or a divalent organic group, n is an integer from 2 to 4,

[0027] [Chemistry 3]

[0028]

[0029] R 21 ~R 23 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and R 21 , R 22 and R 23 Any two of them may be bonded to each other and form a ring together with the sulfur atom to which they are bonded, l is an integer from 0 to 4, R 2bis a halogen atom, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 18 carbon atoms which may have a substituent, an amino group which may have a substituent, or a phenyl group which may have a substituent, and when l is 2 or more, R 2b They can also be different from each other, L 2a is a single bond, an ester bond, or a divalent linking group having 1 to 8 carbon atoms, R 2a is a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms which may have a substituent, and R 2a With R 2b They may also be bonded to each other and to form a ring together with the carbon atoms to which they are bonded.

[0030] Such a resist material has small edge roughness and dimensional deviation, excellent resolution, and good heat resistance.

[0031] Furthermore, it is preferred that the base polymer (P) contains a repeating unit (C) having a structural site that is decomposed by irradiation with active light or radiation to generate an acid.

[0032] If this is done, the dissolution contrast between the exposed portion and the unexposed portion will be further improved.

[0033] In this case, the repeating unit (C) contained in the base polymer (P) is more preferably represented by the following formula (c).

[0034] [Chemistry 4]

[0035]

[0036] In the formula, R c1 is a hydrogen atom or a methyl group, Z 1 is a single bond or an ester bond, Z 2 is a single bond or a divalent organic group having 1 to 20 carbon atoms, and may contain an ester bond, an ether bond, a lactone ring, an amide bond, a sultone ring, or an iodine atom. c1 ~Rf c4 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of them contains a fluorine atom, R c2 ~R c4 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and R c2 , R c3 and R c4 Any two of them may be bonded to each other and form a ring together with the sulfur atom to which they are bonded.

[0037] As the repeating unit (C), such a structure is suitably used.

[0038] Furthermore, the repeating unit (B) contained in the base polymer (P) is preferably represented by the following formula (b).

[0039] [Chemistry 5]

[0040]

[0041] In the formula, R b is a hydrogen atom or a methyl group, L b is a single bond, a phenylene group, a naphthylene group, or a divalent linking group having 1 to 15 carbon atoms and having at least one of an ester bond, an ether bond, a lactone ring, an amide group, and a heteroatom, R AL It is an acid-labile group.

[0042] As the repeating unit (B), such a structure is suitably used.

[0043] The repeating unit (A) contained in the base polymer (P) is represented by the formula (a1) and is preferably contained in an amount of 30 mol% or more based on the total of the repeating units in the base polymer (P).

[0044] Such a base polymer (P) has a high reaction efficiency with a cross-linking agent, thereby obtaining excellent lithographic properties.

[0045] The present invention also provides a pattern forming method, comprising: forming a resist film on a substrate using the resist material, exposing the resist film to high-energy rays, and developing the exposed resist film using a developer.

[0046] By using such a pattern forming method, a pattern with small edge roughness, small dimensional deviation and excellent resolution can be obtained.

[0047] At this time, in the step of forming the resist film, the firing temperature is preferably set to 130° C. or higher.

[0048] When the firing temperature is set to 130° C. or higher, a weak acid is generated from the thermal acid generator, which acts as a catalyst, and the cross-linking reaction proceeds efficiently.

[0049] [Effects of the Invention]

[0050] The resist material (composition) of the present invention comprising a polymer containing a specific repeating unit, a specific cross-linking agent, a thermal acid generator, a specific sulfonium salt, and an organic solvent has small edge roughness and dimensional deviation, excellent resolution, and good heat resistance. Therefore, it has excellent characteristics and is extremely practical, and is particularly useful as a fine pattern forming material for a photomask used for ultra-LSI manufacturing or EB depiction, and a pattern forming material for EB or EUV lithography. The resist material of the present invention, for example, can not only be applied to the lithography in the formation of semiconductor circuits, but can also be applied to the formation of mask circuit patterns, micromachines, and thin film magnetic head circuit formation. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] [ Figure 1 ] A graph showing contrast curves of the resist films of Example 3-9 and Comparative Example 3-10. DETAILED DESCRIPTION

[0052] As described above, it is necessary to develop a resist material and a pattern forming method that have small edge roughness, small dimensional variation, excellent resolution, and good heat resistance.

[0053] As a result of repeated studies, the inventors of the present application have found that the above-mentioned problems can be solved by a resist composition containing a base polymer having a specific structural unit, a specific crosslinking agent, a thermal acid generator, and a sulfonium salt having a specific structure.

[0054] That is, the present invention is a resist material comprising: a base polymer (P) comprising a repeating unit (A) containing a reactive group represented by the following formula (a1) or (a2) and a repeating unit (B) having an acid-degradable group, a cross-linking agent having a structure represented by the following formula (1), a thermal acid generator, a photodegradable quencher represented by the following formula (2), and an organic solvent.

[0055] [Chemistry 6]

[0056]

[0057] In the formula, R A are each independently a hydrogen atom or a methyl group, Y a1 , Y a2 Each independently represents a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 14 carbon atoms and having an ester bond, an ether bond, an amide bond or a lactone ring, a1 is a hydrogen atom, a fluorine atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, R a1 With Y a1 They may also be bonded to each other and to the carbon atoms on the aromatic rings to which they are bonded to form a ring, p is 1 or 2, q is an integer from 0 to 4, 1≤p+q≤5, r is 0 or 1,

[0058] [Chemistry 7]

[0059]

[0060] In the formula, R 1a is an organic group which may have a substituent, L 1 is a linking group selected from a single bond, an ester bond, and an ether bond, R 1b is a single bond or a divalent organic group, n is an integer from 2 to 4,

[0061] [Chemistry 8]

[0062]

[0063] R 21 ~R 23 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and R 21 , R 22 and R 23 Any two of them may be bonded to each other and form a ring together with the sulfur atom to which they are bonded, l is an integer from 0 to 4, R 2b is a halogen atom, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 18 carbon atoms which may have a substituent, an amino group which may have a substituent, or a phenyl group which may have a substituent, and when l is 2 or more, R 2b They can also be different from each other, L 2a is a single bond, an ester bond, or a divalent linking group having 1 to 8 carbon atoms, R 2a is a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms which may have a substituent, and R 2a With R 2b They may also be bonded to each other and to form a ring together with the carbon atoms to which they are bonded.

[0064] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0065] [Resist material]

[0066] The resist material (composition) of the present invention comprises: a base polymer (P) comprising a repeating unit (A) having a reactive group and a repeating unit (B) having an acid-decomposable group, a specific crosslinking agent, a thermal acid generator, a specific sulfonium salt, and an organic solvent. When the resist is formed into a film on a wafer, a weak acid from the thermal acid generator is generated in the soft baking step. The base polymer is converted to a high molecular weight by an addition reaction between the vinyl ether portion of the crosslinking agent using the generated acid as a catalyst and the reactive group of the polymer. The crosslinked structure thus formed collapses and becomes low molecular weight due to the action of the strong acid component generated in the exposed part, so that not only the polarity of the base polymer changes, but also the dissolution contrast of the exposed part / unexposed part can be improved due to the effect of the molecular weight change.

[0067] [Base polymer (P)]

[0068] The base polymer of the present invention contains a repeating unit (A) having a reactive group and a repeating unit (B) having an acid-degradable group. Unit (A) contributes to a change in molecular weight, and unit (B) contributes to a change in polarity, so that a positive pattern with high resolution can be formed.

[0069] The base polymer (P) contains a repeating unit (A) represented by the following formula (a1) or (a2).

[0070] [Chemistry 9]

[0071]

[0072] In the formula, R A Each is independently a hydrogen atom or a methyl group. a1 , Y a2 Each R is independently a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 14 carbon atoms and having an ester bond, an ether bond, an amide bond or a lactone ring. a1 is a hydrogen atom, a fluorine atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, R a1 With Y a1 They may also be bonded to each other and to the carbon atoms on the aromatic ring to which they are bonded to form a ring. p is 1 or 2, q is an integer from 0 to 4, 1≤p+q≤5. r is 0 or 1.

[0073] Examples of the monomer that provides the repeating unit (a1) include the following, but are not limited thereto.

[0074] [Chemistry 10]

[0075]

[0076] [Chemistry 11]

[0077]

[0078] Examples of the monomer providing the repeating unit (a2) include the following, but are not limited thereto.

[0079] [Chemistry 12]

[0080]

[0081] The repeating unit (A) having a reactive group is preferably represented by the formula (a1), and is preferably contained in an amount of 30 mol% or more based on the total of the repeating units contained in the base polymer (P).

[0082] The content of the repeating unit represented by formula (a1) is preferably 30 mol% to 90 mol%, more preferably 35 mol% to 85 mol%, more preferably 40 mol% to 80 mol%, and more preferably 50 mol% to 70 mol%, relative to the base polymer (P).

[0083] When the content of the repeating unit (a1) is 30 mol% or more, the reaction efficiency with the crosslinking agent is sufficient, a large amount of unreacted crosslinking agent components will not remain in the system, and good photolithography performance will be provided. Therefore, it is preferred that the content of the repeating unit (a1) is 30 mol% or more.

[0084] The base polymer (P) contains a repeating unit (B) having an acid-decomposable group. Examples of the repeating unit (B) include a unit represented by the following formula (b).

[0085] [Chemistry 13]

[0086]

[0087] In formula (b), R b is a hydrogen atom or a methyl group. b R is a single bond, a phenylene group, a naphthylene group, or a divalent linking group having 1 to 15 carbon atoms and having at least one of an ester bond, an ether bond, a lactone ring, an acylamino group, and a heteroatom. AL It is an acid-labile group.

[0088] The monomers providing the repeating unit (B) include the following, but are not limited thereto.

[0089] [Chemistry 14]

[0090]

[0091] [Chemistry 15]

[0092]

[0093] Just R AL Examples of the acid-labile group represented by include groups represented by the following formulae (AL-1) to (AL-19), but the group is not limited thereto.

[0094] [Chemistry 16]

[0095]

[0096] In the formula, the dotted lines are atomic bonds.

[0097] In formulas (AL-1) to (AL-19), R L1 Each R is independently a saturated hydrocarbon group having 1 to 8 carbon atoms or an aryl group having 6 to 20 carbon atoms. L2 and R L4 Each R is independently a hydrogen atom or a saturated hydrocarbon group having 1 to 20 carbon atoms. L3 is an aryl group having 6 to 20 carbon atoms. The saturated hydrocarbon group may be linear, branched or cyclic. The aryl group is preferably a phenyl group. F is a fluorine atom or a trifluoromethyl group. a is an integer of 1-5.

[0098] The aforementioned base polymer (P) preferably contains a repeating unit (C) having a structural part that can be decomposed by irradiation with active light or radiation to generate an acid. The acid generated by the repeating unit (C) will decompose the acid-labile group and cross-linked structure possessed by the repeating unit (B). Thereby, the polarity change and low molecular weight of the exposed part of the resist film will occur, so the dissolution contrast with the unexposed part will be improved. It is believed that since the acid-generating unit is included in the polymer, in addition to suppressing the diffusion of the generated acid, it will also suppress the aggregation of the acid generators, so it has the effect of improving the uniformity of the acid concentration in the resist film.

[0099] The aforementioned repeating unit (C) is preferably represented by the following formula (c).

[0100] [Chemistry 17]

[0101]

[0102] In the formula, R c1 is a hydrogen atom or a methyl group. 1 is a single bond or an ester bond, Z 2 It is a single bond or a divalent organic group having 1 to 20 carbon atoms, and may contain an ester bond, an ether bond, a lactone ring, an amide bond, a sultone ring, or an iodine atom. c1 ~Rf c4 Each is independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of them contains a fluorine atom. c2 ~R c4 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. c2 , R c3 and R c4 Any two of them may be bonded to each other and form a ring together with the sulfur atom to which they are bonded.

[0103] In the formula, R c1 is a hydrogen atom or a methyl group. 1 is a single bond or an ester bond. 2It is a single bond or a divalent organic group having 1 to 20 carbon atoms, and may also contain an ester bond, an ether bond, a lactone ring, an amide bond, a sultone ring, or an iodine atom. It may be straight chain, branched chain, or cyclic. Specific examples thereof include methanediyl, ethane-1,1-diyl, ethane-1,2-diyl, propane-1,2-diyl, propane-1,3-diyl, propane-2,2-diyl, butane-1,2-diyl, butane-1,3-diyl, butane-1,4-diyl, butane-2,2-diyl, butane-2,3-diyl, 2-methyl Alkanediyl radicals having 1 to 20 carbon atoms, such as propane-1,3-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, and decane-1,10-diyl; cyclic saturated alkylene radicals having 3 to 20 carbon atoms, such as cyclopentanediyl, cyclohexanediyl, norbornanediyl, and adamantanediyl; and groups obtained by combining these radicals. c1 ~Rf c4 Each is independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of them contains a fluorine atom.

[0104] Furthermore, the repeating unit (C) preferably contains an iodine atom.

[0105] Examples of the anion of the monomer providing the repeating unit (c) include the following, but are not limited thereto.

[0106] [Chemistry 18]

[0107]

[0108] [Chemistry 19]

[0109]

[0110] [Chemistry 20]

[0111]

[0112] [Chemistry 21]

[0113]

[0114] [Chemistry 22]

[0115]

[0116] [Chemistry 23]

[0117]

[0118] In formula (c), R c2 ~R c4 Each is independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and is particularly a hydrocarbon group.c2 ~R c4 The hydrocarbon group having 1 to 20 carbon atoms represented by may be saturated or unsaturated, and may be straight-chain, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, undecyl, dodecanyl, tridecyl, tetradecyl, pentadecyl, heptadecanyl, octadecyl, nonadecanyl, and eicosyl; cyclic saturated hydrocarbon groups having 3 to 20 carbon atoms, such as cyclopropyl, cyclopentyl, cyclohexyl, cyclopropylmethyl, 4-methylcyclohexyl, cyclohexylmethyl, norbornyl, and adamantyl; alkenyl groups having 2 to 20 carbon atoms, such as vinyl, propenyl, butenyl, and hexenyl; Alkynyl groups having 2 to 20 carbon atoms, such as ethynyl, propynyl, and butynyl; cyclic unsaturated aliphatic hydrocarbon groups having 3 to 20 carbon atoms, such as cyclohexenyl and norbornenyl; aryl groups having 6 to 20 carbon atoms, such as phenyl, methylphenyl, ethylphenyl, n-propylphenyl, isopropylphenyl, n-butylphenyl, isobutylphenyl, sec-butylphenyl, tert-butylphenyl, naphthyl, methylnaphthyl, ethylnaphthyl, n-propylnaphthyl, isopropylnaphthyl, n-butylnaphthyl, isobutylnaphthyl, sec-butylnaphthyl, and tert-butylnaphthyl; aralkyl groups having 7 to 20 carbon atoms, such as benzyl and phenethyl; and groups obtained by combining these. Furthermore, part or all of the hydrogen atoms of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a halogen atom, and part of the -CH2- of the aforementioned hydrocarbon group may be substituted by a group containing a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom, resulting in a hydroxyl group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a carbonyl group, an ether bond, an ester bond, a sulfonate bond, a carbonate group, a lactone ring, a sultone ring, a carboxylic anhydride (-C(=O)-OC(=O)-), a haloalkyl group, and the like.

[0119] Again, R c2 With R c3 They may also be bonded to each other and form a ring together with the sulfur atom to which they are bonded. In this case, the following structure is preferred for the ring.

[0120] [Chemistry 24]

[0121]

[0122] In the formula, the dotted line is related to R c4 of atomic bonds.

[0123] Examples of the cation of the monomer providing the repeating unit (c) include the following, but are not limited thereto.

[0124] [Chemistry 25]

[0125]

[0126] [Chemistry 26]

[0127]

[0128] The repeating unit (B) is preferably contained in an amount of 10 mol% to 70 mol% based on the total amount of the repeating units contained in the base polymer (P). The repeating unit (C) is preferably contained in an amount of 0 mol% to 20 mol% based on the total amount of the repeating units contained in the base polymer (P).

[0129] The aforementioned base polymer may also contain repeating units other than the repeating units (A) to (C) (hereinafter, also referred to as repeating units (D). As the repeating unit (D), known ones used in the base polymer of the resist composition can be used, and specific examples thereof include (meth)acrylate units having a lactone structure, a hydroxyl group other than a phenolic hydroxyl group, an adhesive group such as a carboxyl group, and a (meth)acrylic acid unit.

[0130] In order to synthesize the above-mentioned base polymer, for example, a monomer providing the above-mentioned repeating unit may be added to an organic solvent, a radical polymerization initiator may be added, and the mixture may be heated to perform polymerization.

[0131] The polystyrene-equivalent weight average molecular weight (Mw) of the base polymer measured by gel permeation chromatography (GPC) using THF as a solvent is preferably 1,000 to 500,000, more preferably 2,000 to 30,000. If Mw is 1,000 or more, the resist material has excellent heat resistance, and if it is 500,000 or less, the alkali solubility does not decrease, and there is no situation where tailing phenomenon is easily generated after pattern formation.

[0132] Furthermore, when the molecular weight distribution (Mw / Mn) of the base polymer is 1.0 to 2.0, since low molecular weight and high molecular weight polymers do not exist, there is no concern about visible foreign matter on the pattern after exposure or deterioration of the shape of the pattern. As the pattern rules become finer, the influence of Mw and Mw / Mn tends to become greater. Therefore, in order to obtain a resist material suitable for fine pattern sizes, the Mw / Mn of the base polymer is preferably 1.0 to 2.0, especially 1.0 to 1.5.

[0133] In the resist material of the present invention, the amount of the base polymer (P) blended is not particularly limited, and may be, for example, 0.5 to 50 parts by mass, preferably 1 to 10 parts by mass, based on 100 parts by mass of the resist material.

[0134] [Photoacid generator]

[0135] The resist material of the present invention may further contain an additive photoacid generator. The acid generated by the photoacid generator in the present invention is a strong acid having the same strength as the acid generated by the repeating unit (C) of the base polymer (P), and acts on the acid-labile groups and cross-linked structures of the repeating unit (B), thereby contributing to the improvement of the solubility contrast.

[0136] As for the aforementioned acid generator, for example, compounds (photoacid generators) that generate acid by induction of active light or radiation can be cited. As for the photoacid generator, any compound that generates acid due to high-energy ray irradiation can be used, and it is preferably one that generates sulfonic acid, imidic acid or methide acid. As for the preferred photoacid generator, there are sulfonium salts, iodonium salts, sulfonyldiazomethane, N-sulfonyloxyimide, oxime-O-sulfonate acid generators, etc. As for specific examples of the photoacid generator, those described in paragraphs

[0122] to

[0142] of Japanese Patent Gazette No. 2008-111103 can be cited.

[0137] Examples of the anion portion of the photoacid generator include those having structures represented by the following formulae (2A) to (2D).

[0138] [Chemistry 27]

[0139]

[0140] In formula (2A), R fa is a hydrocarbon group having 1 to 40 carbon atoms which may contain a fluorine atom or a heteroatom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the following: 111 The hydrocarbon groups represented are the same as those exemplified above.

[0141] The anion represented by the formula (2A) is preferably represented by the following formula (2A').

[0142] [Chemistry 28]

[0143]

[0144] In formula (2A'), R HF is a hydrogen atom or a trifluoromethyl group, preferably a trifluoromethyl group. 111 It is a hydrocarbon group having 1 to 38 carbon atoms which may contain a hetero atom. The hetero atom is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc., and an oxygen atom is more preferred. The hydrocarbon group is preferably a hydrocarbon group having 6 to 30 carbon atoms from the viewpoint of obtaining a high resolution in fine pattern formation.

[0145] R 111The hydrocarbon group represented by may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include alkyl groups having 1 to 38 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl, heptyl, 2-ethylhexyl, nonyl, undecyl, tridecyl, pentadecyl, heptadecanyl, eicosenyl, etc.; cyclic saturated hydrocarbon groups having 3 to 38 carbon atoms, such as cyclopentyl, cyclohexyl, 1-adamantyl, 2-adamantyl, 1-adamantylmethyl, norbornyl, norbornylmethyl, tricyclodecanyl, tetracyclododecyl, tetracyclododecylmethyl, dicyclohexylmethyl, etc.; unsaturated aliphatic hydrocarbon groups having 2 to 38 carbon atoms, such as allyl and 3-cyclohexenyl, aryl groups having 6 to 38 carbon atoms, such as phenyl, 1-naphthyl, 2-naphthyl, etc.; aralkyl groups having 7 to 38 carbon atoms, such as benzyl and diphenylmethyl, etc.; groups obtained by combining these, etc.

[0146] In addition, part or all of the hydrogen atoms of the above groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and part of -CH2- of these groups may be substituted by groups containing heteroatoms such as oxygen atoms, sulfur atoms, and nitrogen atoms, and as a result, hydroxyl groups, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, cyano groups, nitro groups, carbonyl groups, ether bonds, ester bonds, sulfonate bonds, carbonate bonds, lactone rings, sultone rings, carboxylic anhydride, haloalkyl groups, etc. may be included. Examples of heteroatom-containing hydrocarbon groups include tetrahydrofuranyl, methoxymethyl, ethoxymethyl, methylthiomethyl, acetylaminomethyl, trifluoroethyl, (2-methoxyethoxy)methyl, acetoxymethyl, 2-carboxy-1-cyclohexyl, 2-oxopropyl, 4-oxo-1-adamantyl, and 3-oxocyclohexyl.

[0147] For the synthesis of the sulfonium salt containing the anion represented by formula (2A'), see Japanese Patent Publication No. 2007-145797, Japanese Patent Publication No. 2008-106045, Japanese Patent Publication No. 2009-7327, Japanese Patent Publication No. 2009-258695, etc. Also, the sulfonium salts described in Japanese Patent Publication No. 2010-215608, Japanese Patent Publication No. 2012-41320, Japanese Patent Publication No. 2012-106986, Japanese Patent Publication No. 2012-153644, etc. can also be preferably used.

[0148] Examples of the anion represented by formula (2A) include the same anions as exemplified for the anion represented by formula (1A) in JP-A-2018-197853.

[0149] In formula (2B), R fb1 and R fb2Each is independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the following: 111 The hydrocarbon groups represented by are the same as those exemplified above. fb1 and R fb2 It is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fb1 With R fb2 They can also bond to each other and to the groups to which they are bonded (-CF2-SO2-N - -SO2-CF2-) together to form a ring, at this time, R fb1 With R fb2 The groups obtained by bonding to each other are preferably fluorinated vinyl groups or fluorinated propenyl groups.

[0150] In formula (2C), R fc1 , R fc2 and R fc3 Each is independently a fluorine atom or a hydrocarbon group having 1 to 40 carbon atoms which may contain a hetero atom. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the following: 111 The hydrocarbon groups represented by are the same as those exemplified above. fc1 , R fc2 and R fc3 It is preferably a fluorine atom or a linear fluorinated alkyl group having 1 to 4 carbon atoms. fc1 With R fc2 They can also bond to each other and to the groups to which they are bonded (-CF2-SO2-C - -SO2-CF2-) together to form a ring, at this time, R fc1 With R fc2 The groups obtained by bonding to each other are preferably fluorinated vinyl groups or fluorinated propenyl groups.

[0151] In formula (2D), R fd is a hydrocarbon group having 1 to 40 carbon atoms which may contain heteroatoms. The hydrocarbon group may be saturated or unsaturated, and may be linear, branched, or cyclic. Specific examples thereof include the following: 111 The hydrocarbon groups represented are the same as those exemplified above.

[0152] For details on the synthesis of the sulfonium salt containing the anion represented by the formula (2D), see Japanese Patent Application Laid-Open Nos. 2010-215608 and 2014-133723.

[0153] Examples of the anion represented by formula (2D) include the same anions as exemplified for the anion represented by formula (1D) in JP-A-2018-197853.

[0154] Furthermore, the photoacid generator containing the anion represented by formula (1D) has no fluorine atom at the α position of the sulfonic acid group but has two trifluoromethyl groups at the β position, and therefore has sufficient acidity to cut off the acid-labile groups in the base polymer. Therefore, it can be used as a photoacid generator.

[0155] Examples of the cation portion of the photoacid generator include the same ones as exemplified for the sulfonium cation in the repeating unit (C).

[0156] The amount of the photoacid generator to be blended is not particularly limited. When blended, for example, it is preferably 1 to 50 parts by mass, more preferably 5 to 30 parts by mass, based on 80 parts by mass of the base polymer (P).

[0157] [Crosslinking agent]

[0158] The crosslinking agent in the present invention is one that undergoes an addition reaction with the carboxyl group or hydroxyl group of the repeating unit (A) of the base polymer (P). In the pre-baking step on the substrate, the molecular weight is greatly increased by crosslinking the base polymer, and the diffusion of the acid and the dissolution in the developer are suppressed. In addition, the crosslinking structure is decomposed by the strong acid component generated by exposure, and only the exposed part is reduced in molecular weight, so that the contrast with the unexposed part can be improved.

[0159] The cross-linking agent has a structure represented by the following formula (1).

[0160] [Chemistry 29]

[0161]

[0162] In the formula, R 1a It is an organic group which may have a substituent. 1 is a linking group selected from a single bond, an ester bond, and an ether bond. 1b is a single bond or a divalent organic group. n is an integer of 2-4.

[0163] Furthermore, in the above crosslinking agent, in formula (1), R 1a Those containing an aromatic hydrocarbon group are preferred.

[0164] In the above crosslinking agent, in the formula (1), n ​​is preferably an integer of 3 or more. 1 It is preferably one containing an ether bond. 1b Those containing an aliphatic hydrocarbon group are preferred.

[0165] Examples of the crosslinking agent represented by formula (1) include the following, but are not limited thereto.

[0166] [Chemistry 30]

[0167]

[0168] [Chemistry 31]

[0169]

[0170] The amount of the crosslinking agent to be blended is not particularly limited, but is preferably 1 to 30 parts by mass, more preferably 3 to 20 parts by mass, based on 80 parts by mass of the base polymer (P).

[0171] [Photodegradable Quencher]

[0172] The photodegradable quencher in the present invention is an organic salt composed of an organic weak acid anion and a sulfonium cation that produces an acid weaker than the repeating unit (C) in the base polymer (P). The anion of the weak acid undergoes salt exchange with the strong acid generated by exposure to form a weak acid and a strong acid-sulfonium cation salt. In this way, the strong acid generated in the exposed part is replaced by a weak acid, which inhibits the modification of the base polymer caused by the acid. On the other hand, for areas with a sufficient amount of exposure, the sulfonium cation after the salt exchange will also decompose to produce a strong acid, and the dissolution rate of the resist film in the developer will change, so a pattern can be formed.

[0173] The photodegradable quencher has a structure represented by the following formula (2).

[0174] [Chemistry 32]

[0175]

[0176] In the formula, R 21 ~R 23 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom. 21 , R 22 and R 23 Any two of R may be bonded to each other and form a ring together with the sulfur atom to which they are bonded. l is an integer from 0 to 4. 2b is a halogen atom, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 18 carbon atoms which may have a substituent, an amino group which may have a substituent, or a phenyl group which may have a substituent, and when l is 2 or more, R 2b They may also be different from each other. 2a is a single bond, an ester bond, or a divalent linking group having 1 to 8 carbon atoms. 2a is a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms which may have a substituent. 2a With R 2bThey may also be bonded to each other and to form a ring together with the carbon atoms to which they are bonded.

[0177] When the photodegradable quencher has a structure represented by formula (2), the diffusion of the strong acid generated in the exposed area can be suppressed. On the other hand, the generation of the weak acid by the thermal acid generator in the firing step of the resist film and the crosslinking reaction between the crosslinking agent and the polymer using the crosslinking agent as a catalyst are not hindered, so that the molecular weight can be increased efficiently.

[0178] Furthermore, the photodegradable quencher is preferably one having an iodine atom.

[0179] Furthermore, when the photodegradable quencher has a hydroxyl group, the base polymer and the quencher component are bonded via the crosslinking agent, so that diffusion of the quencher component can be suppressed.

[0180] The structure of the anion portion of the quencher may be exemplified by the following, but the structure is not limited thereto.

[0181] [Chemistry 33]

[0182]

[0183] [Chemistry 34]

[0184]

[0185] Examples of the cation portion of the photodegradable quencher include the same ones as exemplified for the sulfonium cation in the repeating unit (C).

[0186] The amount of the photodegradable quencher to be blended is not particularly limited, but is preferably 1 to 30 parts by mass, more preferably 5 to 25 parts by mass, based on 80 parts by mass of the base polymer (P).

[0187] [Thermal acid generator]

[0188] The resist material of the present invention contains a thermal acid generator to promote the crosslinking reaction on the substrate. The acid generated by the thermal acid generator is weaker than the acid generated by the photoacid generator, so the crosslinking structure and the acid-labile group will not be decomposed.

[0189] As the thermal acid generator, an onium salt composed of an organic weak acid anion, an ammonium cation, or an iodonium cation is preferably used.

[0190] Examples of the anion portion of the thermal acid generator include those having structures represented by the following formulae (4A) to (4C).

[0191] [Chemistry 35]

[0192]

[0193] In formula (4A), Rf 4a1 , Rf 4a2 are each independently a hydrogen atom, a fluorine atom, or a trifluoromethyl group. 4a1 It is an organic group which may have a substituent, and preferably contains an iodine atom. 4a is a connecting group selected from a single bond, an ester bond, and an ether bond. 4a2 It is a divalent organic group which may have a substituent.

[0194] In formula (4B), L 4b is a connecting group selected from a single bond, an ester bond, and an ether bond, and a single bond is preferred. 4b It is an organic group which may have a substituent, and is preferably an aromatic hydrocarbon group having an iodine atom.

[0195] In formula (4C), L 4c is a connecting group selected from a single bond, an ester bond, and an ether bond. 4c It is an organic group which may have a substituent, and an aliphatic hydrocarbon group is preferred.

[0196] The thermal acid generator preferably has a structure represented by the following formula (4).

[0197] [Chemistry 36]

[0198]

[0199] In the formula, R 41 L is an organic group which may also have an iodine atom. The organic group may also have a hydroxyl group, a trifluoromethyl group, other halogen atoms, a nitro group, an acylamino group, and an alkoxy group. 4 is a connecting group selected from a single bond, an ester bond, and an ether bond. 42 It is a divalent organic group. 41 ~Rf 42 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group. 43 ~R 45 It is an alkyl group having 1 to 2 carbon atoms.

[0200] Examples of the thermal acid generator include the following, but are not limited thereto.

[0201] [Chemistry 37]

[0202]

[0203] [Chemistry 38]

[0204]

[0205] [Chemistry 39]

[0206]

[0207] The amount of the thermal acid generator to be blended is not particularly limited, but is, for example, preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, based on 80 parts by mass of the base polymer (P).

[0208] [Organic solvents]

[0209] The resist material of the present invention contains an organic solvent, which is not particularly limited as long as the components contained in the resist material of the present invention can be dissolved. Examples of the organic solvent include ketones such as cyclohexanone, cyclopentanone, methyl-2-n-pentyl ketone, and 2-heptanone described in paragraphs

[0144] to

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

[0210] When the resist material of the present invention contains an organic solvent, its content is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass, relative to 80 parts by mass of the base polymer (P). The organic solvent may be used alone or in combination of two or more.

[0211] [Surfactant]

[0212] The resist material of the present invention may further include a surfactant. As for the aforementioned surfactant, those described in paragraphs

[0165] to

[0166] of Japanese Patent Publication No. 2008-111103 can be cited. By adding a surfactant, the coating property of the resist material can be further improved or controlled. When the resist material of the present invention contains a surfactant, its content is preferably 0.0001 to 10 parts by mass relative to 80 parts by mass of the base polymer (P). The surfactant can be used alone or in combination of two or more.

[0213] [Pattern Formation Method]

[0214] When the resist material of the present invention is used in the manufacture of various integrated circuits, known photolithography techniques can be used. For example, as for the pattern forming method, a method comprising the following steps can be cited:

[0215] (i) forming a resist film on a substrate using the resist material;

[0216] (ii) exposing the resist film to high energy radiation, and

[0217] (iii) The exposed resist film is developed using a developer.

[0218] [Step (i)]

[0219] The resist material of the present invention is applied to a substrate (Si, SiO2, SiN, SiON, TiN, WSi, BPSG, SOG, organic anti-reflection film, etc.) for integrated circuit manufacturing or a substrate (Cr, CrO, CrON, MoSi2, SiO2, etc.) for mask circuit manufacturing by a suitable coating method such as spin coating, roller coating, flow coating, dip coating, spray coating, scraping coating, etc. to make the coating film thickness 0.01 to 2 μm. It is pre-baked on a hot plate for 30 seconds to 20 minutes to form a resist film.

[0220] In step (i), the pre-baking temperature (firing temperature) is preferably 130° C. or higher. If the temperature is 130° C. or higher, a weak acid is generated from the thermal acid generator and used as a catalyst to efficiently advance the cross-linking reaction.

[0221] [Step (ii)]

[0222] Then, the resist film is exposed using high-energy radiation. Examples of the high-energy radiation include ultraviolet rays, far ultraviolet rays, EB, EUV with a wavelength of 3 to 15 nm, X-rays, soft X-rays, excimer lasers, gamma rays, synchrotron radiation, and the like. When ultraviolet rays, far ultraviolet rays, EUV, X-rays, soft X-rays, excimer lasers, gamma rays, synchrotron radiation, and the like are used as the high-energy radiation, the exposure amount is preferably about 1 to 200 mJ / cm directly or using a mask for forming a target pattern. 2 , more preferably about 10 to 100 mJ / cm 2 When high-energy radiation is used, the exposure amount is preferably about 0.1 to 100 μC / cm 2 , preferably about 0.5 to 50 μC / cm 2 The resist material of the present invention is particularly suitable for fine patterning by KrF excimer laser, ArF excimer laser, EB, EUV, X-ray, soft X-ray, gamma ray, synchrotron radiation among high-energy rays, and is particularly suitable for fine patterning by EB or EUV.

[0223] After exposure, a post-exposure bake (PEB) may be performed on a hot plate or in an oven, preferably at 50-150° C. for 10 seconds to 30 minutes, more preferably at 60-120° C. for 30 seconds to 20 minutes.

[0224] [Step (iii)]

[0225] After exposure or PEB, a developer containing 0.1 to 10% by mass, preferably 2 to 5% by mass, of an alkaline aqueous solution of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, or the like is used to develop the exposed resist film for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes, by conventional methods such as dipping, puddle, and spraying. The illuminated portion will dissolve in the developer, while the unexposed portion will not dissolve, and a target positive pattern will be formed on the substrate.

[0226] [Example]

[0227] Hereinafter, the present invention will be specifically described using Examples and Comparative Examples, but the present invention is not limited thereto.

[0228] [Examples 1-1 to 1-20, Comparative Examples 1-1 to 1-10] Preparation of Resist Compositions

[0229] In a solvent in which 50 ppm of OMNOVA surfactant PolyFox PF-636 was dissolved as a surfactant, solutions of the components shown in Tables 1 and 2 were prepared, and the solutions were filtered through a 0.2 μm filter to prepare resist compositions (for examples: R-1 to R-20, for comparative examples: cR-1 to cR-10). The contents of each resist composition are shown in Tables 1 and 2.

[0230] In Tables 1 and 2, the components are as follows.

[0231] Organic solvent: PGMEA (propylene glycol monomethyl ether acetate) DAA (diacetone alcohol)

[0232] EL(ethyl lactate)

[0233] (In the table, they are represented as P, D, and E respectively)

[0234] ·Base polymer: P-1~P-9, cP-1~cP-2

[0235] [Chemistry 40]

[0236]

[0237] [Chemistry 41]

[0238]

[0239] The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the above-mentioned base polymers: P-1 to P-9 and cP-1 to cP-2 are as follows, respectively.

[0240] P-1Mw:8100Mw / Mn:1.83

[0241] P-2Mw:7500Mw / Mn:1.89

[0242] P-3Mw:8600Mw / Mn:1.66

[0243] P-4Mw:10100Mw / Mn:1.58

[0244] P-5Mw:9800Mw / Mn:1.72

[0245] P-6Mw:11200Mw / Mn:1.50

[0246] P-7Mw:8700Mw / Mn:1.75

[0247] P-8Mw:9300Mw / Mn:1.63

[0248] P-9Mw:10400Mw / Mn:1.54

[0249] cP-1Mw:7900Mw / Mn:1.87

[0250] cP-2Mw:9900Mw / Mn:1.85

[0251] ·Acid generator: PAG-1~PAG-2

[0252] [Chemistry 42]

[0253]

[0254] Quencher: Q-1~Q-7, cQ-1~cQ-2

[0255] [Chemistry 43]

[0256]

[0257] · Cross-linking agent: X-1~X-4, cX-1

[0258] [Chemistry 44]

[0259]

[0260] Thermal acid generator: T-1~T-4

[0261] [Chemistry 45]

[0262]

[0263] [Table 1]

[0264]

[0265]

[0266] ※1 Example 1-1 to 1-3: P / D = 2570 / 1100 Example 1-4 to 1-20: P / D / E = 1380 / 340 / 1720 [Table 2]

[0267]

[0268]

[0269] ※2 Comparative Examples 1-1 to 1-3: P / D = 2570 / 1100

[0270] Comparative Examples 1-4 to 1-10: P / D / E = 1380 / 340 / 1720

[0271] [Examples 2-1 to 2-20, Comparative Examples 2-1 to 2-10] Heat Resistance Evaluation

[0272] The resist compositions R-1 to R-20 and cR-1 to cR-10 were spin-coated on an 8-inch wafer and baked for 60 seconds using a hot plate at the temperature described in Tables 3 and 4 to prepare a resist film. The resist film was then peeled off from the wafer using a scraper to obtain an evaluation sample. Differential scanning calorimetry (DSC) was performed on the above-mentioned heat resistance evaluation sample to determine the glass transition point. The glass transition point was determined using a differential scanning calorimeter (Thermo plus EVO2DSC8231) manufactured by Rigaku Co., Ltd.

[0273] The point where the base line shift was observed in the DSC curve was defined as the glass transition temperature, and the heat resistance of the resist was evaluated based on the following criteria. The results of Examples 2-1 to 2-20 are shown in Table 3, and the results of Comparative Examples 2-1 to 2-10 are shown in Table 4.

[0274] (Judgment Criteria)

[0275] ◎: Glass transition temperature is above 110℃

[0276] 0:Glass transition temperature is above 105℃

[0277] △: Glass transition temperature is less than 105°C [Table 3]

[0278]

[0279] [Table 4]

[0280]

[0281] [Examples 3-1 to 3-20, Comparative Examples 3-1 to 3-10] Evaluation of Dissolution Contrast

[0282] The resist compositions R-1 to R-20 and cR-1 to cR-10 were spin-coated on a Si substrate on which a 20 nm thick silicon-containing spin-coating hard mask SHB-A940 (containing 43% by mass of silicon) manufactured by Shin-Etsu Chemical Co., Ltd. was formed, and pre-baked at 130° C. for 60 seconds using a hot plate to prepare a resist film having a thickness of 50 nm. This was exposed using a KrF exposure machine (manufactured by Nikon Co., Ltd.; S206D), PEB was performed on a hot plate at 95° C. for 60 seconds, and developed with a 2.38% by mass TMAH aqueous solution for 30 seconds. The thickness of the resist film after the development treatment was measured, and the relationship between the exposure amount and the thickness of the resist film after the development treatment was plotted to analyze the dissolution contrast. Furthermore, the contrast was evaluated according to the following criteria, and these were used as Examples 3-1 to 3-20 and Comparative Examples 3-1 to 3-10. The film thickness was measured using a film thickness meter VM-2210 manufactured by Hitachi Advanced Industries, Ltd.

[0283] Regarding the representative compositions in the above-mentioned dissolution contrast evaluation, the contrast curves of the resist films of Examples 3-9 and Comparative Examples 3-10 are shown in FIG. Figure 1 .and, Figure 1 The vertical axis is the value obtained by normalizing the film thickness after the development treatment with the film thickness before the treatment. The contrast values ​​in Tables 5 and 6 represent the slope of the change in film thickness with respect to the exposure amount at the point where the developer solubility of the resist film changes rapidly. In the interval from when the film thickness is less than 80% of the initial film thickness until the film is completely dissolved, the slope when the horizontal axis is the logarithm of the exposure amount and the vertical axis is the standardized film thickness is defined as the contrast value. The contrast of the resist film formed by each resist composition is evaluated based on the absolute value of the contrast value as follows. The results of Examples 3-1 to 3-20 are shown in Table 5, and the results of Comparative Examples 3-1 to 3-10 are shown in Table 6.

[0284] (Judgment Criteria)

[0285] ◎: The absolute value of the contrast ratio is 4.5 or more

[0286] ○: The absolute value of the contrast ratio is 4 or more and less than 4.5

[0287] △: The absolute value of the contrast ratio is less than 4

[0288] [Table 5]

[0289]

[0290]

[0291] [Table 6]

[0292]

[0293] [Examples 4-1 to 4-20, Comparative Examples 4-1 to 4-5] EB Lithography Evaluation

[0294] The resist compositions R-1 to R-20 and cR-1 to cR-10 were spin-coated on an anti-reflection film DUV-42 manufactured by Nissan Chemical Co., Ltd. with a film thickness of 61 nm on an 8-inch wafer, and pre-baked at 130°C for 60 seconds using a hot plate to prepare a resist film with a film thickness of 50 nm. The resist film was exposed to an LS pattern with a size of 18 nm and a pitch of 36 nm on the wafer using an electron beam lithography device (ELS-F125, accelerating voltage 125 kV) manufactured by ELIONIX Corporation, and after exposure, PEB was performed at 90°C for 60 seconds. After PEB, immersion development was performed for 30 seconds with a 2.38 mass % TMAH aqueous solution, eluted with an aqueous solution of an eluting material containing a surfactant, and spin dried to obtain a positive pattern. The developed LS pattern was observed with a Hitachi Advanced Technology Co., Ltd. SEM (S9380) to obtain the optimal exposure dose Eop (mJ / cm2) for obtaining a LS pattern with a line width of 18 nm and a pitch of 36 nm. 2 ), and set it as sensitivity. In addition, the value (3σ) tripled by the standard deviation (σ) calculated from the measurement results of the pattern size was obtained as the pattern width deviation (LWR). The results of Examples 4-1 to 4-20 are shown in Table 7, and the results of Comparative Examples 4-1 to 4-10 are shown in Table 8.

[0295] (Judgment Criteria)

[0296] ◎: LWR value is less than 4.0

[0297] ○: LWR value is 4.0 or more and less than 4.5

[0298] △: LWR value is 4.5 or more

[0299] [Table 7]

[0300]

[0301]

[0302] [Table 8]

[0303]

[0304]

[0305] From Tables 3 to 8, and Figure 1The results shown show that the resist material of the present invention has excellent heat resistance, resolution, and LWR. On the other hand, in the resist compositions cR-1 to cR-4 (Comparative Examples 1-1 to 1-4), since the base polymer does not contain a repeating unit containing a predetermined reactive group, the heat resistance (glass transition temperature), resolution, and LWR are poor. In addition, in the resist compositions cR-5 to cR-10 (Comparative Examples 1-5 to 1-10), since they do not contain any one or more of the quencher, cross-linker, and thermal acid generator in the present invention, the heat resistance (glass transition temperature), resolution, and LWR are poor. From the above, it can be seen that the resist material of the present invention, by having all of the specific base polymer (P), the specific cross-linker, the thermal acid generator, the specific quencher, and the organic solvent, will become a resist material with small edge roughness, small dimensional deviation, excellent resolution, and good heat resistance.

[0306] This specification includes the following inventions.

[0307] [1]: A resist material comprising:

[0308] A base polymer (P) comprising a repeating unit (A) containing a reactive group represented by the following formula (a1) or (a2) and a repeating unit (B) having an acid-decomposable group,

[0309] A cross-linking agent having a structure represented by the following formula (1),

[0310] Thermal acid generators,

[0311] A photodegradable quencher represented by the following formula (2), and

[0312] Organic solvents,

[0313] [Chemistry 46]

[0314]

[0315] In the formula, R A are each independently a hydrogen atom or a methyl group, Y a1 , Y a2 Each independently represents a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 14 carbon atoms and having an ester bond, an ether bond, an amide bond or a lactone ring, a1 is a hydrogen atom, a fluorine atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, R a1 With Y a1 They may also be bonded to each other and to the carbon atoms on the aromatic rings to which they are bonded to form a ring, p is 1 or 2, q is an integer from 0 to 4, 1≤p+q≤5, r is 0 or 1,

[0316] [Chemistry 47]

[0317]

[0318] In the formula, R 1a is an organic group which may have a substituent, L 1 is a linking group selected from a single bond, an ester bond, and an ether bond, R 1b is a single bond or a divalent organic group, n is an integer from 2 to 4,

[0319] [Chemistry 48]

[0320]

[0321] R 21 ~R 23 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and R 21 , R 22 and R 23 Any two of them may be bonded to each other and form a ring together with the sulfur atom to which they are bonded, l is an integer from 0 to 4, R 2b is a halogen atom, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 18 carbon atoms which may have a substituent, an amino group which may have a substituent, or a phenyl group which may have a substituent, and when l is 2 or more, R 2b They can also be different from each other, L 2a is a single bond, an ester bond, or a divalent linking group having 1 to 8 carbon atoms, R 2a is a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms which may have a substituent, and R 2a With R 2b They may also be bonded to each other and to form a ring together with the carbon atoms to which they are bonded.

[0322] [2]: The resist material according to [1], wherein the base polymer (P) contains a repeating unit (C) having a structural site that is decomposed by irradiation with active light or radiation to generate an acid.

[0323] [3]: The resist material according to [2], wherein the repeating unit (C) contained in the base polymer (P) is represented by the following formula (c):

[0324] [Chemistry 49]

[0325]

[0326] In the formula, R c1 is a hydrogen atom or a methyl group, Z 1 is a single bond or an ester bond, Z 2 is a single bond or a divalent organic group having 1 to 20 carbon atoms, and may contain an ester bond, an ether bond, a lactone ring, an amide bond, a sultone ring, or an iodine atom. c1 ~Rfc4 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of them contains a fluorine atom, R c2 ~R c4 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and R c2 , R c3 and R c4 Any two of them may be bonded to each other and form a ring together with the sulfur atom to which they are bonded.

[0327] [4]: The resist material according to any one of [1] to [3], wherein the repeating unit (B) contained in the base polymer (P) is represented by the following formula (b):

[0328] [Chemistry 50]

[0329]

[0330] In the formula, R b is a hydrogen atom or a methyl group, L b is a single bond, a phenylene group, a naphthylene group, or a divalent linking group having 1 to 15 carbon atoms and having at least one of an ester bond, an ether bond, a lactone ring, an amide group, and a heteroatom, R AL It is an acid-labile group.

[0331] [5]: The resist material according to any one of [1] to [4], wherein the repeating unit (A) contained in the base polymer (P) is represented by the formula (a1) and contains 30 mol% or more of the total of the repeating units in the base polymer (P).

[0332] [6]: A pattern forming method comprising: a step of forming a resist film on a substrate using a resist material as described in any one of [1] to [5], a step of exposing the resist film to high-energy radiation, and a step of developing the exposed resist film using a developer.

[0333] [7]: The pattern forming method according to [6], wherein in the step of forming the resist film, the firing temperature is set to 130° C. or higher.

[0334] The present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are illustrative only, and those having substantially the same configuration as the technical concept described in the claims of the present invention and having the same functions and effects are all within the technical scope of the present invention.

Claims

1. A resist material, characterized by comprising: A base polymer (P) comprising a repeating unit (A) containing a reactive group represented by the following formula (a1) or (a2) and a repeating unit (B) having an acid-decomposable group, A cross-linking agent having a structure represented by the following formula (1), Thermal acid generators, A photodegradable quencher represented by the following formula (2), and Organic solvents, In the formula, R A are each independently a hydrogen atom or a methyl group, Y a1 , Y a2 Each independently represents a single bond, a phenylene group or a naphthylene group, or a linking group having 1 to 14 carbon atoms and having an ester bond, an ether bond, an amide bond or a lactone ring, a1 is a hydrogen atom, a fluorine atom or a saturated hydrocarbon group having 1 to 6 carbon atoms, R a1 With Y a1 They may also be bonded to each other and to the carbon atoms on the aromatic rings to which they are bonded to form a ring, p is 1 or 2, q is an integer from 0 to 4, 1≤p+q≤5, r is 0 or 1, In the formula, R 1a is an organic group which may have a substituent, L 1 is a linking group selected from a single bond, an ester bond, and an ether bond, R 1b is a single bond or a divalent organic group, n is an integer from 2 to 4, R 21 ~R 23 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and R 21 , R 22 and R 23 Any two of them may be bonded to each other and form a ring together with the sulfur atom to which they are bonded, l is an integer from 0 to 4, R 2b is a halogen atom, a hydroxyl group, a nitro group, a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 18 carbon atoms which may have a substituent, an amino group which may have a substituent, or a phenyl group which may have a substituent, and when l is 2 or more, R 2b They can also be different from each other, L 2a is a single bond, an ester bond, or a divalent linking group having 1 to 8 carbon atoms, R 2a is a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms which may have a substituent, and R 2a With R 2b They may also be bonded to each other and to form a ring together with the carbon atoms to which they are bonded.

2. The resist material according to claim 1, wherein The base polymer (P) contains a repeating unit (C) having a structural site that is decomposed by irradiation with active light or radiation to generate an acid.

3. The resist material according to claim 2, wherein The repeating unit (C) contained in the base polymer (P) is represented by the following formula (c): In the formula, R c1 is a hydrogen atom or a methyl group, Z 1 is a single bond or an ester bond, Z 2 is a single bond or a divalent organic group having 1 to 20 carbon atoms, and may contain an ester bond, an ether bond, a lactone ring, an amide bond, a sultone ring, or an iodine atom. c1 ~Rf c4 are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, but at least one of them contains a fluorine atom, R c2 ~R c4 are each independently a monovalent hydrocarbon group having 1 to 20 carbon atoms which may contain a hetero atom, and R c2 , R c3 and R c4 Any two of them may be bonded to each other and form a ring together with the sulfur atom to which they are bonded.

4. The resist material according to claim 1, wherein The repeating unit (B) contained in the base polymer (P) is represented by the following formula (b): In the formula, R b is a hydrogen atom or a methyl group, L b is a single bond, a phenylene group, a naphthylene group, or a divalent linking group having 1 to 15 carbon atoms and having at least one of an ester bond, an ether bond, a lactone ring, an amide group, and a heteroatom, R AL It is an acid-labile group.

5. The resist material according to claim 1, wherein The repeating unit (A) contained in the base polymer (P) is represented by the formula (a1), and is contained in an amount of 30 mol% or more based on the total of the repeating units in the base polymer (P).

6. A pattern forming method, characterized by comprising the following steps: forming a resist film on a substrate using the resist material according to any one of claims 1 to 5, The resist film is exposed to high energy radiation, and The exposed resist film is developed using a developer.

7. The pattern forming method according to claim 6, wherein: In the step of forming the resist film, the firing temperature is set to 130° C. or higher.

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