KR20190136988A - Resist composition and patterning process - Google Patents

Abstract

The present invention relates to a resist material comprising: a base polymer; and onium salt of N-carbonylsulfonamide having an iodinated benzene ring. The resist material provides high sensitivity and minimal line LWR, and improved CDU in both a positive resist material and a negative resist material.

Description

Resist material and pattern formation method {RESIST COMPOSITION AND PATTERNING PROCESS}

Cross Reference to Related Application

This non-application is 35 U.S.C. § 119 (a) claims the priority of patent applications 2018-104855 and 2019-028583, filed May 31, 2018 and February 20, 2019, respectively, in Japan, the entire contents of which are hereby incorporated by reference. Quote it as:

Technical Field

The present invention relates to a resist material and a pattern forming method.

With the expansion of the IoT market, higher integration, higher speed, and lower power consumption of LSIs are required, and the pattern rule is rapidly being refined. In particular, logic devices are driving miniaturization. As a state-of-the-art micronization technique, mass production of 10 nm node microelectronic devices has been accomplished by double patterning, triple patterning, and quadro patterning of immersion ArF lithography. Consideration is being given to the production of 7 nm node devices by next-generation EUV lithography of 13.5 nm.

In EUV lithography, a line width of 20 nm or less can be formed in the line pattern, and a chemically amplified resist material can be applied. However, since the effect of image blur due to acid diffusion becomes greater, EUV lithography requires acid diffusion control than ArF lithography.

The chemically amplified resist material containing an acid generator capable of generating an acid by irradiation of light or EB is a chemically amplified positive resist material causing a deprotection reaction with an acid and a chemical amplification negative causing a crosslinking reaction with an acid. Type resist material. Quenchers are often added to these resist materials for the purpose of controlling the diffusion of the acid into the unexposed portions to improve contrast. The addition of the quencher was very effective for this purpose. Therefore, many amine quenchers have been proposed as disclosed in Patent Literatures 1-3.

As the pattern becomes finer and approaches the diffraction limit of the light, the contrast of the light decreases. As a result of the lowering of the contrast of light, in the positive resist film, the resolution of the hole pattern and the trench pattern and the decrease of the focus margin occur. In order to prevent the influence of the resolution fall of a resist pattern by the contrast fall of light, the attempt to improve the dissolution contrast of a resist film is made.

A chemically amplified resist material using an acid propagation mechanism capable of generating acid by acid has been proposed. Usually, the concentration of acid increases linearly with the increase of the exposure dose. In the case of the acid propagation mechanism, the acid concentration rapidly increases nonlinearly with respect to the increase in the exposure amount. The acid propagation system has the advantage of further increasing the advantages such as high contrast and high sensitivity of the chemically amplified resist film, but the environmental resistance due to contamination of the amine deteriorates, so that the resolution of the chemically amplified resist film such as a decrease in the limit resolution by increasing the acid diffusion distance Deteriorate the defect further. If you want to put it to practical use, it is very difficult to control.

Another method for increasing contrast is a method of lowering the amine concentration in accordance with an increase in the exposure dose. The application of the compound which loses the function as a quencher by light irradiation to this can be considered.

The acid labile group used in methacrylate polymers for ArF lithography resist materials is dehydrated by using a photoacid generator (referred to as " α-fluorinated sulfonic acid ") capable of generating sulfonic acid in which the α position is substituted with fluorine. The protective reaction proceeds, but the deprotection reaction does not proceed with sulfonic acid (referred to as "α-non-fluorinated sulfonic acid") or an acid generator capable of generating a carboxylic acid in which the α position is not substituted with fluorine. If a sulfonium salt or iodonium salt capable of generating α-fluorinated sulfonic acid is mixed with a sulfonium salt or iodonium salt capable of generating α non-fluorinated sulfonic acid, a sulfonium salt or iodo that may generate α non-fluorinated sulfonic acid The nium salt causes ion exchange with α fluorinated sulfonic acid. Since alpha fluorinated sulfonic acid generated by light irradiation is returned to sulfonium salt or iodonium salt by ion exchange, alpha nonfluorinated sulfonic acid and sulfonium salt or iodonium salt of carboxylic acid function as a quencher.

Moreover, the sulfonium salt and iodonium salt which can generate (alpha) non-fluorinated sulfonic acid also function as a photodegradable quencher, since the ability as a quencher loses by photolysis. Non-Patent Document 1 discloses that the margin of the trench pattern is expanded by adding a photodegradable quencher, although the structural formula is not known. However, the impact on performance improvement is marginal. The development of the quencher which improves contrast more is calculated | required.

In patent document 4, the carboxylic acid which has an amino group by light irradiation generate | occur | produces, and the onium salt type quencher in which basicity falls when this lactam is produced | generated by acid is proposed. Acid diffusion is controlled by the high basicity of the unexposed portion having a low amount of acid generated by the mechanism of lowering the basicity due to the acid, and the acid diffusion due to the lowered basicity of the quencher in the overexposed portion having a large amount of acid generated. This is getting bigger. Thereby, the difference of the acid amount of an exposure part and an unexposed part can be widened, and contrast improvement is expected. In this case, however, the contrast is improved, but the acid diffusion control effect is lowered.

With the refinement of the pattern, the edge roughness LWR of the line pattern or the critical dimensional uniformity CDU of the hole pattern is a problem. The effect of localization or aggregation of base polymers and acid generators on LWRs, and the effect of diffusion of acid generated is pointed out. As the resist film is thinned, the LWR tends to increase. Degradation of LWR due to thinning with progress of miniaturization is a serious problem.

In EUV lithography resist materials, it is necessary to simultaneously achieve high sensitivity, high resolution, low LWR, and CDU improvement. If the acid diffusion distance is shortened, the LWR is small but reduced. For example, by lowering the PEB temperature, the LWR becomes small, but the degree of reduction is reduced. Increasing the amount of the quencher decreases the LWR, but decreases it. There is a need to overcome the tradeoff between sensitivity, LWR and CDU. Like EUV, EB is a high energy ray, and there is a trade-off between sensitivity and LWR or CDU.

The energy of EUV is much higher compared to ArF excimer lasers. The number of photons of EUV exposure is one-fourteenth of that of ArF exposure. Moreover, the dimensions of the pattern formed by EUV lithography are less than one half of ArF lithography. For this reason, EUV lithography is susceptible to photon fluctuations. The variation of the photon number in the extreme wavelength radiation region is shot noise of the physical phenomenon, and this influence cannot be eliminated.

Stochastics are drawing attention. Although the effect of shot noise cannot be eliminated, it is discussed how to reduce this effect. The effect of shot noise not only increases CDU and LWR, but also a phenomenon in which holes are occluded with a probability of one millionth. Occlusion of the holes leads to electrical conduction failures and the transistors do not operate, adversely affecting the performance of the device as a whole. As a method of reducing the effect of shot noise on the resist side, a method of increasing the absorption of the resist to absorb more photons, and the development of a single component low molecular weight resist has been proposed because the polymer type resist material causes variation.

As acid generators for increasing the absorption of resists, Patent Literatures 5 and 6 propose resist materials to which an acid generator of an onium salt having iodine on the anion side is added. This can improve both the sensitivity of the resist material and the LWR or CDU.

Patent Document 1: JP-A 2001-194776 Patent Document 2: JP-A 2002-226470 Patent Document 3: JP-A 2002-363148 Patent Document 4: JP-A 2015-090382 Patent Document 5: JP-A 2018-005224 Patent Document 6: JP-A 2015-025789

[Non-Patent Document 1] SPIE Vol. 7639 p76390W (2010) [Non-Patent Document 2] SPIE Vol. 9776 p97760V-1 (2016)

In chemically amplified resists using an acid as a catalyst, development of a quencher or an acid generator capable of reducing LWR and CDU with high sensitivity and development of a resist material that can contribute to reducing shot noise is required.

An object of the present invention is to provide a resist material having a high sensitivity and a low LWR or an improved CDU even in a positive resist material and a negative resist material, and a pattern forming method using the same.

The inventors of the present invention use the onium salt of N-carbonylsulfonamide having an iodinated benzene ring as a quencher or an acid generator, thereby providing high sensitivity, low LWR or improved CDU, high contrast, and high resolution. It was found that a wider margin of resist material could be obtained.

In one aspect, the present invention provides a resist material comprising a base polymer and an onium salt having the following formula (A).

Wherein R ¹ represents hydrogen, hydroxy, a C ₁ -C ₆ alkyl group, a C ₁ -C ₆ alkoxy group, a C ₂ -C ₇ acyloxy group, a C ₂ -C ₇ alkoxycarbonyl group, a C ₁ -C ₄ alkylsulfo Nyloxy group, fluorine, chlorine, bromine, amino, nitro, cyano, -NR ^1A -C (= O) -R ^1B or -NR ^1A -C (= O) -OR ^1B , the alkyl group, alkoxy group, acyl Some or all of the hydrogen atoms of the oxy group, the alkoxycarbonyl group and the alkylsulfonyloxy group may be substituted with halogen, R ^1A is hydrogen or a C ₁ -C ₆ alkyl group, and R ^1B is a C ₁ -C ₆ alkyl group or C ₂ -C ₈ alkenyl group; R ² is a C ₁ -C ₁₀ alkyl group or a C ₆ -C ₁₀ aryl group, and part or all of its hydrogen is amino, nitro, cyano, C ₁ -C ₁₂ alkyl, C ₁ -C ₁₂ alkoxy, C _2- May be substituted with C ₁₂ alkoxycarbonyl, C ₂ -C ₁₂ acyl, C ₂ -C ₁₂ alkylcarbonyloxy, hydroxy or halogen; X ¹ is a single bond or a C ₁ -C ₂₀ divalent linking group, and may include an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen, a hydroxy group or a carboxy group; m and n are integers satisfying 1 ≦ m ≦ 5, 0 ≦ n ≦ 4 and 1 ≦ m + n ≦ 5.

M ⁺ is a sulfonium cation having the formula (Aa), an iodonium cation having the formula (Ab) or an ammonium cation having the formula (Ac).

Wherein, R ^a1 ~R ^a3 independently is halogen, or contains a heteroatom and may good C ₁ -C _{20 1,} or a hydrocarbon group, or R ^a1, in which the dog 2 of R ^a2 and R ^a3 each other to which they are attached, respectively A ring may be formed together with a bonding sulfur atom; R ^a4 and R ^a5 are each independently a C ₁ -C ₂₀ monovalent hydrocarbon group which may contain a halogen or a hetero atom; R ^a6 to R ^a9 are each independently hydrogen or a C ₁ -C ₂₄ monovalent hydrocarbon group, and are halogen, hydroxy, carboxy, ether bond, ester bond, thiol, thioester bond, thionoester bond, dithioester bond , An amino group, a nitro group, a sulfone group or a ferrocenyl group may be included, R ^a6 and R ^a7 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, a pair of R ^a6 and R ^a7 and R ^a8 A pair of and R ^a9 may be bonded to each other to form a spiro ring together with the nitrogen atom to which they are bonded, R ^a8 and R ^a9 may be combined to form = C (R ^a10 ) (R ^a11 ), and R ^a10 and R ^a11 is each independently hydrogen or a C ₁ -C ₁₆ monovalent hydrocarbon group, and R ^a10 and R ^a11 may be bonded to each other to form a ring together with the carbon and nitrogen atoms to which they are bonded, and a double bond, oxygen in the ring Atomic sulfur Here, or it may contain a nitrogen atom.

Preferably m is an integer satisfying 2 ≦ m ≦ 4.

The resist material may further comprise an acid generator capable of generating sulfonic acid, imide acid or metic acid, and / or an organic solvent.

In one preferred embodiment, the base polymer comprises a repeating unit having the formula (a1) or a repeating unit having the formula (a2).

??? in which, R ^A is independently hydrogen or methyl, Y ¹ is a single bond, phenylene group, naphthylene group, or a C ₁ -C ₁₂ linking group containing an ester bond or a lactone ring, Y ² is a single bond or It is an ester bond and R <^11> and R <^12> is an acid labile group, respectively.

In one embodiment, the resist material is a chemically amplified positive resist material.

The base polymer may not include an acid labile group.

In one preferred embodiment, the resist material may further comprise a crosslinking agent. Typically, the resist material is a chemically amplified negative resist material.

In one preferred embodiment, the base polymer further comprises at least one repeating unit selected from repeating units having the following formulas (f1) to (f3).

Wherein each R ^A is independently hydrogen or methyl; Z ¹ is a single bond, a phenylene group, -OZ ^11- , -C (= O) -OZ ¹¹ -or -C (= O) -NH-Z ^11- , and Z ¹¹ is a C ₁ -C ₆ alkanediyl group , A C ₂ -C ₆ alkenediyl group or a phenylene group, and may include a carbonyl, ester bond, ether bond or hydroxy group; Z ² is a single bond, -Z ²¹ -C (= O) -O-, -Z ²¹ -O- or -Z ²¹ -OC (= O)-, Z ²¹ is a C ₁ -C ₁₂ alkanediyl group , Carbonyl group, ester bond or ether bond may be included; Z ³ is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, -C (= O) -OZ ³¹ -or -C (= O) -NH-Z ^31- , and Z ³¹ is C ₁ -C ₆ An alkanediyl group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with a trifluoromethyl group, or a C ₂ -C ₆ alkenediyl group, and may include a carbonyl group, an ester bond, an ether bond or a hydroxyl group; A is hydrogen or trifluoromethyl; R ²¹ to R ²⁸ are each independently a C ₁ -C ₂₀ monovalent hydrocarbon group which may contain a hetero atom, any two of R ²³ , R ²⁴ and R ²⁵ or any of R ²⁶ , R ²⁷ and R ²⁸ Two may be bonded to each other to form a ring together with a sulfur atom to which they are bonded; M ⁻ is a nonnucleophilic counter ion.

The resist material may further comprise a surfactant.

In another aspect, the present invention provides a method for forming a resist film by applying a resist material defined herein to a substrate, subjecting the resist film to heat treatment, exposing the resist film to high energy rays, and developing the exposed resist film to a developer. It provides a pattern forming method comprising the step of.

Most often, the high energy ray is an ArF excimer laser with a wavelength of 193 nm, or a KrF excimer laser with a wavelength of 248 nm, EB, or EUV with a wavelength of 3 to 15 nm.

In a further aspect, the present invention provides a sulfonium salt having the following formula (B):

Wherein R ¹ , R ² , X ¹ , m, n and R ^a1 to R ^a3 are as defined above.

The resist film containing the onium salt of N-carbonylsulfonamide having an iodinated benzene ring has a large absorption of EB and EUV of the sulfonamide having an iodinated benzene ring, thereby generating a large number of secondary electrons in the film, thereby improving sensitivity. It is possible to improve. The anion of the onium salt has a long bonding distance with the onium cation due to steric hindrances in which substituents are attached to both sides of the amide bond. . That is, the capacity as a quencher is high, whereby a high contrast can be obtained. Moreover, when it has a fluorinated alkyl group and an aryl group in front of a sulfonamide group, since the intensity | generation of the generated acid is high, it functions as an acid generator. In this case, acid diffusion functions as a controlled acid generator.

1 is a diagram showing a ¹ H-NMR spectrum of sulfonium salt 1 obtained in Synthesis Example 1-1.
FIG. 2 is a diagram showing ¹⁹ F-NMR spectra of sulfonium salt 1 obtained in Synthesis Example 1-1. FIG.

As used herein, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. The notation (C _n -C _m ) means a group containing n to m carbon atoms per group. As used herein, the term "iodinated" compound means an iodine containing compound. In the formula, Me means methyl and Ac means acetyl.

Abbreviations and acronyms have the following meanings.

EB: electron beam

EUV: extreme ultraviolet

Mw: weight average molecular weight

Mn: number average molecular weight

Mw / Mn: molecular weight distribution or dispersion

GPC: Gel Permeation Chromatography

PEB: Post Exposure Baking

PAG: Photoacid Generator

LWR: Linewidth Roughness

CDU: Critical Dimension Uniformity

Resist  material

The resist material of the present invention is defined to include an onium salt of N-carbonylsulfonamide (hereinafter referred to as iodide benzene ring-containing sulfonamide) having a base polymer and an iodide benzene ring. When the onium salt is a sulfonium salt or an iodonium salt, these are acid generators that generate a benzene ring-containing sulfonamide iodide by light irradiation, but also function as a quencher because it has a form of a strongly basic sulfonium salt or iodonium salt. . The said iodide benzene ring containing sulfonamide functions as an acid generator, since strong acid generate | occur | produces when it couple | bonds with the alkyl group and aryl group substituted with fluorine. On the other hand, when there is no fluorine atom, there is no acidity enough to cause the deprotection reaction of the acid labile group. Thus, in order to cause the deprotection reaction of the acid labile group separately, a strong acid sulfonic acid, imide acid, or It is effective to add an acid generator that generates meted acid. Here, the acid generator that generates sulfonic acid, imide acid, or methic acid may be an added type added to the base polymer, or may be a bound type bound to the base polymer.

When irradiating the resist material which contains the sulfonium salt or iodonium salt of the said iodide benzene ring containing sulfonamide, and the acid generator which generate | occur | produces a super acid or perfluoroalkylsulfonic acid, iodide benzene ring containing sulfonamide and purple Luoroalkylsulfonic acid is generated. Since all the acid generators are not decomposed, there are acid generators that are not decomposed in the vicinity. Here, when the sulfonium salt or iodonium salt of iodide benzene ring containing sulfonamide and perfluoroalkyl sulfonic acid coexist, the first perfluoroalkyl sulfonic acid undergoes ion exchange with the sulfonium salt or iodonium salt of iodide benzene ring containing sulfonamide. The sulfonium salt or iodonium salt of perfluoroalkylsulfonic acid is produced | generated, and the iodide benzene ring containing sulfonamide is released | released. This is because perfluoroalkyl sulfonate having higher strength as an acid is more stable. On the other hand, even if the sulfonium salt or iodonium salt of perfluoroalkyl sulfonic acid and iodide benzene ring containing sulfonamide coexist, ion exchange does not occur. Not only perfluoroalkylsulfonic acid, but also arylsulfonic acid, alkylsulfonic acid, imide acid, metedic acid and the like having higher acid strength than iodide benzene ring-containing sulfonamide, ion exchange in the same manner occurs.

Sulfonium salts, iodonium salts or ammonium salts of iodide benzene ring-containing sulfonamides not only inhibit acid diffusion but also have high absorption of EUV, resulting in secondary electrons, resulting in high sensitivity of the resist and reduced shot noise. Can be. The sulfonium salt, iodonium salt or ammonium salt of iodide benzene ring containing sulfonamide has not only an acid generator or quencher for acid diffusion control, but also a function as a sensitizer.

The resist material of the present invention is essential to include a sulfonium salt, iodonium salt or ammonium salt of iodide benzene ring-containing sulfonamide, but other sulfonium salts or iodonium salts may be separately added as a quencher. At this time, as sulfonium salt and iodonium salt added as a quencher, sulfonium salts and iodonium salts such as carboxylic acid, sulfonic acid, imide acid and saccharin are suitable. In this case, the carboxylic acid may not necessarily be fluorinated.

The resist material of the present invention is an acid generator comprising a sulfonium salt or iodonium salt of fluorosulfonamide bonded to an alkyl group or an aryl group substituted with fluorine, and a fluorosulfonamide bonded to an alkyl or aryl group having no fluorine atom. You may use combining the quencher which consists of sulfonium salts.

In order to improve the LWR, it is effective to suppress aggregation of the polymer and / or acid generator as described above. In order to suppress aggregation of the polymer, it is an effective means to reduce the difference between hydrophobicity and hydrophilicity or to lower the glass transition point (Tg) thereof. Specifically, it is effective to reduce the polarity difference between the hydrophobic acid labile group and the hydrophilic adhesive group, or to lower the Tg by using a compact adhesive group such as monocyclic lactone. In order to suppress aggregation of the acid generator, introducing a substituent to the cationic portion of triphenylsulfonium is an effective means. In particular, with respect to the methacrylate polymer for ArF lithography formed with the adhesive group of alicyclic protecting group and lactone, triphenylsulfonium formed only with an aromatic group is heterogeneous structure, and is low in compatibility. As a substituent introduce | transducing into triphenylsulfonium, the alicyclic group and lactone similar to what is used for a base polymer can be considered. Since the sulfonium salt is hydrophilic, when lactone is introduced, the hydrophilicity is too high, the compatibility with the polymer is lowered, and the sulfonium salt aggregates. The introduction of a hydrophobic alkyl group can uniformly disperse the sulfonium salt in the resist film. WO 2011/048919 proposes a method of improving LWR by introducing an alkyl group into a sulfonium salt capable of generating α-fluorinated sulfonimide acid.

Further attention regarding the LWR improvement is the dispersion of the quencher. Even if the dispersibility of the acid generator in the resist film is improved, if the quencher is non-uniformly present, it may cause a decrease in LWR. Also in a sulfonium salt type quencher, introducing a substituent such as an alkyl group into the cation portion of triphenylsulfonium is effective for improving the LWR. Moreover, introducing a halogen atom into a sulfonium salt type quencher improves hydrophobicity efficiently and improves dispersibility. Introduction of bulky halogen atoms such as iodine is effective not only in the cation portion of the sulfonium salt but also in the anion portion. The sulfonium salt of the iodide benzene ring containing sulfonamide which concerns on this invention improves the dispersibility of the quencher in a resist film, and reduces LWR by introducing an iodine atom into an anion part.

The LWR reduction effect of the sulfonium salt, iodonium salt, or ammonium salt of the iodide benzene ring-containing sulfonamide is effective in any of the negative pattern formation by the organic solvent phenomenon also in the positive pattern formation or the negative pattern formation by alkali development. Do.

Iodide Benzene ring  Of sulfonamides Onium salt

The resist material of this invention contains the onium salt of the iodide benzene ring containing sulfonamide which has a following formula (A).

Formula (A) of, R ¹ is a hydrogen atom, a hydroxy group, C ₁ -C ₆ alkyl, C ₁ -C ₆ alkoxy group, C ₂ -C ₇ acyloxy group, C ₂ -C ₇ alkoxycarbonyl group, C ₁ -C ₄ alkylsulfonyloxy group, fluorine atom, chlorine atom, bromine atom, amino group, nitro group, cyano group, -NR ^1A -C (= 0) -R ^1B or -NR ^1A -C (= 0) -OR ^1B . Some or all of the hydrogen atoms of the alkyl group, alkoxy group, acyloxy group, alkoxycarbonyl group and alkylsulfonyloxy group may be substituted with a halogen atom. R ^1A is a hydrogen atom or a C ₁ -C ₆ alkyl group. R ^1B is a C ₁ -C ₆ alkyl group or a C ₂ -C ₈ alkenyl group.

The C ₁ -C ₆ alkyl group may be linear, branched or cyclic, and examples thereof include methyl group, ethyl group, n-propyl group, isopropyl group, cyclopropyl group, n-butyl group, isobutyl group and sec-butyl group. and tert-butyl group, cyclobutyl group, n-pentyl group, cyclopentyl group, n-hexyl group, cyclohexyl group and the like. Examples of C ₁ -C ₆ alkoxy group, C ₂ -C ₇ acyloxy group, C ₂ -C ₇ alkyl portion of the alkoxy group, may be mentioned as examples of the above-described alkyl group. Examples of the C ₁ -C ₄ alkyl part of the alkylsulfonyl group, there may be mentioned that the carbon number of 1 to 4. Examples of the above-described alkyl group. The C ₂ -C ₈ alkenyl group may be linear, branched or cyclic, and examples thereof include a vinyl group, 1-propenyl group and 2-propenyl group. As said aralkyl group, a benzyl group, a phenethyl group, etc. are mentioned. Among these, as R ¹ , a fluorine atom, a chlorine atom, a bromine atom, a hydroxyl group, an amino group, a C ₁ -C ₃ alkyl group, a C ₁ -C ₃ alkoxy group, a C ₂ -C ₄ acyloxy group, -NR ^1A -C (= O) -R ^1B or -NR ^1A -C (= 0) -OR ^1B and the like are preferable.

Formula (A) of, R ² is C ₁ -C ₁₀ alkyl or C ₆ -C ₁₀ aryl group, a part or all of the hydrogen atoms an amino group, a nitro group, a cyano group, C ₁ -C ₁₂ alkyl, C ₁ It may be substituted with a -C ₁₂ alkoxy group, a C ₂ -C ₁₂ alkoxycarbonyl group, a C ₂ -C ₁₂ acyl group, a C ₂ -C ₁₂ alkylcarbonyloxy group, a hydroxy group or a halogen atom.

The C ₁ -C ₁₀ alkyl group may be linear, branched or cyclic. Examples thereof include n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, in addition to the C ₁ -C ₆ alkyl group described above. Adamantyl group etc. are mentioned. C ₆ -C ₁₀ aryl group includes a phenyl group, a naphthyl group or the like.

In formula (A), X ¹ is a single bond or a C ₁ -C ₂₀ divalent linking group, and includes an ether bond, carbonyl group, ester bond, amide bond, sultone ring, lactam ring, carbonate bond, halogen atom, hydroxy group or carboxyl group You may do it. Among these, as X ¹ , a single bond is preferable.

In formula (A), m and n are integers which satisfy | fill 1 <= m <= 5, 0 <= n <= 4 and 1 <= m + n <= 5, Preferably m is an integer which satisfy | fills 2-4, n Is 0 or 1.

Although what is shown below is mentioned as an anion of an onium salt which has a formula (A), It is not limited to these.

In formula (A), M <^+> is a sulfonium cation which has a following formula (Aa), an iodonium cation which has a following formula (Ab), or an ammonium cation which has a following formula (Ac).

When M ⁺ is a sulfonium cation having the formula (Aa), for example, the onium salt having the formula (A) is a sulfonium salt having the following formula (B).

Wherein R ¹ , R ² , X ¹ , m, n and R ^a1 to R ^a3 are as defined above.

In formulas (Aa) and (Ab), R ^a1 to R ^a3 are each independently a C ₁ -C ₂₀ monovalent hydrocarbon group which may contain a halogen atom or a hetero atom. Any two of R ^a1 , R ^a2 and R ^a3 may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. R ^a4 and R ^a5 are each independently a C ₁ -C ₂₀ monovalent hydrocarbon group which may contain a halogen atom or a hetero atom.

The monovalent hydrocarbon group may be linear, branched or cyclic, and examples thereof include C ₁ -C ₂₀ alkyl group, C ₂ -C ₁₂ alkenyl group, C ₂ -C ₁₂ alkynyl group, C ₆ -C ₂₀ aryl group, C ₇ and the like can be -C ₁₂ aralkyl, C ₇ -C ₁₂ aryloxycarbonyl group. In addition, some or all of the hydrogen atoms of these groups may be substituted with a hydroxyl group, a carboxy group, a halogen atom, an oxo group, a cyano group, an amide bond, a nitro group, a sultone group, a sulfone group or a sulfonium salt-containing group, or Some of the carbon atoms may be substituted with ether bonds, ester bonds, carbonyl groups, carbonate bonds or sulfonic acid ester bonds.

In formula (Ac), R ^a6 to R ^a9 are each independently a hydrogen atom or a C ₁ -C ₂₄ monovalent hydrocarbon group, a halogen atom, a hydroxy group, a carboxyl group, an ether bond, an ester bond, a thiol group, a thioester bond, a tee An onoester bond, a dithioester bond, an amino group, a nitro group, a sulfone group, or a ferrocenyl group may be included. R ^a6 and R ^a7 may be mutually bonded to form a ring together with the nitrogen atom to which they are bonded, and a pair of R ^a6 and R ^{a7 and} a pair of R ^a8 and R ^a9 are mutually bonded to form a spiro ring together with the nitrogen atom to which they are bonded. May be formed, R ^a8 and R ^a9 may be combined to form = C (R ^a10 ) (R ^a11 ), and R ^a10 and R ^a11 are each independently a hydrogen atom or a C ₁ -C ₁₆ monovalent hydrocarbon group R ^a10 and R ^a11 may be bonded to each other to form a ring together with the carbon and nitrogen atoms to which they are bonded, and the ring may include a double bond, an oxygen atom, a sulfur atom, or a nitrogen atom.

The C ₁ -C ₂₄ monovalent hydrocarbon group may be linear, branched or cyclic, and examples thereof include C ₁ -C ₂₄ alkyl group, C ₂ -C ₂₄ alkenyl group, C ₂ -C ₂₄ alkynyl group, C ₆ -C ₂₀ Aryl groups, C ₇ -C ₂₀ aralkyl groups, combinations thereof, and the like.

Although what is shown below is mentioned as a sulfonium cation which has a formula (Aa), It is not limited to these.

Although the thing shown below is mentioned as an iodonium cation which has a formula (Ab), It is not limited to these.

Although what is shown below is mentioned as an ammonium cation which has a formula (Ac), It is not limited to these.

As a synthesis | combining method of the onium salt which has a formula (A), the method of performing ion exchange with the onium salt of weak acid rather than the iodide benzene ring containing sulfonamide is mentioned. Examples of the acid weaker than the iodide benzene ring-containing sulfonamide include hydrochloric acid, carbonic acid, carboxylic acid, and sulfonic acid containing no fluorine atom. Alternatively, the onium salt may be synthesized by ion exchange of the sodium salt of the iodide benzene ring-containing sulfonamide with onium chloride.

In the resist material of the present invention, the amount of the onium salt having the formula (A) is preferably 0.001 to 50 parts by weight, more preferably 0.01 to 20 parts by weight with respect to 100 parts by weight of the base polymer in terms of sensitivity and acid diffusion suppressing effect. desirable.

Base Polymer

In the case of a positive resist material, the base polymer contained in the resist material of the present invention includes a repeating unit containing an acid labile group, and as the repeating unit including an acid labile group, a repeating unit having the following formula (a1) or ( Preference is given to repeating units having a2). These units are referred to simply as repeating units (a1) and (a2).

In the formula, R ^A are each independently a hydrogen atom or a methyl group. Y ¹ is a C ₁ -C ₁₂ linking group including a single bond, a phenylene group or a naphthylene group, or an ester bond or a lactone ring. Y ² is a single bond or an ester bond. R ¹¹ and R ¹² are each an acid labile group. When the base polymer contains both repeating units (a1) and (a2), R ¹¹ and R ¹² may be the same or different.

Although what is shown below is mentioned as a monomer which gives a repeating unit (a1), It is not limited to these. R ^A and R ¹¹ are as defined above.

Although what is shown below is mentioned as a monomer which gives a repeating unit (a2), It is not limited to these. R ^A and R ¹² are as defined above.

The acid labile groups represented by R ¹¹ and R ¹² in the repeating units (a1) and (a2) include various groups such as those described in JP-A 2013-080033 (USP 8,574,817) and JP-A 2013-083821 (USP 8,846,303). Is chosen from.

Typically, as said acid labile group, group which has following formula (AL-1)-(AL-3) is mentioned.

In formulas (AL-1) and (AL-2), R ^L1 and R ^L2 are each independently a C ₁ -C ₄₀ monovalent hydrocarbon group, and each hetero atom such as an oxygen atom, a sulfur atom, a nitrogen atom, or a fluorine atom You may include it. The monovalent hydrocarbon group of good, even straight-chain, branched or cyclic As, C ₁ -C ₄₀ alkyl group and more preferably a C ₁ -C ₂₀ alkyl group. In formula (AL-1), a is an integer of 0-10, and the integer of 1-5 is preferable.

In formula (AL-2), R ^L3 and R ^L4 are each independently a hydrogen atom or a C ₁ -C ₂₀ monovalent hydrocarbon group, and may contain heteroatoms such as an oxygen atom, a sulfur atom, a nitrogen atom, and a fluorine atom. good. The monovalent hydrocarbon group may be linear, branched or cyclic, and a C ₁ -C ₂₀ alkyl group is preferable. Any two of R ^L2 , R ^L3 and R ^L4 may be bonded to each other to form a ring of 3 to 20 carbon atoms, preferably 4 to 16 carbon atoms, typically an alicyclic ring together with the carbon atom or carbon atom and oxygen atom to which they are bonded do.

In formula (AL-3), R ^L5 , R ^L6, and R ^L7 are each independently a C ₁ -C ₂₀ monovalent hydrocarbon group, and may contain heteroatoms such as oxygen, sulfur, nitrogen, and fluorine atoms. good. The monovalent hydrocarbon group may be linear, branched or cyclic, and a C ₁ -C ₂₀ alkyl group is preferable. Any two of R ^L5 , R ^L6 and R ^L7 may be bonded to each other to form a ring of 3 to 20 carbon atoms, preferably a ring of 4 to 16 carbon atoms, typically an alicyclic ring together with the carbon atoms to which they are bonded.

The base polymer may further include a repeating unit (b) containing a phenolic hydroxy group as an adhesive group. Although what is shown below is mentioned as a monomer which gives a repeating unit (b), It is not limited to these. Wherein R ^A is as defined above.

The base polymer may further include a repeating unit (c) selected from a hydroxy group, a carbonyl group, a lactone ring, an ether bond, an ester bond, a carbonyl group and a cyano group (other than the phenolic hydroxy group) as another adhesive group. Although what is shown below is mentioned as a suitable monomer which gives a repeating unit (c), It is not limited to these. Wherein R ^A is as defined above.

In another preferred embodiment, the base polymer further comprises a repeating unit (d) selected from units of indene, benzofuran, benzothiophene, acenaphthylene, chromone, coumarin, norbornadiene or derivatives thereof. You may also do it. Suitable monomers are illustrated below.

In addition to the repeating units described above, the base polymer may further comprise repeating units (e), examples of which include styrene, vinylnaphthalene, vinylanthracene, vinylpyrene, methyleneindane, vinylpyridine and vinylcarbazole.

In a further embodiment, the base polymer may further comprise a repeating unit (f) derived from an onium salt containing a polymerizable unsaturated bond. In JP-A 2005-084365, sulfonium salts and iodonium salts containing a polymerizable unsaturated bond in which a specific sulfonic acid is generated are proposed. In JP-A 2006-178317, a sulfonium salt in which sulfonic acid is directly connected to the main chain is proposed.

In a preferred embodiment, the base polymer may further include at least one repeating unit selected from the following formulas (f1), (f2) and (f3). These units are simply referred to as repeating units (f1), (f2) and (f3), and these may be used alone or in combination of two or more thereof.

In formulas (f1) to (f3), R ^A is as defined above. Z ¹ is a single bond, a phenylene group, -OZ ^11- , -C (= O) -OZ ¹¹ -or -C (= O) -NH-Z ^11- , and Z ¹¹ is a C ₁ -C ₆ alkanediyl group And a C ₂ -C ₆ alkenediyl group or a phenylene group, and may contain a carbonyl group, an ester bond, an ether bond or a hydroxy group. Z ² is a single bond, -Z ²¹ -C (= O) -O-, -Z ²¹ -O- or -Z ²¹ -OC (= O)-, Z ²¹ is a C ₁ -C ₁₂ alkanediyl group , A carbonyl group, an ester bond or an ether bond may be included. Z ³ is a single bond, methylene group, ethylene group, phenylene group, fluorinated phenylene group, -C (= O) -OZ ³¹ -or -C (= O) -NH-Z ^31- , and Z ³¹ is C _1- C ₆ alkanediyl group, a phenylene group, a fluorinated phenyl and the phenyl group canned group, or C ₂ -C ₆ al substituted with a methyl group as a group, a trifluoromethyl group, a carbonyl group, may contain an ester bond, an ether bond or a hydroxyl group. A is a hydrogen atom or a trifluoromethyl group.

In formulas (f1) to (f3), R ²¹ to R ²⁸ each independently represent a C ₁ -C ₂₀ monovalent hydrocarbon group which may contain a hetero atom. Any two of R ²³ , R ^24, and R ²⁵ , or any two of R ²⁶ , R ^27, and R ²⁸ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded.

The monovalent hydrocarbon group may be linear, branched or cyclic, and examples thereof include those mentioned above in the description of R ^a1 to R ^a3 in Formula (Aa). Examples of the sulfonium cations in the formulas (f2) and (f3) include those mentioned above as the sulfonium cations having the formula (Aa).

In formula (f1), M <^-> is a non-nucleophilic counter ion. Examples of this non-nucleophilic counter ion include halide ions such as chloride ions and bromide ions, triflate ions, 1,1,1-trifluoroethanesulfonate ions and fluoroalkylsulfonate ions such as nonafluorobutanesulfonate ions. Arylsulfonate ions such as ions, tosylate ions, benzenesulfonate ions, 4-fluorobenzenesulfonate ions, 1,2,3,4,5-pentafluorobenzenesulfonate ions; Alkylsulfonate ions, such as mesylate ion and butanesulfonate ion, bis (trifluoromethylsulfonyl) imide ion, bis (perfluoroethylsulfonyl) imide ion, bis (perfluorobutylsulfonyl) Imide ions such as imide ions; Met ion, such as a tris (trifluoromethylsulfonyl) methion ion and a tris (perfluoroethylsulfonyl) methion ion, is mentioned.

As said non-nucleophilic counter ion, the sulfonic acid ion which the alpha position which has a following formula (K-1) substituted by a fluorine atom, the sulfonic acid ion which the alpha and β position which has the following formula (K-2) substituted by a fluorine atom etc. are mentioned Can be.

In formula (K-1), R ⁵¹ is a hydrogen atom or a C ₁ -C ₂₀ alkyl group, a C ₂ -C ₂₀ alkenyl group, or a C ₆ -C ₂₀ aryl group, and an ether bond, ester bond, carbonyl group, or lactone ring Alternatively, a fluorine atom may be included. The alkyl group and alkenyl group may be linear, branched or cyclic.

In formula (K-2), R ⁵² is a hydrogen atom or a C ₁ -C ₃₀ alkyl group, a C ₂ -C ₃₀ acyl group, a C ₂ -C ₂₀ alkenyl group, a C ₆ -C ₂₀ aryl group, or C _6- C ₂₀ is an aryloxy group, an ether bond, may contain an ester bond, a carbonyl group or lactone ring. The alkyl group and alkenyl group may be linear, branched or cyclic.

Although what is shown below is mentioned as a monomer which gives a repeating unit (f1), It is not limited to these. R ^A and M ⁻ are as defined above.

Although what is shown below is mentioned as a monomer which gives a repeating unit (f2), It is not limited to these. R ^A is as defined above.

Although what is shown below is mentioned as a monomer which gives a repeating unit (f3), It is not limited to these. R ^A is as defined above.

By binding an acid generator to the polymer backbone, it is effective in reducing acid diffusion and preventing a decrease in resolution due to a slowing of acid diffusion. In addition, since the acid generator is uniformly dispersed, edge roughness is improved. When using the base polymer containing a repeating unit (f), the compounding of an individual acid generator can be skipped.

The base polymer for the positive resist material construction comprises a repeating unit (a1) or (a2) having an acid labile group as an essential component, and further repeating units (b), (c), (d), (e) and (f) is included as an optional component. The content ratio of the repeating units (a1), (a2), (b), (c), (d), (e) and (f) is 0≤a1 <1.0, 0≤a2 <1.0, 0 <a1 + a2 <1.0, 0≤b≤0.9, 0≤c≤0.9, 0≤d≤0.8, 0≤e≤0.8 and 0≤f≤0.5 are preferred, 0≤a1≤0.9, 0≤a2≤0.9, 0.1≤ a1 + a2≤0.9, 0≤b≤0.8, 0≤c≤0.8, 0≤d≤0.7, 0≤e≤0.7 and 0≤f≤0.4 are more preferable, and 0≤a1≤0.8, 0≤a2≤ More preferably, 0.8, 0.1 ≦ a1 + a2 ≦ 0.8, 0 ≦ b ≦ 0.75, 0 ≦ c ≦ 0.75, 0 ≦ d ≦ 0.6, 0 ≦ e ≦ 0.6, and 0 ≦ f ≦ 0.3. In the case where the repeating unit (f) is at least one of the repeating units (f1) to (f3), f = f1 + f2 + f3 and a1 + a2 + b + c + d + e + f = 1.0.

Base polymers for the construction of negative resist materials do not necessarily require an acid labile group. Such a base polymer contains a repeating unit (b), and contains repeating units (c), (d), (e) and / or (f) as needed. The content ratio of these repeating units is preferably 0 <b≤1.0, 0≤c≤0.9, 0≤d≤0.8, 0≤e≤0.8 and 0≤f≤0.5, and 0.2≤b≤1.0, 0≤c ≤ 0.8, 0 ≤ d ≤ 0.7, 0 ≤ e ≤ 0.7 and 0 ≤ f ≤ 0.4 are more preferred, 0.3 ≤ b ≤ 1.0, 0 ≤ c ≤ 0.75, 0 ≤ d ≤ 0.6, 0 ≤ e ≤ 0.6 and 0 ≤ f ≤ 0.3 is more preferable. In addition, when repeating unit (f) is at least 1 sort (s) among repeating units (f1)-(f3), it is f = f1 + f2 + f3 and b + c + d + e + f = 1.0.

The said base polymer can be synthesize | combined by arbitrary predetermined methods, for example, carrying out heat polymerization of the 1 or more types of monomer chosen from the monomer which gives the above-mentioned repeating unit by adding a radical polymerization initiator in the organic solvent, and carrying out heat polymerization. . Toluene, benzene, tetrahydrofuran, diethyl ether, dioxane, etc. are mentioned as an organic solvent used at the time of superposition | polymerization. Examples of the polymerization initiator used in the present invention include 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2-azobis ( 2-methylpropionate), benzoyl peroxide, lauroyl peroxide and the like. In order to start the polymerization, the system is preferably heated to 50 to 80 ° C. The reaction time is 2 to 100 hours, preferably 5 to 20 hours.

In the case of copolymerizing a monomer having a hydroxy group, the hydroxy group may be replaced with an acetal group which is easily deprotected by an acid such as an ethoxyethoxy group before polymerization, and then deprotected by a weak acid and water after the polymerization. Alternatively, the hydroxyl group may be substituted with an acetyl group, formyl group, pivaloyl group, or the like before polymerization to perform alkali hydrolysis after the polymerization.

When copolymerizing hydroxy styrene or hydroxyvinyl naphthalene, an alternative method is possible. Specifically, acetoxy styrene or acetoxy vinyl naphthalene is used in place of hydroxy styrene or hydroxy vinyl naphthalene, and after polymerization, the acetoxy group is deprotected by the alkali hydrolysis, and the polymer product is hydroxy styrene or hydroxy. You may convert into vinyl naphthalene. Ammonia water, triethylamine, etc. can be used as a base at the time of alkali hydrolysis. The reaction temperature is preferably -20 to 100 ° C, more preferably 0 to 60 ° C, and the reaction time is preferably 0.2 to 100 hours, more preferably 0.5 to 20 hours.

The base polymer has a polystyrene reduced weight average molecular weight (Mw) by GPC using tetrahydrofuran (THF) as the solvent, preferably 1,000 to 500,000, more preferably 2,000 to 30,000. If Mw is too small, the resist material will be inferior in heat resistance. When Mw of a polymer is too big | large, alkali solubility will fall and a footing phenomenon will occur easily after pattern formation.

 When the molecular weight distribution or dispersion (Mw / Mn) in the base polymer is wide, since a low molecular weight or high molecular weight polymer fraction exists, foreign matter may appear on the pattern or the shape of the pattern may deteriorate. . As the pattern rule becomes finer, the influence of molecular weight and dispersion tends to increase. Therefore, in order to obtain a resist material suitable for fine pattern dimensions, the dispersion (Mw / Mn) of the base polymer is preferably 1.0-2.0, particularly 1.0-1.5, which is narrowly dispersed.

The base polymer may contain two or more polymers having different composition ratios, Mw and Mw / Mn. In the range which does not impair the effect of this invention, although the said base polymer may contain a polymer different from the polymer mentioned above, it is preferable not to include it.

Acid generator

The resist material of the present invention may further contain an acid generator (additive acid generator) in order to function as a chemically amplified positive resist material or a chemically amplified negative resist material. As a result, the resist material is more sensitive, and the overall characteristics become more excellent, which is very useful. When the base polymer contains the repeating unit (f), that is, when the acid generator is contained in the base polymer, the addition type acid generator may not be included.

Acid generators are typically compounds (PAGs) that generate acids in response to actinic light or radiation. As PAG, as long as it is a compound which generate | occur | produces an acid by high energy ray irradiation, it is preferable to generate | occur | produce sulfonic acid, an imid acid, or methic acid. Suitable PAGs include sulfonium salts, iodonium salts, sulfonyldiazomethanes, N-sulfonyloxyimides, oxime-O-sulfonate type acid generators, and the like. Examples of PAGs include those described in paragraphs [0122] to [0142] (USP 7,537,880) of JP-A 2008-111103.

Moreover, it is preferable to have following formula (1) as PAG.

Formula (1) of, R ^101, R ¹⁰² and R ¹⁰³ is a group each optionally and independently contain a hetero atom C ₁ -C ₂₀ hydrocarbon group is 1. Any two of R ¹⁰¹ , R ¹⁰² and R ¹⁰³ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. The monovalent hydrocarbon group may be linear, branched or cyclic, and examples thereof include those mentioned above in the description of R ^a1 to R ^a3 in Formula (Aa).

As a cation of the sulfonium salt which has Formula (1), the same thing as mentioned above as a sulfonium cation which has Formula (Aa) is mentioned.

In formula (1), X <^-> is an anion which has following formula (1A), (1B), (1C) or (1D).

In formula (1A), R ^fa is a C ₁ -C ₄₀ monovalent hydrocarbon group which may contain a fluorine atom or a hetero atom. The monovalent hydrocarbon group may be linear, branched or cyclic, and examples thereof include the same as those mentioned in the description of R ¹⁰⁵ described later.

It is preferable to have a following formula (1A ') among the anions of Formula (1A).

In formula (1A '), R <^104> is a hydrogen atom or a trifluoromethyl group, Preferably it is a trifluoromethyl group. R ¹⁰⁵ is a C ₁ -C ₃₈ monovalent hydrocarbon group which may contain a hetero atom. As said hetero atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom, etc. are preferable, and an oxygen atom is the most preferable. As said monovalent hydrocarbon group represented by R <^105> , it is especially preferable that it is C6-C30 from the point which obtains high resolution in fine pattern formation. The monovalent hydrocarbon group may be linear, branched or cyclic. Examples thereof include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, heptyl group, 2-ethylhexyl group, and furnace Linear or branched alkyl groups such as a silyl group, an undecyl group, a tridecyl group, a pentadecyl group, a heptadecyl group, and an isosanyl group; Cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, 1-adamantylmethyl group, norbornyl group, norbornylmethyl group, tricyclodecanyl group, tetracyclododecanyl group, tetracyclodo Monovalent saturated cyclic aliphatic hydrocarbon groups such as decanylmethyl group and dicyclohexylmethyl group; Monovalent unsaturated aliphatic hydrocarbon groups such as allyl group and 3-cyclohexenyl group; Aralkyl groups, such as a benzyl group and a diphenylmethyl group, etc. are mentioned. As a monovalent hydrocarbon group containing a hetero atom, tetrahydrofuryl group, methoxymethyl group, ethoxymethyl group, methylthiomethyl group, acetamidomethyl group, trifluoroethyl group, (2-methoxyethoxy) methyl group, acetoxy Methyl group, 2-carboxy-1-cyclohexyl group, 2-oxopropyl group, 4-oxo-1-adamantyl group, 3-oxocyclohexyl group, etc. are mentioned. Some of the hydrogen atoms of these groups may be substituted with hetero atom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, halogen atoms, or some of the carbon atoms of these groups are hetero atoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and the like. It may be substituted by the atom containing group, As a result, it may contain hydroxy group, cyano group, carbonyl group, ether bond, ester bond, sulfonic acid ester bond, carbonate bond, lactone ring, sultone ring, carboxylic anhydride, haloalkyl group, etc. .

For the synthesis of a sulfonium salt containing an anion having the formula (1A '), see JP-A 2007-145797, JP-A 2008-106045, JP-A 2009-007327, JP-A 2009-258695 and the like. Can be. Also useful are the sulfonium salts described in JP-A 2010-215608, JP-A 2012-041320, JP-A 2012-106986, JP-A 2012-153644 and the like.

Although what is shown below is mentioned as an anion which has a formula (1A), It is not limited to these.

In formula (1B), R ^fb1 and R ^fb2 are each independently a C ₁ -C ₄₀ monovalent hydrocarbon group which may contain a fluorine atom or a hetero atom. The monovalent hydrocarbon group may be linear, branched or cyclic, and examples thereof include the same ones as exemplified in the description of R ¹⁰⁵ . R ^fb1 and R ^fb2 are preferably fluorine atoms or C ₁ -C ₄ linear fluorinated alkyl groups. R ^fb1 and R ^fb2 may be bonded to each other to form a ring together with a group to which they are bonded: -CF ₂ -SO ₂ -N ^-- SO ₂ -CF _2- . In this case, it is preferable that the group obtained by mutual coupling of R ^fb1 and R ^fb2 is a fluorinated ethylene group or a fluorinated propylene group.

In formula (1C), R ^fc1 , R ^fc2 and R ^fc3 are each independently a C ₁ -C ₄₀ monovalent hydrocarbon group which may contain a fluorine atom or a hetero atom. The monovalent hydrocarbon group may be linear, branched or cyclic, and examples thereof include the same ones as exemplified in the description of R ¹⁰⁵ . R ^fc1 , R ^fc2 and R ^fc3 are preferably fluorine atoms or C ₁ -C ₄ linear fluorinated alkyl groups. In addition, R ^fc1 and R ^fc2 may be bonded to each other to form a ring together with a group to which they are bonded: -CF ₂ -SO ₂ -C ^-- SO ₂ -CF _2- . In this case, it is preferable that the group obtained by mutual coupling | bonding of R ^fc1 and R ^fc2 is a fluorinated ethylene group or a fluorinated propylene group.

In formula (1D), R ^fd is a C ₁ -C ₄₀ monovalent hydrocarbon group which may contain a hetero atom. The monovalent hydrocarbon group may be linear, branched or cyclic, and examples thereof include the same ones as exemplified in the description of R ¹⁰⁵ .

Regarding the synthesis of a sulfonium salt containing an anion having the formula (1D), JP-A 2010-215608 and JP-A 2014-133723 can be referred to.

Although what is shown below is mentioned as an anion which has a formula (1D), It is not limited to these.

In addition, the compound containing the anion which has a formula (1D) does not have fluorine in the (alpha) position of a sulfo group, but has two trifluoromethyl groups in the (beta) position. Due to this, it has sufficient acidity to cleave the acid labile group in the resist polymer. As such, the compound is a useful PAG.

As another preferable PAG, the compound which has following formula (2) is mentioned.

In formula (2), R ²⁰¹ and R ²⁰² are C ₁ -C ₃₀ monovalent hydrocarbon groups which may each independently contain a hetero atom. R ²⁰³ is a C ₁ -C ₃₀ divalent hydrocarbon group which may contain a hetero atom. Any two of R ²⁰¹ , R ²⁰² and R ²⁰³ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. L ^A is a C ₁ -C ₂₀ divalent hydrocarbon group which may contain a single bond, an ether bond, or a hetero atom. X ^A , X ^B , X ^C and X ^D are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, provided that at least one of X ^A , X ^B , X ^C and X ^D is a fluorine atom or trifluoro It is a methyl group and k is an integer of 0-3.

The monovalent hydrocarbon group may be linear, branched or cyclic. Examples thereof include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, tert-pentyl group, n-hexyl group, n-octyl group and n- Linear or branched alkyl groups such as nonyl, n-decyl and 2-ethylhexyl groups; Cyclopentyl group, cyclohexyl group, cyclopentylmethyl group, cyclopentylethyl group, cyclopentylbutyl group, cyclohexylmethyl group, cyclohexylethyl group, cyclohexylbutyl group, norbornyl group, oxanorbornyl group, tricyclo [5.2.1.0 ^{2 , 6]} deca-group, adamantyl monovalent saturated cyclic hydrocarbon group such as a group; Although aryl groups, such as a phenyl group, a naphthyl group, anthracenyl group, etc. are mentioned, It is not limited to these. Some of the hydrogen atoms of these groups may be substituted with hetero atom-containing groups such as oxygen atoms, sulfur atoms, nitrogen atoms, and halogen atoms, and some of the carbon atoms of these groups are hetero atoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and the like. It may be substituted by the containing group, As a result, the hydroxyl group, cyano group, carbonyl group, ether bond, ester bond, sulfonic acid ester bond, carbonate bond, lactone ring, sultone ring, carboxylic anhydride, haloalkyl group, etc. may be included.

The divalent hydrocarbon group may be linear, branched or cyclic. Examples thereof include methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7- Diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group, Tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane-1,17-diyl group, etc. Linear or branched alkanediyl groups of; Divalent saturated cyclic hydrocarbon groups such as cyclopentanediyl group, cyclohexanediyl group, norbornanediyl group, and adamantanediyl group; Unsaturated cyclic divalent hydrocarbon groups, such as a phenylene group and a naphthylene group, etc. are mentioned. Some of the hydrogen atoms of these groups may be substituted with alkyl groups such as methyl group, ethyl group, propyl group, n-butyl group, tert-butyl group, and some of the hydrogen atoms of these groups are oxygen atom, sulfur atom, nitrogen atom, It may be substituted by hetero atom containing groups, such as a halogen atom, or some carbon atoms of these groups may be substituted by hetero atom containing groups, such as an oxygen atom, a sulfur atom, and a nitrogen atom, As a result, a hydroxyl group, a cyano group, and 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 anhydride, a haloalkyl group, and the like may be included. As said hetero atom, an oxygen atom is preferable.

As PAG which has Formula (2), what has following formula (2 ') is preferable.

In formula (2 '), L ^A is as defined above. R is a hydrogen atom or a trifluoromethyl group, Preferably it is a trifluoromethyl group. R ³⁰¹ , R ³⁰² and R ³⁰³ are each independently a C ₁ -C ₂₀ monovalent hydrocarbon group which may contain a hydrogen atom or a hetero atom. The monovalent hydrocarbon group may be linear, branched or cyclic, and examples thereof include the same ones as exemplified in the description of R ¹⁰⁵ . Subscripts x and y are each independently an integer of 0 to 5, and z is an integer of 0 to 4;

Although what is shown below is mentioned as PAG which has Formula (2), It is not limited to these. R is as defined above.

Among the above-mentioned PAGs, an anion having a formula (1A ') or (1D) is particularly preferred because of its low acid diffusion and excellent solubility in a resist solvent. In addition, it is particularly preferable that the acid diffusion having an anion having the formula (2 ') is very small.

Moreover, as said PAG, the sulfonium salt or iodonium salt which has an anion containing an iodine atom can also be used. As such a salt, the sulfonium salt and iodonium salt of the benzoyl iodide containing fluorinated sulfonic acid which have following formula (3-1) or (3-2) are mentioned.

In formulas (3-1) and (3-2), R ⁴⁰¹ represents a hydrogen atom, a hydroxyl group, a carboxyl group, a nitro group, a cyano group, a fluorine atom, a chlorine atom, a bromine atom, an amino group, or a fluorine atom, a chlorine atom or a bromine atom , C ₁ -C ₂₀ alkyl group, C ₁ -C ₂₀ alkoxy group, C ₂ -C ₂₀ alkoxycarbonyl group, C ₂ -C ₂₀ acyloxy group or C ₁ -C ₄ alkyl, which may contain a hydroxy group, an amino group or an alkoxy group Or a sulfonyloxy group, or -NR ⁴⁰⁷ -C (= O) -R ⁴⁰⁸ or -NR ⁴⁰⁷ -C (= O) -OR ⁴⁰⁸ , R ⁴⁰⁷ is a hydrogen atom or a halogen atom, a hydroxy group, an alkoxy group, an acyl group or Is a C ₁ -C ₆ alkyl group which may contain an acyloxy group, R ⁴⁰⁸ is a C ₁ -C ₁₆ alkyl group, a C ₂ -C ₁₆ alkenyl group, or a C ₆ -C ₁₂ aryl group, a halogen atom, a hydroxy group, an alkoxy group And may contain an acyl group or an acyloxy group.

X ¹¹ is, or r = 1 one bond or a divalent connecting group when C ₁ -C ₂₀ 2, r = 2 or 3, when a C ₁ -C ₂₀ 3 or a tetravalent linking group, the linking group is an oxygen atom, a sulfur atom, Alternatively, a nitrogen atom may be included. Rf ^{11 to} Rf ¹⁴ are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group. At least one of Rf ^{11 to} Rf ¹⁴ may be a fluorine atom or a trifluoromethyl group, or Rf ¹¹ and Rf ¹² may be combined to form a carbonyl group.

R ⁴⁰² , R ⁴⁰³ , R ⁴⁰⁴ , R ⁴⁰⁵ and R ⁴⁰⁶ are each independently a C ₁ -C ₂₀ monovalent hydrocarbon group which may contain a heteroatom. Any two of R ⁴⁰² , R ⁴⁰³ and R ⁴⁰⁴ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. The monovalent hydrocarbon group may be linear, branched or cyclic, and examples thereof include those mentioned above in the description of R ^a1 to R ^a3 in Formula (Aa).

In formula (3-1) and (3-2), r is an integer of 1-3, s is an integer of 1-5, t is an integer of 0-3.

The alkyl group, alkoxy group, alkoxycarbonyl group, acyloxy group, alkylsulfonyloxy group, alkenyl group and acyl group may be linear, branched or cyclic.

As a sulfonium salt or iodonium salt which has an anion containing an iodine atom, the sulfonium salt or iodonium salt of the iodide benzene ring containing fluorinated sulfonic acid which has following formula (3-3) or (3-4) is also mentioned.

In formulas (3-3) and (3-4), R ⁴¹¹ is a hydroxy group, a C ₁ -C ₂₀ alkyl group or an alkoxy group, a C ₂ -C ₂₀ acyl or acyloxy group, a fluorine atom, a chlorine atom, a bromine atom, An amino group or an alkoxycarbonyl substituted amino group.

R ^{412 's} are each independently a single bond or a C ₁ -C ₄ alkylene group. R ⁴¹³ is, u = 1 and it indicates a single bond or C ₁ -C ₂₀ 2-valent linking group, when the u = 2 or 3 C ₁ -C ₂₀ is a trivalent or tetravalent linking group. This linking group may contain an oxygen atom, a sulfur atom, or a nitrogen atom.

Rf ^{21 to} Rf ²⁴ are each independently a hydrogen atom, a fluorine atom or a trifluoromethyl group, and at least one of Rf ^{21 to} Rf ²⁴ is a fluorine atom or a trifluoromethyl group. Rf ²¹ and Rf ²² may be combined to form a carbonyl group.

R ⁴¹⁴ , R ⁴¹⁵ , R ⁴¹⁶ , R ⁴¹⁷ and R ⁴¹⁸ are each independently a C ₁ -C ₂₀ monovalent hydrocarbon group which may contain a hetero atom. Any two of R ⁴¹⁴ , R ⁴¹⁵ and R ⁴¹⁶ may be bonded to each other to form a ring together with the sulfur atom to which they are bonded. The monovalent hydrocarbon group may be linear, branched or cyclic, and examples thereof include those mentioned above in the description of R ^a1 to R ^a3 in Formula (Aa).

Subscript u is an integer of 1 to 3, v is an integer of 1 to 5, and w is an integer of 0 to 3;

The alkyl group, alkoxy group, acyl group, acyloxy group and alkenyl group may be linear, branched or cyclic.

As a cation of the sulfonium salt which has a formula (3-1) and (3-3), the same thing as mentioned above as a sulfonium cation which has a formula (Aa) is mentioned. As a cation of the iodonium salt which has a formula (3-2) or (3-4), the same thing as mentioned above as an iodonium cation which has a formula (Ab) is mentioned.

Although what is shown below is mentioned as an anion part of the onium salt which has Formula (3-1)-(3-4), It is not limited to these.

Moreover, as said PAG, you may use the sulfonium salt or iodonium salt which has an anion containing a bromine atom. As an anion containing a bromine atom, what substituted the iodine atom with the bromine atom in Formula (3-1)-(3-4) is mentioned. As an example of this, the thing which substituted the iodine atom by the bromine atom in the above-mentioned anion containing an iodine atom is mentioned.

When used, 0.1-50 weight part is preferable with respect to 100 weight part of base polymers, and, as for content of the said addition type acid generator, 1-40 weight part is more preferable.

Other ingredients

In addition to the onium salts, base polymers and acid generators described above, other components such as organic solvents, surfactants, dissolution inhibitors, crosslinking agents, etc. may be appropriately combined and blended according to the purpose to form a chemically amplified positive resist material or a negative resist. The material can be constructed. In the exposed portion, since the dissolution rate of the base polymer in the developing solution is accelerated by the catalytic reaction, it can be a very sensitive positive resist material or negative resist material. Moreover, the dissolution contrast and resolution of a resist film are high, there is exposure margin, it is excellent in process adaptability, the pattern shape after exposure is favorable, acid diffusion can be suppressed and a compact dimension difference is small. In this advantage, the material has high practicality and can be very effective as a pattern forming material for producing a VLSI.

As the organic solvent, those described in paragraphs [0144] to [0145] (USP 7,537,880) of JP-A 2008-111103 are used. As said solvent, Ketones, such as cyclohexanone, cyclopentanone, and a 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; Ethers such as propylene glycol monomethyl ether (PGME), ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether and diethylene glycol dimethyl ether; Propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monoethyl ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, t-butyl acetate, t-butyl propionate, Esters such as propylene glycol monot-butyl ether acetate; Lactones, such as (gamma) -butyrolactone, are mentioned, These solvents may be used individually or in mixture.

100-10,000 weight part is preferable with respect to 100 weight part of base polymers, and, as for content of the said organic solvent, 200-8,000 weight part is more preferable.

Examples of the surfactants include those described in paragraphs [0165] to [0166] of JP-A 2008-111103. By adding surfactant, the applicability of a resist material can be improved or controlled. Surfactants may be used alone or in combination, and the content of the surfactant is preferably 0.0001 to 10 parts by weight based on 100 parts by weight of the base polymer.

In the case of a positive resist material, by dissolving a dissolution inhibiting agent, the difference in the dissolution rate of the exposed portion and the unexposed portion can be further increased, and the resolution can be further improved. In the case of a negative resist material, the dissolution rate of the resist film in an exposure part can be reduced by adding a crosslinking agent, and a negative pattern can be formed.

As said dissolution inhibiting agent, the compound which substituted the hydrogen atom of the phenolic hydroxy group of the compound which has two or more phenolic hydroxy groups in a molecule by the acid labile group at the ratio of 0-100 mol% on average as a whole, or 1 or more in a molecule | numerator The compound which substituted the hydrogen atom of the said carboxyl group of the compound which has a carboxyl group by the acid labile group in the ratio of an average of 50-100 mol% can be used, and both compounds have a molecular weight of 100-1,000, Preferably it is 150-800. Typically, bisphenol A, trisphenol, phenolphthalein, cresol novolac, naphthalene carboxylic acid, adamantane carboxylic acid, derivatives in which hydroxyl groups of carboxylic acids or hydrogen atoms of carboxyl groups are substituted with acid labile groups, etc. may be mentioned. USP 7,771,914 (paragraphs [0155] to [0178] of JP-A 2008-122932).

In the case of a positive resist material, 0-50 weight part is preferable with respect to 100 weight part of base polymers, and, as for content of the said dissolution inhibitor, 5-40 weight part is more preferable. Dissolution inhibitors may be used alone or in combination.

As the crosslinking agent, an epoxy compound, melamine compound, guanamine compound, glycoluril compound and urea compound, isocyanate compound, azide compound, alkenyl ether substituted with at least one group selected from methylol group, alkoxymethyl group and acyloxymethyl group The compound etc. which have a double bond, such as group, can be used suitably. These materials may be used as an additive or may be introduced as a pendant group in the polymer side chain. The compound containing a hydroxyl group can also be used as a crosslinking agent. The crosslinking agents may be used alone or in combination.

As an epoxy compound in the said crosslinking agent, tris (2, 3- epoxypropyl) isocyanurate, trimethylol methane triglycidyl ether, trimethylol propane triglycidyl ether, triethylol ethane triglycidyl ether, etc. are suitable. Examples of the melamine compound include compounds in which 1 to 6 methylol groups of hexamethylolmelamine, hexamethoxymethylmelamine and hexamethylolmelamine are methoxymethylated, and mixtures thereof, hexamethoxyethylmelamine, hexaacyloxymethylmelamine and hexa The compound in which 1-6 of the methylol groups of methylolmelamine acyloxymethylated, its mixture, etc. are mentioned. Examples of the guanamine compound include compounds in which 1 to 4 methylol groups of tetramethylolguanamine, tetramethoxymethylguanamine and tetramethylolguanamine are methoxymethylated, and mixtures thereof, tetramethoxyethylguanamine and tetraacyloxy The compound in which 1-4 methylol groups of guanamine and tetramethylol guanamine acyloxymethylated, its mixture, etc. are mentioned. As a glycoluril compound, the compound in which 1-4 of the methylol groups of tetramethylol glycoluril, tetramethoxyglycoluril, tetramethoxymethylglycoluril, and tetramethylolglycoluril methoxymethylated, its mixture, and tetramethylol glycol The compound which 1-4 of the methylol groups of usyl acyloxymethylated, its mixture, etc. are mentioned. As a urea compound, the compound in which 1-4 methylol groups of tetramethylol urea, tetramethoxymethylurea, and tetramethylolurea methoxymethylated, its mixture, tetramethoxyethylurea, etc. are mentioned.

As an isocyanate compound, tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, etc. are suitable. As the azide compound, 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, 4,4'-oxybisazide and the like are suitable. As a compound containing an alkenyl ether group, ethylene glycol divinyl ether, triethylene glycol divinyl ether, 1,2-propanediol divinyl ether, 1,4-butanediol divinyl ether, tetramethylene glycol divinyl ether, neopentyl Glycol divinyl ether, trimethylol propane trivinyl ether, hexanediol divinyl ether, 1, 4- cyclohexanediol divinyl ether, pentaerythritol trivinyl ether, pentaerythritol tetravinyl ether, sorbitol tetravinyl ether, sorbitol pentavinyl ether And trimethylolpropane trivinyl ether.

In the case of a negative resist material, 0.1-50 weight part is preferable with respect to 100 weight part of base polymers, and, as for content of a crosslinking agent, 1-40 weight part is more preferable.

You may mix | blend the quencher other than the sulfonium salt of the iodide benzene ring containing sulfonamide with the resist material of this invention. Other quenchers are typically selected from conventional compounds of the conventional type. As a basic compound of a conventional form, primary, secondary, tertiary aliphatic amines, hybrid amines, aromatic amines, heterocyclic amines, a nitrogen-containing compound having a carboxyl group, a nitrogen-containing compound having a sulfonyl group, and a hydroxy group Nitrogen-containing compounds, nitrogen-containing compounds having hydroxyphenyl groups, alcoholic nitrogen-containing compounds, amides, imides, carbamate and the like. Primary, secondary and tertiary amine compounds described in paragraphs [0146] to [0164] of JP-A 2008-111103, in particular, hydroxyl groups, ether bonds, ester bonds, lactone rings, cyano groups and sulfonic acid esters The amine compound which has a group, the compound which has a carbamate group as described in JP 3790649, etc. are also included. By adding such a basic compound, the diffusion rate of the acid in the resist film can be further suppressed or the pattern shape can be corrected.

As another quencher, onium salts such as sulfonium salts, iodonium salts, and ammonium salts of sulfonic acids and carboxylic acids in which the α position described in USP 8,795,942 (JP-A 2008-158339) are not fluorinated can be used. (alpha) fluorinated sulfonic acid, imide acid, and methic acid are necessary in order to deprotect the acid labile group of a carboxylic acid ester, but (alpha) non-fluorinated sulfonic acid and carboxylic acid are released by salt exchange with (alpha) non-fluoride onium salt. α non-fluorinated sulfonic acids and carboxylic acids function as quenchers because they do not cause deprotection reactions.

Other quenchers are also useful as polymer quenchers described in USP 7,598,016 (JP-A 2008-239918). This polymer type quencher is oriented on the surface of the resist after coating to increase the spherical shape of the resist after the pattern. The polymer type quencher also has an effect of preventing the reduction of the thickness of the resist pattern and the rounding of the pattern top when the protective film for immersion exposure is applied.

0-5 weight part is preferable with respect to 100 weight part of base polymers, and, as for content of another quencher, 0-4 weight part is more preferable.

You may mix | blend with the resist material of this invention the polymer additive (or water repellency improving agent) for improving the water repellency of the resist film surface after spin coating. The water repellency enhancer can be used for immersion lithography that does not use a top coat. As the water repellency improving agent, a high molecular compound having a fluoroalkyl group, a high molecular compound having a 1,1,1,3,3,3-hexafluoro-2-propanol moiety having a specific structure, and the like are suitable, and JP-A 2007- 297590, JP-A 2008-111103 and the like. The water repellency enhancer added to the resist material needs to be dissolved in an organic solvent developer. The water repellency enhancer having the 1,1,1,3,3,3-hexafluoro-2-propanol residue of the specific structure described above has good solubility in a developer. A high molecular compound having an amino group or an amine salt copolymerized as a repeating unit can act as a water repellent additive, and has a high effect of preventing the evaporation of an acid in PEB to prevent a poor opening of a hole pattern after development. The water repellency improving agent may be used alone or in combination. The appropriate amount of the water repellency improving agent is 0 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight based on 100 parts by weight of the base polymer.

Acetylene alcohol can also be mix | blended with the resist material of this invention. As the acetylene alcohols, those described in paragraphs [0179] to [0182] of JP-A 2008-122932 are suitable. The suitable compounding quantity of acetylene alcohols is 0-5 weight part with respect to 100 weight part of base polymers.

Pattern Formation Method

The resist material of the present invention is used in the manufacture of various integrated circuits. Pattern formation using the resist material can be performed by known lithography techniques. Such techniques generally include coating, baking, exposure and development. If necessary, additional steps can be added.

For example, the resist material may be a substrate for integrated circuit fabrication (eg, Si, SiO ₂ , SiN, SiON, TiN, WSi, BPSG, SOG, organic antireflection film, etc.) or a substrate for mask circuit fabrication (eg, Cr, CrO, CrON, MoSi). ₂ , SiO _2, etc.) is first applied by a suitable coating technique such as spin coat, roll coat, flow coat, dip coat, spray coat, doctor coat or the like. The coating is baked on a hot plate at 60 to 150 ° C. for 10 seconds to 30 minutes, preferably at 80 to 120 ° C. for 30 seconds to 20 minutes. The resulting resist film is generally 0.01 to 2.0 mu m in thickness.

Subsequently, high energy rays such as ultraviolet rays, far ultraviolet rays, EB, EUV, X-rays, soft X-rays, excimer laser light, gamma rays, synchrotron radiation, and the like, are subjected to direct exposure through a predetermined mask. The exposure amount is preferably exposed to about 1 to 200 mJ / cm 2, more preferably about 10 to 100 mJ / cm 2, or about 0.1 to 100 μC / cm 2, and more preferably about 0.5 to 50 μC / cm 2. . Subsequently, the resist film is further baked (PEB) on a hot plate at 60 to 150 ° C for 10 seconds to 30 minutes, preferably at 80 to 120 ° C for 30 seconds to 20 minutes.

PEB may or may not be performed. In particular, in the case of the anion bound PAG polymer containing the said repeating unit (f2) or (f3), sulfonic acid generate | occur | produces by exposure and alkali solubility improves. Thus, even without PEB, the exposed portion of the resist film is dissolved in alkali. If PEB is not carried out, the image blur due to acid diffusion is eliminated, and finer pattern formation can be expected than with PEB.

When PEB is not performed, since the deprotection reaction by an acid does not occur, the resist material of this invention functions as a nonchemically amplified resist material. In this case, since the melt contrast is low, the film | membrane reduction of a pattern and the residual film of a space part arise after development. In non-chemically amplified resist materials, how to improve dissolution contrast is a key point.

In the case of the anion bound PAG polymer containing the said repeating unit (f2) or (f3), (alpha)-fluorosulfonic acid generate | occur | produces by exposure and the solubility to alkaline developing solution improves. By adding an onium salt of sulfoic acid in which the α position is not fluorinated, generation of α-fluorosulfonic acid is suppressed by salt exchange with it. If the exposure amount is further increased, alkali solubility is improved by decomposing the onium salt of sulfonic acid or carboxylic acid in which the α position is not fluorinated. In other words, contrast is improved by dissolution inhibiting property in an area having a small exposure amount and improvement in dissolution acceleration in a region having a large exposure amount. Since the rate of ion exchange reaction is fast and advances at room temperature, it is not necessary to perform PEB. Since the onium salt having the formula (A) is also a salt of a weaker acid than α-fluorosulfonic acid, ion exchange of the same formula occurs. This improves contrast even when PEB is not performed.

The resist film is then developed into a developer in the form of a base aqueous solution by conventional methods such as dipping, puddle, and spray, for 3 seconds to 3 minutes, preferably 5 seconds to 2 minutes. Typical developer is 0.1 to 10% by weight, preferably 2 to 5% by weight of tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), tetrapropylammonium hydroxide (TPAH), tetrabutyl It is aqueous solution, such as ammonium hydroxide (TBAH). When the resist film is dissolved in the developer, the portion irradiated with light is dissolved in the developer, and the portion not exposed is not dissolved. In this way, the desired positive pattern is formed on the substrate. In the case of a negative resist, in contrast to the case of a positive resist, that is, a portion of the resist film to which light is irradiated is insolubilized in a developer, and an unexposed portion is dissolved. It is to be understood that the resist material of the present invention is optimal 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.

In alternative embodiments, a negative pattern may be formed by organic solvent development, using a positive resist material comprising a base polymer having an acid labile group. The developer used at this time is preferably 2-octanone, 2-nonanone, 2-heptanone, 3-heptanone, 4-heptanone, 2-hexanone, 3-hexanone, diisobutyl ketone, methylcyclone Hexanone, acetophenone, methylacetophenone, propyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, butenyl acetate, isopentyl acetate, propyl formate, butyl formate, isobutyl formate, pentyl formate, isopentyl formate, valeric acid Methyl, methyl pentene, methyl crotonate, ethyl crotonate, methyl propionate, ethyl propionate, ethyl 3-ethoxypropionate, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, isobutyl lactate, pentyl lactate, isopentyl lactate, Methyl 2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, methyl benzoate, ethyl benzoate, phenyl acetate, benzyl acetate, methyl phenyl acetate, benzyl formate, phenyl ethyl formate, 3-phenylprop Acid methyl, propionic acid is selected from benzyl, phenyl ethyl acetate, 2-phenylethyl, and mixtures thereof.

At the end of development, the resist film is rinsed. As the rinse liquid, a solvent that is miscible with the developer and does not dissolve the resist film is preferable. As such a solvent, alcohols of 3 to 10 carbon atoms, ether compounds of 8 to 12 carbon atoms, alkanes of 6 to 12 carbon atoms, alkenes, alkynes, and aromatic solvents are suitable. Specifically, as the alcohol having 3 to 10 carbon atoms, n-propyl alcohol, isopropyl alcohol, 1-butyl alcohol, 2-butyl alcohol, isobutyl alcohol, t-butyl alcohol, 1-pentanol, 2-pentanol, 3 -Pentanol, t-pentyl alcohol, neopentyl alcohol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-3-pentanol, cyclopentanol, 1-hexanol, 2-hexane Ol, 3-hexanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 3,3-dimethyl-2-butanol, 2-ethyl-1-butanol, 2-methyl-1 -Pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4 -Methyl-1-pentanol, 4-methyl-2-pentanol, 4-methyl-3-pentanol, cyclohexanol, 1-octanol and the like are suitable. Examples of the ether compound having 8 to 12 carbon atoms include di-n-butyl ether, diisobutyl ether, di-s-butyl ether, di-n-pentyl ether, diisopentyl ether, di-s-pentyl ether, and di-t. -Pentyl ether, di-n-hexyl ether and the like are suitable. Examples of alkanes having 6 to 12 carbon atoms include hexane, heptane, octane, nonane, decane, undecane, dodecane, methylcyclopentane, dimethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, cycloheptane, cyclooctane and cyclononane Etc. are appropriate. As the alkene having 6 to 12 carbon atoms, hexene, heptene, octene, cyclohexene, methylcyclohexene, dimethylcyclohexene, cycloheptene and cyclooctene are suitable. As alkynes having 6 to 12 carbon atoms, hexine, heptin, octin and the like are suitable. As an aromatic solvent, toluene, xylene, ethylbenzene, isopropylbenzene, t-butylbenzene, mesitylene, etc. are suitable. You may use these solvents individually or in mixture.

By rinsing, the risk of collapse of the resist pattern and generation of defects can be reduced. However, rinsing is not necessary. By not rinsing, the amount of solvent used can be reduced.

Post-development hole patterns or trench patterns may be shrunk with Thermalflow, RELACS® or DSA technology. By applying a shrinkage agent on the hole pattern, crosslinking of the shrinkage agent may occur at the surface of the resist by diffusion of an acid catalyst from the resist layer during baking, so that the shrinkage agent may be attached to the sidewall of the hole pattern. The firing temperature is preferably 70 to 180 ° C, more preferably 80 to 170 ° C, and the time is preferably 10 to 300 seconds. Reduce the hole pattern by removing excess shrinkage.

Example

Hereinafter, although an Example of this invention is shown and this invention is demonstrated concretely, this invention is not limited to the following Example. The abbreviation "pbw" is parts by weight.

Synthesis Example  1-1

Synthesis of triphenylsulfonium N-[(trifluoromethyl) sulfonyl] -2,3,5-triiodobenzamide (sulfonium salt 1)

After heating a mixed liquid of 100 g of 2,3,5-triiodobenzoic acid, 0.73 g of dimethylformamide, and 700 g of chloroform to 60 ° C, 47.6 g of thionyl chloride was added dropwise thereto. The solution was stirred at 60 ° C. for 21 hours, and then concentrated under reduced pressure to remove chloroform and unreacted thionyl chloride. 500 g of hexane was added to the concentrate, and the mixture was stirred for 1 hour to precipitate a solid. The obtained solid was filtered and washed once with hexane to give 97 g of 2,3,5-triiodobenzoyl chloride as a solid.

To a mixture of 2.24 g of trifluoromethanesulfonylamide, 3.73 g of potassium carbonate, and 40 g of acetonitrile, a portion (10.1 g) of 2,3,5-triiodobenzoyl chloride was added thereto, followed by stirring at room temperature for 15 hours. . Then, 120 g of deionized water was added dropwise to the reaction solution to quench the reaction, and then 6.74 g of triphenylsulfonium methyl sulfate and 80 g of methylene chloride were added and stirred. After the insoluble content was removed by filtration, the organic layer was separated. The obtained organic layer was washed in order of 40 g of deionized water, 40 g of 2.5 mass% hydrochloric acid, 40 g of deionized water, 60 g of aqueous sodium bicarbonate solution and 40 g of deionized water. The washed organic layer was concentrated under reduced pressure. 60 g of tert-butyl methyl ether was added to the obtained concentrate, followed by stirring. After the supernatant was removed, the residue was concentrated under reduced pressure to give the desired compound triphenylsulfonium N-[(trifluoromethyl) sulfonyl] -2,3,5-triiodobenzamide (referred to as sulfonium salt 1) 10.5 g was obtained as an oil (yield 78%).

Sulfonium salt 1 was analyzed by spectroscopy. IR spectral data is shown below. NMR spectra, ¹ H-NMR and ¹⁹ F-NMR in DMSO-d ₆ are shown in FIGS. 1 and 2, respectively. Trace amounts of the residual solvent (tert-butyl methyl ether and water) have been observed in ¹ H-NMR analysis.

IR (D-ATR): ν = 3520, 3061, 2972, 1628, 1518, 1476, 1447, 1387, 1363, 1304, 1238, 1196, 1117, 1078, 1021, 998, 925, 865, 821, 748, 711 , 684, 614, 581, 502 cm ^-1

Synthesis Example  1-2 to 1-24

Synthesis of Sulfonium Salts 2-15, Iodonium Salts 1-3, and Ammonium Salts 1-6

The structure of the sulfonium salt 1-15, the iodonium salt 1-3, and the ammonium salt 1-6 of the iodide benzene ring containing sulfonamide used for the resist material of this invention are shown below.

The sulfonium salts 2 to 15 and the iodonium salts 1 to 3 are used for ion exchange of iodide benzene ring-containing sulfonamides to impart the following anions and sulfonium methane sulfonates to impart the following cations, respectively, similarly to Synthesis Example 1-1. Synthesis by Ammonium salt 1 and 2 were synthesize | combined by the neutralization reaction of the iodide benzene ring containing sulfonamide which gives the following anion, and a quaternary ammonium hydroxide, and the ammonium salts 3-6 contain the iodide benzene ring containing sulfonamide which give the following anion; It synthesize | combined by the neutralization reaction of a tertiary amine compound.

Synthesis Example  2-1 to 2-5

Synthesis of Base Polymers (Polymers 1-5)

The appropriate monomer was combined to carry out copolymerization reaction under a tetrahydrofuran (THF) solvent, poured a reaction solution into methanol for crystallization, repeated washing with hexane, and then isolated and dried to prepare a base polymer. The composition of the obtained base polymer, referred to as base polymers 1 to 6, was analyzed by ¹ H-NMR spectroscopy, and Mw and Mw / Mn were analyzed by polystyrene conversion by GPC using THF as a solvent.

Example  1 to 30 and Comparative example  1 to 7

The polymer and the selected component were dissolved in a solvent by the composition shown in Tables 1-3, and it filtered with the filter of 0.2 micrometer pore size, and the resist material was prepared. The solvent contained 100 ppm of surfactant FC-4430 (3M). The components in Tables 1-3 are as follows.

Organic solvents:

PGMEA (propylene glycol monomethyl ether acetate)

GBL (γ-butyrolactone)

CyH (cyclohexanone)

PGME (propylene glycol monomethyl ether)

DAA (Diacetone Alcohol)

Acid generators: PAG 1 to PAG 7 of formula

Comparative Kenchers 1 to 6 of the following structural formulas

EB Lithography  exam

An antireflection film (DUV-62, Nissan Chemical Corp.) having a thickness of 60 nm was coated on the silicon substrate. Each resist material shown in Tables 1-3 was spin-coated on the said board | substrate, and prebaked at 105 degreeC for 60 second on the hotplate, and the resist film of thickness 50nm was produced. The resist film was exposed to an electron beam using an EB drawing apparatus ELS-F125 (Elionix Co. Ltd., acceleration voltage 125 kV), and then fired (PEB) for 60 seconds at a temperature shown in Tables 1 to 3 on a hot plate. It developed for 30 second with 2.38 weight% TMAH aqueous solution, and formed the pattern. In Examples 1-13, 15-30, and Comparative Examples 1-6, the positive resist pattern, ie, the hole pattern of dimension 24nm, was formed. In Example 14 and Comparative Example 7, a negative resist pattern, that is, a dot pattern having a dimension of 24 nm was formed.

The resist pattern was observed under CD-SEM (CG-5000, Hitachi High-Technologies Corp.). The exposure amount when the hole or dot pattern was formed in the dimension of 24 nm was reported as the sensitivity. The diameter of the hole or dot at this time was measured by 50 points, the dimensional variation (3σ) was calculated and reported as a CDU.

The resist composition is shown in Tables 1 to 3 together with the sensitivity and CDU of EB lithography.

In Tables 1-3, it turned out that the resist material of this invention containing the onium salt of Formula (A) is highly sensitive, and CDU was improved.

Japanese Patent Application Nos. 2018-104855 and 2019-028583 are incorporated herein by reference.

While some preferred embodiments have been described, many variations and modifications may be made in light of the above teachings. Accordingly, it is to be understood that the invention may be practiced otherwise than as specifically described without departing from the scope of the appended claims.

Claims (15)

A resist material comprising a base polymer and an onium salt having the following formula (A):

Wherein R ¹ represents hydrogen, hydroxy, a C ₁ -C ₆ alkyl group, a C ₁ -C ₆ alkoxy group, a C ₂ -C ₇ acyloxy group, a C ₂ -C ₇ alkoxycarbonyl group, a C ₁ -C ₄ alkylsulfo Nyloxy group, fluorine, chlorine, bromine, amino, nitro, cyano, -NR ^1A -C (= O) -R ^1B or -NR ^1A -C (= O) -OR ^1B , the alkyl group, alkoxy group, acyl Some or all of the hydrogen atoms of the oxy group, the alkoxycarbonyl group and the alkylsulfonyloxy group may be substituted with halogen atoms, R ^1A is hydrogen or a C ₁ -C ₆ alkyl group, and R ^1B is a C ₁ -C ₆ alkyl group or C ₂ -C ₈ alkenyl group,
R ² is a C ₁ -C ₁₀ alkyl group or a C ₆ -C ₁₀ aryl group, and part or all of its hydrogen atoms are amino, nitro, cyano, C ₁ -C ₁₂ alkyl, C ₁ -C ₁₂ alkoxy, C ₂ May be substituted with -C ₁₂ alkoxycarbonyl, C ₂ -C ₁₂ acyl, C ₂ -C ₁₂ alkylcarbonyloxy, hydroxy or halogen,
X ¹ is a single bond or a C ₁ -C ₂₀ divalent linking group, and may include an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen, a hydroxy group, or a carboxyl group,
m and n are integers satisfying 1 ≦ m ≦ 5, 0 ≦ n ≦ 4 and 1 ≦ m + n ≦ 5,
M ⁺ is a sulfonium cation having formula (Aa), an iodonium cation having formula (Ab) or an ammonium cation having formula (Ac):

Wherein, R ^a1 ~R ^a3 independently is halogen, or contains a heteroatom and may good C ₁ -C _{20 1,} or a hydrocarbon group, or R ^a1, in which the dog 2 of R ^a2 and R ^a3 each other to which they are attached, respectively You may form a ring with the sulfur atom to combine,
R ^a4 and R ^a5 are each independently a halogen or C ₁ -C ₂₀ monovalent hydrocarbon group which may contain a hetero atom,
R ^a6 to R ^a9 are each independently hydrogen or a C ₁ -C ₂₄ monovalent hydrocarbon group, and are halogen, hydroxy, carboxy, ether bond, ester bond, thiol, thioester bond, thionoester bond, dithioester bond , An amino group, a nitro group, a sulfone group or a ferrocenyl group may be included, R ^a6 and R ^a7 may be bonded to each other to form a ring together with the nitrogen atom to which they are bonded, a pair of R ^a6 and R ^a7 and R ^a8 A pair of and R ^a9 may be bonded to each other to form a spiro ring together with the nitrogen atom to which they are bonded, R ^a8 and R ^a9 may be combined to form = C (R ^a10 ) (R ^a11 ), and R ^a10 and R ^a11 is each independently hydrogen or a C ₁ -C ₁₆ monovalent hydrocarbon group, and R ^a10 and R ^a11 may be bonded to each other to form a ring together with the carbon and nitrogen atoms to which they are bonded, and a double bond and oxygen in the ring , Sulfur or vagina It may contain an atom. The resist material of Claim 1 whose m is an integer which satisfy | fills 2 <= m <= 4. The resist material of claim 1, further comprising an acid generator capable of generating sulfonic acid, imide acid, or meted acid. The resist material according to claim 1, further comprising an organic solvent. The resist material according to claim 1, wherein the base polymer comprises a repeating unit having the following formula (a1) or a repeating unit having the following formula (a2):

In the formula, each R ^A is independently hydrogen or methyl, Y ¹ is a C ₁ -C ₁₂ linking group including a single bond, a phenylene group or a naphthylene group, or an ester bond or a lactone ring, and Y ² is a single bond or It is an ester bond and R <^11> and R <^12> is an acid labile group, respectively. The resist material of claim 5 which is a chemically amplified positive resist material. The resist material of claim 1 wherein said base polymer does not comprise an acid labile group. 8. The resist material of claim 7, further comprising a crosslinking agent. 8. The resist material of claim 7, wherein the resist material is a chemically amplified negative resist material. The resist material according to claim 1, wherein the base polymer further comprises at least one repeating unit selected from repeating units having the following formulas (f1) to (f3):

In the formula, each R ^A is independently hydrogen or methyl,
Z ¹ is a single bond, a phenylene group, -OZ ^11- , -C (= O) -OZ ¹¹ -or -C (= O) -NH-Z ^11- , and Z ¹¹ is a C ₁ -C ₆ alkanediyl group , A C ₂ -C ₆ alkenediyl group or a phenylene group, and may include a carbonyl, ester bond, ether bond or hydroxy group,
Z ² is a single bond, -Z ²¹ -C (= O) -O-, -Z ²¹ -O- or -Z ²¹ -OC (= O)-, Z ²¹ is a C ₁ -C ₁₂ alkanediyl group , May contain a carbonyl group, an ester bond or an ether bond,
Z ³ is a single bond, methylene, ethylene, phenylene, fluorinated phenylene, -C (= O) -OZ ³¹ -or -C (= O) -NH-Z ^31- , and Z ³¹ is C ₁ -C ₆ An alkanediyl group, a phenylene group, a fluorinated phenylene group, a phenylene group substituted with trifluoromethyl, or a C ₂ -C ₆ alkenediyl group, and may include a carbonyl group, an ester bond, an ether bond or a hydroxyl group,
A is hydrogen or trifluoromethyl,
R ²¹ to R ²⁸ are each independently a C ₁ -C ₂₀ monovalent hydrocarbon group which may contain a hetero atom, any two of R ²³ , R ²⁴ and R ²⁵ or any of R ²⁶ , R ²⁷ and R ²⁸ Two may be bonded to each other to form a ring together with a sulfur atom to which they are bonded;
M ⁻ is a nonnucleophilic counter ion. The resist material of claim 1, further comprising a surfactant. A method of forming a pattern comprising: applying the resist material of claim 1 to a substrate; forming a resist film by heating; exposing the resist film to high energy rays; and developing the exposed resist film to a developer; . The pattern forming method according to claim 12, wherein the high energy ray is an ArF excimer laser having a wavelength of 193 nm or a KrF excimer laser having a wavelength of 248 nm. The pattern formation method of Claim 12 whose said high energy ray is EB or EUV of wavelength 3-15 nm. Sulfonium salts having the formula (B):

Wherein R ¹ represents hydrogen, hydroxy, a C ₁ -C ₆ alkyl group, a C ₁ -C ₆ alkoxy group, a C ₂ -C ₇ acyloxy group, a C ₂ -C ₇ alkoxycarbonyl group, a C ₁ -C ₄ alkylsulfo Nyloxy group, fluorine, chlorine, bromine, amino, nitro, cyano, -NR ^1A -C (= O) -R ^1B or -NR ^1A -C (= O) -OR ^1B , the alkyl group, alkoxy group, acyl Some or all of the hydrogen atoms of the oxy group, alkoxycarbonyl group and alkylsulfonyloxy group may be substituted with halogen, R ^1A is hydrogen or C ₁ -C ₆ alkyl group, R ^1B is C ₁ -C ₆ alkyl group or C ₂ -C ₈ alkenyl group,
R ² is a C ₁ -C ₁₀ alkyl group or a C ₆ -C ₁₀ aryl group, and part or all of its hydrogen atoms are amino, nitro, cyano, C ₁ -C ₁₂ alkyl, C ₁ -C ₁₂ alkoxy, C ₂ May be substituted with -C ₁₂ alkoxycarbonyl, C ₂ -C ₁₂ acyl, C ₂ -C ₁₂ alkylcarbonyloxy, hydroxy or halogen,
X ¹ is a single bond or a C ₁ -C ₂₀ divalent linking group, and may include an ether bond, a carbonyl group, an ester bond, an amide bond, a sultone ring, a lactam ring, a carbonate bond, a halogen, a hydroxy group, or a carboxyl group,
m and n are integers satisfying 1 ≦ m ≦ 5, 0 ≦ n ≦ 4 and 1 ≦ m + n ≦ 5,
R ^a1 to R ^a3 are each independently a halogen or C ₁ -C ₂₀ monovalent hydrocarbon group which may contain a hetero atom, or any two of R ^a1 , R ^a2 and R ^a3 are mutually bonded to each other and are bonded to each other; You may form a ring with an atom.

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